General Description
The MAX1032/MAX1033 multirange, low-power, 14-bit,
successive-approximation, analog-to-digital converters
(ADCs) operate from a single +5V supply and achieve
throughput rates up to 115ksps. A separate digital sup-
ply allows digital interfacing with 2.7V to 5.25V systems
using the SPI™-/QSPI™-/MICROWIRE™-compatible
serial interface. Partial power-down mode reduces the
supply current to 1.3mA (typ). Full power-down mode
reduces the power-supply current to 1µA (typ).
The MAX1032 provides eight (single-ended) or four
(true differential) analog input channels. The MAX1033
provides four (single-ended) or two (true differential)
analog input channels. Each analog input channel is
independently software programmable for seven sin-
gle-ended input ranges (0 to +6V, -6V to 0, 0 to +12V,
-12V to 0, ±3V, ±6V, and ±12V), and three differential
input ranges (±6V, ±12V, ±24V).
An on-chip +4.096V reference offers a small convenient
ADC solution. The MAX1032/MAX1033 also accept an
external reference voltage between 3.800V and 4.136V.
The MAX1032 is available in a 24-pin TSSOP package
and the MAX1033 is available in a 20-pin TSSOP pack-
age. Each device is specified for operation from -40°C
to +85°C.
Applications
Industrial Control Systems
Data-Acquisition Systems
Avionics
Robotics
Features
♦Software-Programmable Input Range for Each
Channel
♦Single-Ended Input Ranges
0 to +6V, -6V to 0, 0 to +12V, -12V to 0, ±3V,
±6V, and ±12V
♦Differential Input Ranges
±6V, ±12V, and ±24V
♦Eight Single-Ended or Four Differential Analog
Inputs (MAX1032)
♦Four Single-Ended or Two Differential Analog
Inputs (MAX1033)
♦±16.5V Overvoltage Tolerant Inputs
♦Internal or External Reference
♦115ksps Maximum Sample Rate
♦Single +5V Power Supply
♦20-/24-Pin TSSOP Package
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
________________________________________________________________ Maxim Integrated Products 1
Pin Configurations
Ordering Information
24
23
22
21
20
19
18
17
1
2
3
4
5
6
7
8
AGND1
AGND2
AVDD2
AGND3CH2
CH1
CH0
AVDD1
TOP VIEW
REF
REFCAP
DVDD
DVDDO
CH6
CH5
CH4
CH3
16
15
14
13
9
10
11
12
DGND
DGNDO
DOUT
SCLKSSTRB
DIN
CS
CH7
TSSOP
MAX1032
+
19-3573; Rev 3; 7/07
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
PART
PIN-PACKAGE
CHANNELS
PKG CODE
MAX1032BEUG+*
24 TSSOP 8 U24-1
MAX1033BEUP+
20 TSSOP 4 U20-2
SPI and QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corp. Pin Configurations continued at end of data sheet.
*Future product—contact factory for availability.
+Denotes a lead-free package.
Note: All devices are specified over the -40°C to +85°C oper-
ating temperature range.
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(AVDD1 = AVDD2 = DVDD = DVDDO = 5V, AGND1 = DGND = DGNDO = AGND2 = AGND3 = 0, fCLK = 3.5MHz (50% duty cycle),
external clock mode, VREF = 4.096V (external reference operation), REFCAP = AVDD1, maximum single-ended bipolar input range
(±12V), CDOUT = 50pF, CSSTRB = 50pF, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
AVDD1 to AGND1 ....................................................-0.3V to +6V
AVDD2 to AGND2 ....................................................-0.3V to +6V
DVDD to DGND ........................................................-0.3V to +6V
DVDDO to DGNDO ..................................................-0.3V to +6V
DVDD to DVDDO......................................................-0.3V to +6V
DVDD, DVDDO to AVDD1 ........................................-0.3V to +6V
AVDD1, DVDD, DVDDO to AVDD2 ..........................-0.3V to +6V
DGND, DGNDO, AGND3, AGND2 to AGND1 ......-0.3V to +0.3V
CS, SCLK, DIN, DOUT, SSTRB to
DGNDO ............................................-0.3V to (DVDDO + 0.3V)
CH0–CH7 to AGND1 .........................................-16.5V to +16.5V
REF, REFCAP to AGND1.......................-0.3V to (AVDD1 + 0.3V)
Continuous Current (any pin) ...........................................±50mA
Continuous Power Dissipation (TA= +70°C)
20-Pin TSSOP (derate 11mW/°C above +70°C) ..........879mW
24-Pin TSSOP (derate 12.2mW/°C above +70°C) .......976mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature .....................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
DC ACCURACY (Notes 1, 2)
Resolution 14 Bits
Integral Nonlinearity INL
±0.25
±1 LSB
Differential Nonlinearity DNL No missing codes ±1 LSB
Transition Noise External or internal reference 1
LSBRMS
Unipolar 0
±20
Single-ended inputs
Bipolar
-1.0 ±10
Unipolar 0
±40
Offset Error
Differential inputs
(Note 3) Bipolar
-2.0 ±20
mV
Channel-to-Channel Gain
Matching Unipolar or bipolar
0.025
%FSR
Channel-to-Channel Offset Error
Matching Unipolar or bipolar 1 mV
Unipolar 10
Offset Temperature Coefficient Bipolar 5
ppm/°C
Unipolar
±0.5
Gain Error Bipolar
±0.3
%FSR
Unipolar 1.5
Gain Temperature Coefficient Bipolar 1.0
ppm/°C
Unipolar Endpoint Overlap Negative unipolar full scale to positive
unipolar zero-scale 0 5 LSB
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(AVDD1 = AVDD2 = DVDD = DVDDO = 5V, AGND1 = DGND = DGNDO = AGND2 = AGND3 = 0, fCLK = 3.5MHz (50% duty cycle),
external clock mode, VREF = 4.096V (external reference operation), REFCAP = AVDD1, maximum single-ended bipolar input range
(±12V), CDOUT = 50pF, CSSTRB = 50pF, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN TYP MAX
UNITS
DYNAMIC SPECIFICATIONS fIN(SINE-WAVE) = 5kHz, VIN = FSR - 0.05dB, fSAMPLE = 130ksps (Notes 1, 2)
Differential inputs, FSR = 48V 85
Single-ended inputs, FSR = 24V 84
Single-ended inputs, FSR = 12V 83
Signal-to-Noise Plus Distortion SINAD
Single-ended inputs, FSR = 6V 79 81
dB
Differential inputs, FSR = 48V 85
Single-ended inputs, FSR = 24V 84
Single-ended inputs, FSR = 12V 83
Signal-to-Noise Ratio SNR
Single-ended inputs, FSR = 6V 81
dB
Total Harmonic Distortion
(Up to the 5th Harmonic) THD -97 dB
Spurious-Free Dynamic Range SFDR 92 99 dB
Aperture Delay tAD Figure 21 15 ns
Aperture Jitter tAJ Figure 21
100
ps
Channel-to-Channel Isolation
105
dB
CONVERSION RATE
External clock mode, Figure 2
114
External acquisition mode, Figure 3 84
Byte-Wide Throughput Rate
fSAMPLE
Internal clock mode, Figure 4
106
ksps
ANALOG INPUTS (CH0–CH3 MAX1033, CH0–CH7 MAX1032, AGND1)
Small-Signal Bandwidth All input ranges, VIN = 100mVP-P (Note 2) 2
MHz
Full-Power Bandwidth All input ranges, VIN = 4VP-P (Note 2)
700
kHz
R[2:1] = 001 -3 +3
R[2:1] = 010 -6 0
R[2:1] = 011 0 +6
R[2:1] = 100 -6 +6
R[2:1] = 101 -12 0
R[2:1] = 110 0
+12
Input Voltage Range (Table 6) VCH_
R[2:1] = 111 -12
+12
V
True-Differential Analog
Common-Mode Voltage Range VCMDR DIF/SGL = 1 (Note 4) -14 +9 V
Common-Mode Rejection Ratio CMRR DIF/SGL = 1, input voltage range = ±3V 75 dB
Input Current ICH_ -12V < VCH_ < +12V
-1250 +900
µA
Input Capacitance CCH_ 5pF
Input Resistance RCH_ 17 kΩ
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
4 _______________________________________________________________________________________
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
INTERNAL REFERENCE (Bypass REFCAP with 0.1µF to AGND1 and REF with 1.0µF to AGND1)
Reference Output Voltage VREF
4.056 4.096 4.136
V
Reference Temperature
Coefficient TCREF
±30
ppm/°C
REF shorted to AGND1 10
Reference Short-Circuit Current IREFSC REF shorted to AVDD -1 mA
Reference Load Regulation IREF = 0 to 0.5mA 0.1 10 mV
EXTERNAL REFERENCE (REFCAP = AVDD)
Reference Input Voltage Range VREF
3.800 4.136
V
REFCAP Buffer Disable
Threshold VRCTH (Note 5)
AVDD1
- 0.4
AVDD1
- 0.1
V
VREF = +4.096V, external clock mode,
external acquisition mode, internal clock
mode, or partial power-down mode
90
200
Reference Input Current IREF
VREF = +4.096V, full power-down mode
±0.1 ±10
µA
External clock mode, external acquisition
mode, internal clock mode, or partial
power-down mode
20 45
Reference Input Resistance RREF
Full power-down mode 40
kΩ
DIGITAL INPUTS (DIN, SCLK, CS)
Input High Voltage VIH 0.7 x
DVDDO
V
Input Low Voltage VIL 0.3 x
DVDDO
V
Input Hysteresis VHYST 0.2 V
Input Leakage Current IIN VIN = 0 to DVDDO -10
+10
µA
Input Capacitance CIN 10 pF
DIGITAL OUTPUTS (DOUT, SSTRB)
DVDDO = 4.75V, ISINK = 10mA 0.4
Output Low Voltage VOL DVDDO = 2.7V, ISINK = 5mA 0.4 V
Output High Voltage VOH ISOURCE = 0.5mA
DVDDO
- 0.4
V
DOUT Tri-State Leakage Current
IDDO CS = DVDDO -10
+10
µA
POWER REQUIREMENTS (AVDD1 and AGND1, AVDD2 and AGND2, DVDD and DGND, DVDDO and DGNDO)
Analog Supply Voltage AVDD1
4.75 5.25
V
Digital Supply Voltage DVDD
4.75 5.25
V
ELECTRICAL CHARACTERISTICS (continued)
(AVDD1 = AVDD2 = DVDD = DVDDO = 5V, AGND1 = DGND = DGNDO = AGND2 = AGND3 = 0, fCLK = 3.5MHz (50% duty cycle),
external clock mode, VREF = 4.096V (external reference operation), REFCAP = AVDD1, maximum single-ended bipolar input range
(±12V), CDOUT = 50pF, CSSTRB = 50pF, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
_______________________________________________________________________________________ 5
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Preamplifier Supply Voltage AVDD2
4.75 5.25
V
Digital I/O Supply Voltage DVDDO
2.70 5.25
V
Internal reference 3 3.5
AVDD1 Supply Current IAVDD1
External clock mode,
external acquisition
mode, or internal
clock mode External reference 2.5 3
mA
DVDD Supply Current IDVDD External clock mode, external acquisition
mode, or internal clock mode 0.9 2 mA
AVDD2 Supply Current IAVDD2 External clock mode, external acquisition
mode, or internal clock mode
17.5
25 mA
DVDDO Supply Current
IDVDDO
External clock mode, external acquisition
mode, or internal clock mode 0.2 1 mA
Partial power-down mode 1.3 mA
Total Supply Current Full power-down mode 1 µA
Power-Supply Rejection Ratio PSRR All analog input ranges
±0.125
LSB
TIMING CHARACTERISTICS (Figures 15 and 16)
External clock mode
272
62
External acquisition mode
228
62
SCLK Period tCP
Internal clock mode
100
83
µs
External clock mode
109
External acquisition mode 92
SCLK High Pulse Width (Note 6)
tCH
Internal clock mode 40
ns
External clock mode
109
External acquisition mode 92
SCLK Low Pulse Width (Note 6) tCL
Internal clock mode 40
ns
DIN to SCLK Setup tDS 40 ns
DIN to SCLK Hold tDH 0ns
SCLK Fall to DOUT Valid tDO 40 ns
CS Fall to DOUT Enable tDV 40 ns
CS Rise to DOUT Disable tTR 40 ns
CS Fall to SCLK Rise Setup tCSS 40 ns
CS High Minimum Pulse Width tCSPW 40 ns
SCLK Fall to CS Rise Hold tCSH 0ns
SSTRB Rise to CS Fall Setup (Note 4) 40 ns
DOUT Rise/Fall Time CL = 50pF 10 ns
SSTRB Rise/Fall Time CL = 50pF 10 ns
ELECTRICAL CHARACTERISTICS (continued)
(AVDD1 = AVDD2 = DVDD = DVDDO = 5V, AGND1 = DGND = DGNDO = AGND2 = AGND3 = 0, fCLK = 3.5MHz (50% duty cycle),
external clock mode, VREF = 4.096V (external reference operation), REFCAP = AVDD1, maximum single-ended bipolar input range
(±12V), CDOUT = 50pF, CSSTRB = 50pF, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
6 _______________________________________________________________________________________
Note 1: Parameter tested at AVDD1 = AVDD2 = DVDD = DVDDO = 5V.
Note 2: See definitions in the Parameter Definitions section at the end of the data sheet.
Note 3: Guaranteed by correlation with single-ended measurements.
Note 4: Not production tested. Guaranteed by design.
Note 5: To ensure external reference operation, VREFCAP must exceed (AVDD1 - 0.1V). To ensure internal reference operation, VREFCAP
must be below (AVDD1 - 0.4V). Bypassing REFCAP with a 0.1µF or larger capacitor to AGND1 sets VREFCAP ≈4.096V. The tran-
sition point between internal reference mode and external reference mode lies between the REFCAP buffer disable threshold
minimum and maximum values (Figures 17 and 18).
Note 6: The SCLK duty cycle can vary between 40% and 60%, as long as the tCL and tCH timing requirements are met.
ANALOG SUPPLY CURRENT
vs. ANALOG SUPPLY VOLTAGE
MAX1032/33 toc01
AVDD1 (V)
IAVDD1 (mA)
5.155.054.954.85
2.35
2.40
2.45
2.50
2.55
2.60
2.30
4.75 5.25
+85°C
+25°C
-40°C
EXTERNAL CLOCK MODE
PREAMPLIFIER SUPPLY CURRENT
vs. PREAMPLIFIER SUPPLY VOLTAGE
MAX1032/33 toc02
AVDD2 (V)
IAVDD2 (mA)
5.155.054.85 4.95
16
17
18
19
20
21
22
23
24
15
4.75 5.25
+85°C
+25°C
-40°C
EXTERNAL CLOCK MODE
DIGITAL SUPPLY CURRENT
vs. DIGITAL SUPPLY VOLTAGE
MAX1032/33 toc03
DVDD (V)
IDVDD (mA)
5.155.054.954.85
0.70
0.75
0.80
0.85
0.90
0.65
4.75 5.25
+85°C
+25°C
-40°C
EXTERNAL CLOCK MODE
Typical Operating Characteristics
(AVDD1 = AVDD2 = DVDD = DVDDO = 5V, AGND1 = DGND = DGNDO = AGND2 = AGND3 = 0, fCLK = 3.5MHz (50% duty cycle),
external clock mode, VREF = 4.096V (external reference operation), REFCAP = AVDD1, maximum single-ended bipolar input range
(±12V), CDOUT = 50pF, CSSTRB = 50pF; unless otherwise noted.)
ELECTRICAL CHARACTERISTICS (continued)
(AVDD1 = AVDD2 = DVDD = DVDDO = 5V, AGND1 = DGND = DGNDO = AGND2 = AGND3 = 0, fCLK = 3.5MHz (50% duty cycle),
external clock mode, VREF = 4.096V (external reference operation), REFCAP = AVDD1, maximum single-ended bipolar input range
(±12V), CDOUT = 50pF, CSSTRB = 50pF, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
_______________________________________________________________________________________ 7
DIGITAL I/O SUPPLY CURRENT
vs. DIGITAL I/O SUPPLY VOLTAGE
MAX1032/33 toc04
DVDDO (V)
IDVDDO (mA)
5.155.054.85 4.95
0.12
0.14
0.16
0.18
0.20
0.22
0.24
0.26
0.28
0.10
4.75 5.25
+85°C
+25°C
-40°C
EXTERNAL CLOCK MODE
ANALOG SUPPLY CURRENT
vs. ANALOG SUPPLY VOLTAGE
MAX1032/33 toc05
AVDD1 (V)
IAVDD1 (mA)
5.155.054.954.85
0.47
0.49
0.51
0.53
0.55
0.45
4.75 5.25
+85°C
+25°C
-40°C
PARTIAL POWER-DOWN MODE
Typical Operating Characteristics (continued)
(AVDD1 = AVDD2 = DVDD = DVDDO = 5V, AGND1 = DGND = DGNDO = AGND2 = AGND3 = 0, fCLK = 3.5MHz (50% duty cycle),
external clock mode, VREF = 4.096V (external reference operation), REFCAP = AVDD1, maximum single-ended bipolar input range
(±12V), CDOUT = 50pF, CSSTRB = 50pF; unless otherwise noted.)
PREAMPLIFIER SUPPLY CURRENT
vs. PREAMPLIFIER SUPPLY VOLTAGE
MAX1032/33 toc06
AVDD2 (V)
IAVDD2 (mA)
5.155.054.954.85
0.12
0.14
0.16
0.18
0.20
0.10
4.75 5.25
+85°C
+25°C
-40°C
PARTIAL POWER-DOWN MODE
DIGITAL SUPPLY CURRENT
vs. DIGITAL SUPPLY VOLTAGE
MAX1032/33 toc07
DVDD (V)
IDVDD (mA)
5.154.85 5.054.95
0.122
0.124
0.126
0.128
0.130
0.132
0.134
0.136
0.120
4.75 5.25
PARTIAL POWER-DOWN MODE
+85°C
+25°C
-40°C
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
8 _______________________________________________________________________________________
ANALOG SUPPLY CURRENT
vs. CONVERSION RATE
MAX1032/33 toc08
CONVERSION RATE (ksps)
IAVDD1 (mA)
20015010050
0.5
1.0
1.5
2.0
2.5
3.0
0
0
EXTERNAL CLOCK MODE
PARTIAL
POWER-DOWN MODE
FULL
POWER-DOWN MODE
PREAMPLIFIER SUPPLY CURRENT
vs. CONVERSION RATE
MAX1032/33 toc09
IAVDD2 (mA)
5
10
15
20
25
0
CONVERSION RATE (ksps)
200
150100500
fCLK = 7.5MHz (NOTE 6)
EXTERNAL CLOCK MODE
FULL POWER-DOWN MODE,
PARTIAL POWER-DOWN MODE
Typical Operating Characteristics (continued)
(AVDD1 = AVDD2 = DVDD = DVDDO = 5V, AGND1 = DGND = DGNDO = AGND2 = AGND3 = 0, fCLK = 3.5MHz (50% duty cycle),
external clock mode, VREF = 4.096V (external reference operation), REFCAP = AVDD1, maximum single-ended bipolar input range
(±12V), CDOUT = 50pF, CSSTRB = 50pF; unless otherwise noted.)
DIGITAL SUPPLY CURRENT
vs. CONVERSION RATE
MAX1032/33 toc10
IDVDD (mA)
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
0
0
CONVERSION RATE (ksps)
200
15010050
fCLK = 7.5MHz (NOTE 6)
FULL POWER-DOWN MODE
EXTERNAL CLOCK MODE,
PARTIAL POWER-DOWN MODE
DIGITAL I/O SUPPLY CURRENT
vs. CONVERSION RATE
MAX1032/33 toc11
CONVERSION RATE (ksps)
IDVDDO (mA)
20015010050
0.1
0.2
0.3
0.4
0.5
0.6
0
0
fCLK = 7.5MHz (NOTE 6)
EXTERNAL CLOCK MODE
FULL POWER-DOWN MODE,
PARTIAL POWER-DOWN MODE
Note 6: For partial power-down and full power-down modes, external clock mode was used for a burst of continuous samples.
Partial power-down or full power-down modes were entered thereafter. By using this method, the conversion rate was found
by averaging the number of conversions over the time starting from the first conversion to the end of the partial power-down
or full power-down modes.
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
_______________________________________________________________________________________ 9
EXTERNAL REFERENCE INPUT CURRENT
vs. EXTERNAL REFERENCE INPUT VOLTAGE
MAX1032/33 toc12
EXTERNAL REFERENCE VOLTAGE (V)
EXTERNAL REFERENCE CURRENT (mA)
4.104.054.003.953.903.85
0.13
0.14
0.15
0.16
0.12
3.80 4.15
ALL MODES
GAIN DRIFT vs. TEMPERATURE
MAX1032/33 toc13
TEMPERATURE (°C)
GAIN ERROR (%FSR)
603510-15
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.10
-0.10
-40 85
±12V BIPOLAR RANGE
±3V BIPOLAR RANGE
OFFSET DRIFT vs. TEMPERATURE
MAX1032/33 toc14
TEMPERATURE (°C)
OFFSET ERROR (mV)
603510-15
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1.0
-1.0
-40 85
±3V BIPOLAR
±12V BIPOLAR
CHANNEL-TO-CHANNEL ISOLATION
vs. INPUT FREQUENCY
MAX1032/33 toc15
FREQUENCY (kHz)
ISOLATION (dB)
100010010
-100
-80
-60
-40
-20
0
-120
1 10,000
fSAMPLE = 115ksps
±12V BIPOLAR RANGE
CH0 TO CH2
COMMON-MODE REJECTION RATIO
vs. FREQUENCY
MAX1032/33 toc16
FREQUENCY (kHz)
CMRR (dB)
100010010
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
-100
1 10,000
fSAMPLE = 115ksps
±12V BIPOLAR RANGE
INTEGRAL NONLINEARITY
vs. DIGITAL OUTPUT CODE
MAX1032/33 toc17
DIGITAL OUTPUT CODE
INL (LSB)
12,28881924096
-0.5
0
0.5
1.0
-1.0
0 16,383
fSAMPLE = 115ksps
±12V BIPOLAR RANGE
DIFFERENTIAL NONLINEARITY
vs. DIGITAL OUTPUT CODE
MAX1032 toc18
DIGITAL OUTPUT CODE
DNL (LSB)
12,2884096 8192
-0.5
0
0.5
1.0
-1.0
0 16,383
fSAMPLE = 115ksps
±12V BIPOLAR RANGE
FFT AT 5kHz
MAX1032/33 toc19
FREQUENCY (kHz)
MAGNITUDE (dB)
5040302010
-120
-100
-80
-60
-40
-20
0
-140
0
fSAMPLE = 115ksps
fIN(SINE WAVE) = 5kHz
±12V BIPOLAR RANGE
Typical Operating Characteristics (continued)
(AVDD1 = AVDD2 = DVDD = DVDDO = 5V, AGND1 = DGND = DGNDO = AGND2 = AGND3 = 0, fCLK = 3.5MHz (50% duty cycle),
external clock mode, VREF = 4.096V (external reference operation), REFCAP = AVDD1, maximum single-ended bipolar input range
(±12V), CDOUT = 50pF, CSSTRB = 50pF; unless otherwise noted.)
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
10 ______________________________________________________________________________________
SNR, SINAD, ENOB
vs. ANALOG INPUT FREQUENCY
MAX1032/33 toc20
FREQUENCY (kHz)
SNR, SINAD (dB)
10010
10
20
30
40
50
60
70
80
90
100
0
1 1000
ENOB (BITS)
7
8
9
10
11
12
13
14
15
16
6
ENOB
SINAD
SNR
fSAMPLE = 115ksps
±12V BIPOLAR RANGE
SNR, SINAD, ENOB vs. SAMPLE RATE
MAX1032/33 toc21
SAMPLE RATE (ksps)
SNR, SINAD (dB)
100101
20
40
60
80
100
0
0.1 1000
fIN(SINE WAVE) = 5kHz
±12V BIPOLAR RANGE
ENOB (BITS)
8
10
12
14
16
6
ENOB
SNR, SINAD
-SFDR, THD vs. SAMPLE RATE
MAX1032/33 toc22
SAMPLE RATE (ksps)
-SFDR, THD (dB)
100101
-100
-80
-60
-40
-20
0
-120
0.1 1000
fIN(SINE WAVE) = 5kHz
±12V BIPOLAR RANGE
THD
-SFDR
-SFDR, THD
vs. ANALOG INPUT FREQUENCY
MAX1032/33 toc23
FREQUENCY (kHz)
-SFDR, THD (dB)
10010
-100
-80
-60
-40
-20
0
-120
1 1000
fSAMPLE = 115kHz
±12V BIPOLAR RANGE
THD
-SFDR
ANALOG INPUT CURRENT
vs. ANALOG INPUT VOLTAGE
MAX1032/33 toc24
ANALOG INPUT VOLTAGE (V)
ANALOG INPUT CURRENT (mA)
9630-3-6-9
-0.6
-0.2
0.2
0.6
1.0
-1.0
-12 12
ALL MODES
SMALL-SIGNAL BANDWIDTH
MAX1032/33 toc25
FREQUENCY (kHz)
ATTENUATION (dB)
100010010
-40
-35
-30
-25
-20
-15
-10
-5
0
-45
1 10,000
Typical Operating Characteristics (continued)
(AVDD1 = AVDD2 = DVDD = DVDDO = 5V, AGND1 = DGND = DGNDO = AGND2 = AGND3 = 0, fCLK = 3.5MHz (50% duty cycle),
external clock mode, VREF = 4.096V (external reference operation), REFCAP = AVDD1, maximum single-ended bipolar input range
(±12V), CDOUT = 50pF, CSSTRB = 50pF; unless otherwise noted.)
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
______________________________________________________________________________________ 11
FULL-POWER BANDWIDTH
MAX1032/33 toc26
FREQUENCY (kHz)
ATTENUATION (dB)
100010010
-40
-35
-30
-25
-20
-15
-10
-5
0
-45
1 10,000
REFERENCE VOLTAGE vs. TIME
MAX1032/33 toc27
1V/div
0V
4ms/div
NOISE HISTOGRAM
(CODE CENTER)
MAX1032/33 toc28
CODE
NUMBER OF HITS
8193
10,000
20,000
30,000
40,000
50,000
60,000
70,000
0
8191 8195 8197
65,534 SAMPLES
8192 8194 8196
NOISE HISTOGRAM
(CODE EDGE)
MAX1032/33 toc29
CODE
NUMBER OF HITS
8194
5000
10,000
15,000
20,000
25,000
30,000
35,000
0
65,534
SAMPLES
81958193 8196 81978192
Typical Operating Characteristics (continued)
(AVDD1 = AVDD2 = DVDD = DVDDO = 5V, AGND1 = DGND = DGNDO = AGND2 = AGND3 = 0, fCLK = 3.5MHz (50% duty cycle),
external clock mode, VREF = 4.096V (external reference operation), REFCAP = AVDD1, maximum single-ended bipolar input range
(±12V), CDOUT = 50pF, CSSTRB = 50pF; unless otherwise noted.)
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
12 ______________________________________________________________________________________
Pin Description
PIN
MAX1032
MAX1033
NAME FUNCTION
12AV
DD1 Analog Supply Voltage 1. Connect AVDD1 to a +4.75V to +5.25V power-supply voltage.
Bypass AVDD1 to AGND1 with a 0.1µF capacitor.
2 3 CH0 Analog Input Channel 0
3 4 CH1 Analog Input Channel 1
4 5 CH2 Analog Input Channel 2
5 6 CH3 Analog Input Channel 3
6 — CH4 Analog Input Channel 4
7 — CH5 Analog Input Channel 5
8 — CH6 Analog Input Channel 6
9 — CH7 Analog Input Channel 7
10 7 CS
Active-Low Chip-Select Input. When CS is low, data is clocked into the device from DIN on
the rising edge of SCLK. With CS low, data is clocked out of DOUT on the falling edge of
SCLK. When CS is high, activity on SCLK and DIN is ignored and DOUT is high impedance.
11 8 DIN Serial Data Input. When CS is low, data is clocked in on the rising edge of SCLK. When CS is
high, transitions on DIN are ignored.
12 9 SSTRB
Serial-Strobe Output. When using the internal clock, SSTRB rising edge transitions indicate
that data is ready to be read from the device. When operating in external clock mode, SSTRB
is always low. SSTRB does not tri-state, regardless of the state of CS, and therefore requires
a dedicated I/O line.
13 10 SCLK Serial Clock Input. When CS is low, transitions on SCLK clock data into DIN and out of DOUT.
When CS is high, transitions on SCLK are ignored.
14 11 DOUT Serial Data Output. When CS is low, data is clocked out of DOUT with each falling SCLK
transition. When CS is high, DOUT is high impedance.
15 12
DGNDO
D i gi tal I/O Gr ound . D GND , DGN D O, AGN D 3, AGND 2, and AGN D1 m ust be connected tog ether.
16 13 DGND
Digital Ground. DGND, DGNDO, AGND3, AGND2, and AGND1 must be connected together.
17 14 DVDDO Digital I/O Supply Voltage Input. Connect DVDDO to a +2.7V to +5.25V power-supply voltage.
Bypass DVDDO to DGNDO with a 0.1µF capacitor.
18 15 DVDD Digital-Supply Voltage Input. Connect DVDD to a +4.75V to +5.25V power-supply voltage.
Bypass DVDD to DGND with a 0.1µF capacitor.
19 16
REFCAP
Bandgap-Voltage Bypass Node. For external reference operation, connect REFCAP to AVDD.
For internal reference operation, bypass REFCAP with a 0.01µF capacitor to AGND1
(VREFCAP ≈ 4.096V).
20 17 REF
Reference-Buffer Output/ADC Reference Input. For external reference operation, apply an
external reference voltage from 3.800V to 4.136V to REF. For internal reference operation,
bypassing REF with a 1µF capacitor to AGND1 sets VREF = 4.096V ±1%.
Detailed Description
The MAX1032/MAX1033 multirange, low-power, 14-bit
successive-approximation ADCs operate from a single
+5V supply and have a separate digital supply allowing
digital interface with 2.7V to 5.25V systems. These 14-bit
ADCs have internal track-and-hold (T/H) circuitry that
supports single-ended and fully differential inputs. For
single-ended conversions, the valid analog input voltage
range spans from -12V below ground to +12V above
ground. The maximum allowable differential input volt-
age spans from -24V to +24V. Data can be converted in
a variety of software-programmable channel and data-
acquisition configurations. Microprocessor (µP) control is
made easy through an SPI-/QSPI-/MICROWIRE-compati-
ble serial interface.
The MAX1032 has eight single-ended analog input
channels or four differential channels (see the Block
Diagram at the end of the data sheet). The MAX1033 has
four single-ended analog input channels or two differen-
tial channels. Each analog input channel is independently
software programmable for seven single-ended input
ranges (0 to +6V, -6V to 0, 0 to +12V, -12V to 0, ±3V,
±6V, and ±12V) and three differential input ranges (±6V,
±12V, and ±24V). Additionally, all analog input channels
are fault tolerant to ±16.5V. A fault condition on an idle
channel does not affect the conversion result of other
channels.
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
______________________________________________________________________________________ 13
Pin Description (continued)
PIN
MAX1032
MAX1033
NAME FUNCTION
21 18
AGND3
Analog Signal Ground 3. AGND3 is the ADC negative reference potential. Connect AGND3 to
AGND1. DGND, DGNDO, AGND3, AGND2, and AGND1 must be connected together.
22 19 AVDD2 Analog Supply Voltage 2. Connect AVDD2 to a +4.75V to +5.25V power-supply voltage.
Bypass AVDD2 to AGND2 with a 0.1µF capacitor.
23 20
AGND2
Analog Ground 2. This ground carries approximately five times more current than AGND1.
DGND, DGNDO, AGND3, AGND2, and AGND1 must be connected together.
24 1
AGND1
Anal og Gr ound 1. D GN D , D GN DO, AGN D 3, AGN D 2, and AGND 1 must b e connected together .
4–20mA
PLC
ACCELERATION
PRESSURE
TEMPERATURE
WHEATESTONE
WHEATESTONE
1µF
0.1µFAGND2 DGNDOAGND3 DGND
AVDD2 DVDD
AVDD1
0.1µF 0.1µF 0.1µF
5.0V 5.0V 5.0V
MAX1032
CHO
CH1
CH2
CH3
CH4
CH5
CH6
CH7
REF
AGND1
REFCAP
0.1µF
3.3V
MC68HCXX
µC
DVDDO
SCLK
CS
DIN
SSTRB
DOUT
VDD
SCK
I/O
MOSI
I/O
MISO
VSS
Figure 1. Typical Application Circuit
MAX1032/MAX1033
Power Supplies
To maintain a low-noise environment, the MAX1032/
MAX1033 provide separate power supplies for each
section of circuitry. Table 1 shows the four separate
power supplies. Achieve optimal performance using
separate AVDD1, AVDD2, DVDD, and DVDDO supplies.
Alternatively, connect AVDD1, AVDD2, and DVDD
together as close to the device as possible for a conve-
nient power connection. Connect AGND1, AGND2,
AGND3, DGND, and DGNDO together as close to the
device as possible. Bypass each supply to the corre-
sponding ground using a 0.1µF capacitor (Table 1). If
significant low-frequency noise is present, add a 10µF
capacitor in parallel with the 0.1µF bypass capacitor.
Converter Operation
The MAX1032/MAX1033 ADCs feature a fully differen-
tial, successive-approximation register (SAR) conver-
sion technique and an on-chip T/H block to convert
voltage signals into a 14-bit digital result. Both single-
ended and differential configurations are supported
with programmable unipolar and bipolar signal ranges.
Track-and-Hold Circuitry
The MAX1032/MAX1033 feature a switched-capacitor
T/H architecture that allows the analog input signal to be
stored as charge on sampling capacitors. See Figures 2,
3, and 4 for T/H timing and the sampling instants for
each operating mode. The MAX1032/MAX1033 analog
input circuitry buffers the input signal from the sampling
capacitors, resulting in a constant analog input current
with varying input voltage (Figure 5).
Analog Input Circuitry
Select differential or single-ended conversions using the
associated analog input configuration byte (Table 2).
The analog input signal source must be capable of dri-
ving the ADC’s 17kΩinput resistance (Figure 6).
Figure 6 shows the simplified analog input circuit. The
analog inputs are ±16.5V fault tolerant and are protect-
ed by back-to-back diodes. The summing junction volt-
age, VSJ, is a function of the channel’s input common-
mode voltage:
VR
RR VR
RR V
SJ CM
. =+
⎛
⎝
⎜⎞
⎠
⎟×++
+
⎛
⎝
⎜⎞
⎠
⎟
⎛
⎝
⎜⎞
⎠
⎟×
1
122 375 1 1
12
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
14 ______________________________________________________________________________________
Table 1. MAX1032/MAX1033 Power Supplies and Bypassing
POWER
SUPPLY/GROUND
SUPPLY VOLTAGE
RANGE (V)
TYPICAL SUPPLY
CURRENT (mA)
CIRCUIT SECTION BYPASSING
DVDDO/DGNDO 2.7 to 5.25 0.2 Digital I/O 0.1µF to DGNDO
AVDD2/AGND2 4.75 to 5.25 17.5 Analog Circuitry 0.1µF to AGND2
AVDD1/AGND1 4.75 to 5.25 3.0 Analog Circuitry 0.1µF to AGND1
DVDD/DGND 4.75 to 5.25 0.9 Digital Control Logic and
Memory 0.1µF to DGND
Table 2. Analog Input Configuration Byte
BIT
NUMBER
NAME DESCRIPTION
7 START Start Bit. The first logic 1 after CS goes low defines the beginning of the analog input configuration byte.
6C2
5C1
4C0
Channel-Select Bits. SEL[2:0] select the analog input channel to be configured (Tables 4 and 5).
3
DIF/SGL
Differential or Single-Ended Configuration Bit. DIF/SGL = 0 configures the selected analog input channel
for single-ended operation. DIF/SGL = 1 configures the channel for differential operation. In single-ended
mode, input voltages are measured between the selected input channel and AGND1, as shown in
Table 4. In differential mode, the input voltages are measured between two input channels, as shown in
Table 5. Be aware that changing DIF/SGL adjusts the FSR, as shown in Table 6.
2R2
1R1
0R0
Input-Range-Select Bits. R[2:0] select the input voltage range, as shown in Table 6 and Figure 7.
As a result, the analog input impedance is relatively
constant over input voltage as shown in Figure 5.
Single-ended conversions are internally referenced to
AGND1 (Tables 3 and 4). In differential mode, IN+ and
IN- are selected according to Tables 3 and 5. When con-
figuring differential channels, the differential pair follows
the analog configuration byte for the positive channel.
For example, to configure CH2 and CH3 for a ±12V dif-
ferential conversion, set the CH2 analog configuration
byte for a differential conversion with the ±12V range
(1010 1100). To initiate a conversion for the CH2 and
CH3 differential pair, issue the command 1010 0000.
Analog Input Bandwidth
The MAX1032/MAX1033 input-tracking circuitry has a
2MHz small-signal bandwidth. The 2MHz input band-
width makes it possible to digitize high-speed transient
events. Harmonic distortion increases when digitizing
signal frequencies above 15kHz as shown in the THD
and -SFDR vs. Input Frequency plot in the Typical
Operating Characteristics.
Analog Input Range and Fault Tolerance
Figure 7 illustrates the software-selectable single-
ended analog input voltage range that produces a valid
digital output. Each analog input channel can be inde-
pendently programmed to one of seven single-ended
input ranges by setting the R[2:0] control bits with
DIF/SGL = 0.
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
______________________________________________________________________________________ 15
CS
SCLK
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
DIN S C2 C1 C0 0 0 0 0
ANALOG INPUT
TRACK AND HOLD*
DOUT
B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0 X X
BYTE 1 BYTE 2 BYTE 3 BYTE 4
SSTRB
HOLD TRACK HOLD
HIGH
IMPEDANCE
HIGH
IMPEDANCE
tACQ
*TRACK AND HOLD TIMING IS CONTROLLED BY SCLK.
fSAMPLE ≈ fSCLK / 32
SAMPLING INSTANT
Figure 2. External Clock-Mode Conversion (Mode 0)
MAX1032/MAX1033
Figure 8 illustrates the software-selectable differential
analog input voltage range that produces a valid digital
output. Each analog input differential pair can be inde-
pendently programmed to one of three differential input
ranges by setting the R[2:0] control bits with DIF/SGL = 1.
Regardless of the specified input voltage range and
whether the channel is selected, each analog input is
±16.5V fault tolerant. The analog input fault protection
is active whether the device is unpowered or powered.
Any voltage beyond FSR, but within the ±16.5V fault-
tolerant range, applied to an analog input results in a
full-scale output voltage for that channel.
Clamping diodes with breakdown thresholds in excess
of 16.5V protect the MAX1032/MAX1033 analog inputs
during ESD and other transient events (Figure 6). The
clamping diodes do not conduct during normal device
operation, nor do they limit the current during such
transients. When operating in an environment with the
potential for high-energy voltage and/or current tran-
sients, protect the MAX1032/MAX1033 externally.
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
16 ______________________________________________________________________________________
CS
SCLK
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
DIN SC2C1C00000
ANALOG INPUT
TRACK AND HOLD* HOLD
DOUT
B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0 X X
BYTE 1 BYTE 2 BYTE 3 BYTE 4
SSTRB
INTCLK**
1
2
3
14
15
16
17
TRACK HOLD
tACQ
100ns to 400ns
fINTCLK ≈ 4.5MHz
fSAMPLE ≈ fSCLK / 32 + fINTCLK / 17
*TRACK AND HOLD TIMING IS CONTROLLED BY SCLK.
**INTCLK IS AN INTERNAL SIGNAL AND IS NOT ACCESSIBLE TO THE USER.
SAMPLING INSTANT
HIGH
IMPEDANCE
Figure 3. External Acquisition-Mode Conversion (Mode 1)
Figure 6. Simplified Analog Input Circuit
MAX1032
MAX1033
R2
R1
VSJ
*RSOURCE
ANALOG
SIGNAL
SOURCE
R2
R1
VSJ
*RSOURCE
ANALOG
SIGNAL
SOURCE
IN_+
IN_+
*MINIMIZE RSOURCE TO AVOID GAIN ERROR AND DISTORTION.
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
______________________________________________________________________________________ 17
CS
SCLK
1
2
3
4
5
6
7
8
17
18
19
20
21
22
23
24
DIN S C2 C1 C0 0 0 0 0
ANALOG INPUT
TRACK AND HOLD* TRACK
DOUT
B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0 X X
BYTE 1 BYTE 2 BYTE 3
SSTRB
INTCLK**
1
2
3
25
26
27
28
9
10
11
12
13
14
15
16
10
11
12
13
14
HOLD HOLD
tACQ
100ns to 400ns
fINTCLK ≈ 4.5MHz
fSAMPLE ≈ fSCLK / 24 + fINTCLK / 28
*TRACK AND HOLD TIMING IS CONTROLLED BY INTCLK, AND IS NOT ACCESSIBLE TO THE USER.
**INTCLK IS AN INTERNAL SIGNAL AND IS NOT ACCESSIBLE TO THE USER.
SAMPLING INSTANT
HIGH
IMPEDANCE
Figure 4. Internal Clock-Mode Conversion (Mode 2)
ANALOG INPUT VOLTAGE (V)
ANALOG INPUT CURRENT (mA)
9630-3-6-9
-0.6
-0.2
0.2
0.6
1.0
-1.0
-12 12
ALL MODES
Figure 5. Analog Input Current vs. Input Voltage
Differential Common-Mode Range
The MAX1032/MAX1033 differential common-mode
range (VCMDR) must remain within -14V to +9V to
obtain valid conversion results. The differential com-
mon-mode range is defined as:
In addition to the common-mode input voltage limita-
tions, each individual analog input must be limited to
±16.5V with respect to AGND1.
The range-select bits R[2:0] in the analog input config-
uration bytes determine the full-scale range for the cor-
responding channel (Tables 2 and 6). Figures 9, 10,
and 11 show the valid analog input voltage ranges for
the MAX1032/MAX1033 when operating with FSR =
12V, FSR = 24V, and FSR = 48V, respectively. The
shaded area contains the valid common-mode voltage
ranges that support the entire FSR.
VCH CH
CMDR _ _
=+
()
+
()
−
2
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
18 ______________________________________________________________________________________
Table 3. Input Data Word Formats
DATA BIT
OPERATION D7
(START)
D6 D5 D4 D3 D2 D1 D0
Conversion-Start Byte
(Tables 4 and 5) 1C2C1C00000
Analog-Input Configuration Byte
(Table 2) 1C2C1C0
DIF/SGL
R2 R1 R0
Mode-Control Byte
(Table 7) 1M2M1M01000
Table 4. Channel Selection in Single-Ended Mode (DIF/SGL = 0)
CHANNEL-SELECT BIT CHANNEL
C2 C1 C0 CH0 CH1 CH2 CH3 CH4 CH5 CH6 CH7
AGND1
000+ -
001 + -
010 + -
011 + -
100 + -
101 + -
110 +-
111 +-
Table 5. Channel Selection in True-Differential Mode (DIF/SGL = 1)
CHANNEL-SELECT BIT CHANNEL
C2 C1 C0 CH0 CH1 CH2 CH3 CH4 CH5 CH6 CH7
AGND1
000+-
0 0 1 RESERVED
010 +-
0 1 1 RESERVED
100 +-
1 0 1 RESERVED
110 +-
1 1 1 RESERVED
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
______________________________________________________________________________________ 19
001
010
011
100
101
110
111
0
-6
-9
-12
+12
+9
+6
+3
-3
EACH INPUT IS FAULT TOLERANT TO ±16.5V.
VREF = 4.096V.
(CH_) - AGND1 (V)
INPUT RANGE SELECTION BITS, R[2:0]
FSR = 6V
FSR = 6V
FSR = 6V
FSR = 12V
FSR = 12V
FSR = 12V
FSR = 24V
Figure 7. Single-Ended Input Voltage Ranges
001
010
011
100
101
110
111
-12
-18
-24
+24
+18
+12
+6
-6
EACH INPUT IS FAULT TOLERANT TO ±16.5V.
VREF = 4.096V.
(CH_+) - (CH_-) (V)
INPUT RANGE SELECTION BITS, R[2:0]
0
FSR = 12V
FSR = 24V
FSR = 48V
Figure 8. Differential Input Voltage Ranges
Digital Interface
The MAX1032/MAX1033 feature a serial interface that is
compatible with SPI/QSPI and MICROWIRE devices.
DIN, DOUT, SCLK, CS, and SSTRB facilitate bidirec-
tional communication between the MAX1032/MAX1033
and the master at SCLK rates up to 10MHz (internal
clock mode, mode 2), 3.67MHz (external clock mode,
mode 0), or 4.39MHz (external acquisition mode, mode
1). The master, typically a microcontroller, should use
the CPOL = 0, CPHA = 0, SPI transfer format, as shown
in the timing diagrams of Figures 2, 3, and 4.
The digital interface is used to:
• Select single-ended or true-differential input channel
configurations
• Select the unipolar or bipolar input range
• Select the mode of operation:
External clock (mode 0)
External acquisition (mode 1)
Internal clock (mode 2)
Reset (mode 4)
Partial power-down (mode 6)
Full power-down (mode 7)
• Initiate conversions and read results
Chip Select (
CS
)
CS enables communication with the MAX1032/MAX1033.
When CS is low, data is clocked into the device from DIN
on the rising edge of SCLK and data is clocked out of
DOUT on the falling edge of SCLK. When CS is high,
activity on SCLK and DIN is ignored and DOUT is high
impedance allowing DOUT to be shared with other
peripherals. SSTRB is never high impedance and there-
fore cannot be shared with other peripherals.
Serial-Strobe Output (SSTRB)
As shown in Figures 3 and 4, the SSTRB transitions high
to indicate that the ADC has completed a conversion
and results are ready to be read by the master. SSTRB
remains low in the external clock mode (Figure 2) and
consequently may be left unconnected. SSTRB is dri-
ven high or low regardless of the state of CS, therefore
SSTRB cannot be shared with other peripherals.
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
20 ______________________________________________________________________________________
Table 6. Range-Select Bits
DIF/SGL R2 R1 R0 MODE TRANSFER FUNCTION
0 0 0 0 No Range Change* —
0001
Single-Ended
Bipolar -3V to +3V
Full-Scale Range (FSR) = 6V
Figure 12
0010
Single-Ended
Unipolar -6V to 0
FSR = 6V
Figure 13
0011
Single-Ended
Unipolar 0 to +6V
FSR = 6V
Figure 14
0100
Single-Ended
Bipolar -6V to +6V
FSR = 12V
Figure 12
0101
Single-Ended
Unipolar -12V to 0
FSR = 12V
Figure 13
0110
Single-Ended
Unipolar 0 to +12V
FSR = 12V
Figure 14
0111
DEFAULT SETTING
Single-Ended
Bipolar -12V to +12V
FSR = 24V
Figure 12
1 0 0 0 No Range Change** —
1001
Differential
Bipolar -6V to +6V
FSR = 12V
Figure 12
1 0 1 0 Reserved —
1 0 1 1 Reserved —
1100
Differential
Bipolar -12V to +12V
FSR = 24V
Figure 12
1 1 0 1 Reserved —
1 1 1 0 Reserved —
1111
Differential
Bipolar -24V to +24V
FSR = 48V
Figure 12
*Conversion-Start Byte (see Table 3).
**Mode-Control Byte (see Table 3).
Start Bit
Communication with the MAX1032/MAX1033 is accom-
plished using the three input data word formats shown
in Table 3. Each input data word begins with a start bit.
The start bit is defined as the first high bit clocked into
DIN with CS low when any of the following are true:
• Data conversion is not in process and all data from
the previous conversion has clocked out of DOUT.
• The device is configured for operation in external
clock mode (mode 0) and previous conversion-result
bits B13–B1 have clocked out of DOUT.
• The device is configured for operation in external
acquisition mode (mode 1) and previous conversion-
result bits B13–B5 have clocked out of DOUT.
• The device is configured for operation in internal
clock mode, (mode 2) and previous conversion-
result bits B13–B2 have clocked out of DOUT.
Output Data Format
Output data is clocked out of DOUT in offset binary for-
mat on the falling edge of SCLK, MSB first (B13). For
output binary codes, see the Transfer Function section
and Figures 12, 13, and 14.
Configuring Analog Inputs
Each analog input has two configurable parameters:
• Single-ended or true-differential input
• Input voltage range
These parameters are configured using the analog input
configuration byte as shown in Table 2. Each analog
input has a dedicated register to store its input configura-
tion information. The timing diagram of Figure 15 shows
how to write to the analog input configuration registers.
Figure 16 shows DOUT and SSTRB timing.
Transfer Function
An ADC’s transfer function defines the relationship
between the analog input voltage and the digital output
code. Figures 12, 13, and 14 show the MAX1032/
MAX1033 transfer functions. The transfer function is
determined by the following characteristics:
• Analog input voltage range
• Single-ended or differential configuration
• Reference voltage
The axes of an ADC transfer function are typically in least
significant bits (LSBs). For the MAX1032/MAX1033, an
LSB is calculated using the following equation:
where N is the number of bits (N = 14) and FSR is the
full-scale range (see Figures 7 and 8).
1
2 4 096
.
LSB FSR V
V
REF
N
=×
×
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
______________________________________________________________________________________ 21
INPUT VOLTAGE (V)
COMMON-MODE VOLTAGE (V)
1260-6-12
-12
-8
-4
0
4
8
12
-16
-18 18
Figure 9. Common-Mode Voltage vs. Input Voltage (FSR = 12V)
INPUT VOLTAGE (V)
COMMON-MODE VOLTAGE (V)
1260-6-12
-12
-8
-4
0
4
8
12
-16
-18 18
Figure 10. Common-Mode Voltage vs. Input Voltage (FSR = 24V)
INPUT VOLTAGE (V)
COMMON-MODE VOLTAGE (V)
1260-6-12
-12
-8
-4
0
4
8
12
-16
-18 18
Figure 11. Common-Mode Voltage vs. Input Voltage (FSR = 48V)
Mode Control
The MAX1032/MAX1033 contain one byte-wide mode-
control register. The timing diagram of Figure 15 shows
how to use the mode-control byte, and the mode-con-
trol byte format is shown in Table 7. The mode-control
byte is used to select the conversion method and to
control the power modes of the MAX1032/MAX1033.
Selecting the Conversion Method
The conversion method is selected using the mode-
control byte (see the Mode Control section), and the con-
version is initiated using a conversion-start command
(Table 3, and Figures 2, 3, and 4).The MAX1032/
MAX1033 convert analog signals to digital data using one
of three methods:
• External Clock Mode, Mode 0 (Figure 2)
• Highest maximum throughput (see the Electrical
Characteristics table)
• User controls the sample instant
•CS remains low during the conversion
• User supplies SCLK throughout the ADC con-
version and reads data at DOUT
• External Acquisition Mode, Mode 1 (Figure 3)
• Lowest maximum throughput (see the Electrical
Characteristics table)
• User controls the sample instant
• User supplies two bytes of SCLK, then drives
CS high to relieve processor load while the
ADC converts
• After SSTRB transitions high, the user supplies
two bytes of SCLK and reads data at DOUT
• Internal Clock Mode, Mode 2 (Figure 4)
• High maximum throughput (see the Electrical
Characteristics table)
• The internal clock controls the sampling instant
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
22 ______________________________________________________________________________________
1 LSB = FSR x VREF
16,384 x 4.096V
BINARY OUTPUT CODE (LSB [hex])
3FFF
3FFE
3FFD
2001
2000
1FFF
0003
0002
0001
0000
FSR
0 1 2 3 8,192 16,381 16,383
INPUT VOLTAGE (LSB [DECIMAL])
(AGND1)
FSR
Figure 13. Ideal Unipolar Transfer Function, Single-Ended
Input, -FSR to 0
1 LSB = FSR x VREF
16,384 x 4.096V
BINARY OUTPUT CODE (LSB [hex])
3FFF
3FFE
3FFD
2001
2000
1FFF
0003
0002
0001
0000
FSR
0 1 2 3 8,192 16,381 16,383
INPUT VOLTAGE (LSB [DECIMAL])
(AGND1)
FSR
Figure 14. Ideal Unipolar Transfer Function, Single-Ended
Input, 0 to +FSR
1 LSB = FSR x VREF
16,384 x 4.096V
BINARY OUTPUT CODE (LSB [hex])
3FFF
3FFE
3FFD
2001
2000
1FFF
0003
0002
0001
0000
FSR
-8,192 -8,190 0 +8,189 +8,191
INPUT VOLTAGE (LSB [DECIMAL])
AGND1 (DIF/SGL = 0)
CH_- (DIF/SGL = 1)
FSR
-1 +1
Figure 12. Ideal Bipolar Transfer Function, Single-Ended or
Differential Input
• User supplies one byte of SCLK, then drives CS
high to relieve processor load while the ADC
converts
• After SSTRB transitions high, the user supplies
two bytes of SCLK and reads data at DOUT
External Clock Mode (Mode 0)
The MAX1032/MAX1033’s fastest maximum throughput
rate is achieved operating in external clock mode.
SCLK controls both the acquisition and conversion of
the analog signal, facilitating precise control over when
the analog signal is captured. The analog input sam-
pling instant is at the falling edge of the 14th SCLK
(Figure 2).
Since SCLK drives the conversion in external clock
mode, the SCLK frequency should remain constant
while the conversion is clocked. The minimum SCLK
frequency prevents droop in the internal sampling
capacitor voltages during conversion.
SSTRB remains low in the external clock mode, and as a
result may be left unconnected if the MAX1032/
MAX1033 will always be used in the external clock mode.
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
______________________________________________________________________________________ 23
CS
SCLK
DIN
DOUT
18
START SEL2 SEL1 SEL0 R2 R1 R0
DIF/SGL
tCL
tCP
tCH
tDV
tCSS
tDS tDH
tCSH
tCSPW
tTR
18
START M2 M1 M0 1 0 0 0
ANALOG INPUT CONFIGURATION BYTE MODE CONTROL BYTE
HIGH
IMPEDANCE
HIGH
IMPEDANCE
HIGH
IMPEDANCE
Figure 15. Analog Input Configuration Byte and Mode-Control Byte Timing
CS
SCLK
DOUT
tCSS
SSTRB
tSSCS
MSB
tDO
NOTE: SSTRB AND CS REMAIN LOW IN EXTERNAL CLOCK MODE (MODE 0).
HIGH IMPEDANCE
Figure 16. DOUT and SSTRB Timing
Table 7. Mode-Control Byte
BIT NUMBER
BIT NAME DESCRIPTION
7 START Start Bit. The first logic 1 after CS goes low defines the beginning of the mode-control byte.
6M2
5M1
4M0
Mode-Control Bits. M[2:0] select the mode of operation as shown in Table 8.
3 1 Bit 3 must be a logic 1 for the mode-control byte.
2 0 Bit 2 must be a logic 0 for the mode-control byte.
1 0 Bit 1 must be a logic 0 for the mode-control byte.
0 0 Bit 0 must be a logic 0 for the mode-control byte.
External Acquisition Mode (Mode 1)
The slowest maximum throughput rate is achieved with
the external acquisition method. SCLK controls the acqui-
sition of the analog signal in external acquisition mode,
facilitating precise control over when the analog signal is
captured. The internal clock controls the conversion of
the analog input voltage. The analog input sampling
instant is at the falling edge of the 16th SCLK (Figure 3).
For the external acquisition mode, CS must remain low
for the first 15 clock cycles and then rise on or after the
falling edge of the 16th clock cycle as shown in Figure
3. For optimal performance, idle DIN and SCLK during
the conversion. With careful board layout, transitions at
DIN and SCLK during the conversion have a minimal
impact on the conversion result.
After the conversion is complete, SSTRB asserts high
and CS can be brought low to read the conversion
result. SSTRB returns low on the rising SCLK edge of
the subsequent start bit.
Internal Clock Mode (Mode 2)
In internal clock mode, the internal clock controls both
acquisition and conversion of the analog signal. The inter-
nal clock starts approximately 100ns to 400ns after the
falling edge of the eighth SCLK and has a rate of about
4.5MHz. The analog input sampling instant occurs at the
falling edge of the 11th internal clock signal (Figure 4).
For the internal clock mode, CS must remain low for the
first seven SCLK cycles and then rise on or after the
falling edge of the eighth SCLK cycle. After the conver-
sion is complete, SSTRB asserts high and CS can be
brought low to read the conversion result. SSTRB returns
low on the rising SCLK edge of the subsequent start bit.
Reset (Mode 4)
As shown in Table 8, set M[2:0] = 100 to reset the
MAX1032/MAX1033 to its default conditions. The
default conditions are full power operation with each
channel configured for ±12V, bipolar, single-ended
conversions using external clock mode (mode 0).
Partial Power-Down Mode (Mode 6)
As shown in Table 8, when M[2:0] = 110, the device
enters partial power-down mode. In partial power-
down, all analog portions of the device are powered
down except for the reference voltage generator and
bias supplies.
To exit partial power-down, change the mode by issu-
ing one of the following mode-control bytes (see the
Mode Control section):
• External-Clock-Mode Control Byte
• External-Acquisition-Mode Control Byte
• Internal-Clock-Mode Control Byte
• Reset Byte
• Full Power-Down-Mode Control Byte
This prevents the MAX1032/MAX1033 from inadvertent-
ly exiting partial power-down mode because of a CS
glitch in a noisy digital environment.
Full Power-Down Mode (Mode 7)
When M[2:0] = 111, the device enters full power-down
mode and the total supply current falls to 1µA (typ). In
full power-down, all analog portions of the device are
powered down. When using the internal reference,
upon exiting full power-down mode, allow 10ms for the
internal reference voltage to stabilize prior to initiating a
conversion.
To exit full power-down, change the mode by issuing
one of the following mode-control bytes (see the Mode
Control section):
• External-Clock-Mode Control Byte
• External-Acquisition-Mode Control Byte
• Internal-Clock-Mode Control Byte
• Reset Byte
• Partial Power-Down-Mode Control Byte
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
24 ______________________________________________________________________________________
M2 M1 M0 MODE
0 0 0 External Clock (DEFAULT)
0 0 1 External Acquisition
0 1 0 Internal Clock
0 1 1 Reserved
1 0 0 Reset
1 0 1 Reserved
1 1 0 Partial Power-Down
1 1 1 Full Power-Down
Table 8. Mode-Control Bits M[2:0]
This prevents the MAX1032/MAX1033 from inadvertent-
ly exiting full power-down mode because of a CS glitch
in a noisy digital environment.
Power-On Reset
The MAX1032/MAX1033 power up in normal operation
configured for external clock mode with all circuitry
active (Tables 7 and 8). Each analog input channel
(CH0–CH7) is set for single-ended conversions with a
±12V bipolar input range (Table 6).
Allow the power supplies to stabilize after power-up. Do
not initiate any conversions until the power supplies
have stabilized. Additionally, allow 10ms for the internal
reference to stabilize when CREF = 1.0µF and CRECAP
= 0.1µF. Larger reference capacitors require longer
stabilization times.
Internal or External Reference
The MAX1032/MAX1033 operate with either an internal or
external reference. The reference voltage impacts the
ADC’s FSR (Figures 12, 13, and 14). An external refer-
ence is recommended if more accuracy is required than
the internal reference provides, and/or multiple converters
require the same reference voltage.
Internal Reference
The MAX1032/MAX1033 contain an internal 4.096V
bandgap reference. This bandgap reference is connect-
ed to REFCAP through a nominal 5kΩresistor (Figure 17).
The voltage at REFCAP is buffered creating 4.096V at
REF. When using the internal reference, bypass
REFCAP with a 0.1µF or greater capacitor to AGND1 and
bypass REF with a 1.0µF or greater capacitor to AGND1.
External Reference
For external reference operation, disable the internal
reference and reference buffer by connecting REFCAP
to AVDD1. With AVDD1 connected to REFCAP, REF
becomes a high-impedance input and accepts an
external reference voltage. The MAX1032/MAX1033
external reference current varies depending on the
applied reference voltage and the operating mode (see
the External Reference Input Current vs. External
Reference Input Voltage in the Typical Operating
Characteristics).
Applications Information
Noise Reduction
Additional samples can be taken and averaged (over-
sampling) to remove the effect of transition noise on
conversion results. The square root of the number of
samples determines the improvement in performance.
For example, with 2/3LSBRMS (4LSBP-P) transition
noise, 16 (42= 16) samples must be taken to reduce
the noise to 1LSBP-P.
Interface with 0 to 10V Signals
In industrial-control applications, 0 to 10V signaling is
common. For 0 to 10V applications, configure the select-
ed MAX1032/MAX1033 input channel for the single-
ended 0 to 12V input range (R[2:0] = 110, Table 6). The 0
to 12V range accommodates 0 to 10V where the signals
saturate at approximately 12V if out of range.
Interface with 4–20mA Signals
Figure 19 illustrates a simple interface between the
MAX1032/MAX1033 and a 4–20mA signal. 4–20mA sig-
naling can be used as a binary switch (4mA represents
a logic-low signal, 20mA represents a logic-high sig-
nal), or for precision communication where currents
between 4mA and 20mA represent intermediate analog
data. For binary switch applications, connect the
4–20mA signal to the MAX1032/MAX1033 with a resis-
tor to ground. For example, a 250Ωresistor converts
the 4–20mA signal to a 1V to 5V signal. Adjust the
resistor value so the parallel combination of the resistor
and the MAX1032/MAX1033 source impedance is
250Ω. In this application, select the single-ended 0 to
6V range (R[2:0] = 011, Table 6). For applications that
require precision measurements of continuous analog
currents between 4mA and 20mA, use a buffer to pre-
vent the MAX1032/MAX1033 input from diverting cur-
rent from the 4–20mA signal.
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
______________________________________________________________________________________ 25
REF
REFCAP
AGND1
4.096V
BANDGAP
REFERENCE
5kΩ
1x
SAR
ADC REF
4.096V
1.0µF
0.1µF
VRCTH
MAX1032
MAX1033
Figure 17. Internal Reference Operation
Bridge Application
The MAX1032/MAX1033 convert 1kHz signals more
accurately than a similar sigma-delta converter that
might be considered in bridge applications. The input
impedance of the MAX1032, in combination with the cur-
rent-limiting resistors, can affect the gain of the
MAX1032. In many applications this error is acceptable,
but for applications that cannot tolerate this error, the
MAX1032 inputs can be buffered (Figure 20). Connect
the bridge to a low-offset differential amplifier and then
the true-differential inputs of the MAX1032/MAX1033.
Larger excitation voltages take advantage of more of the
±3V differential input voltage range. Select an input volt-
age range that matches the amplifier output. Be aware of
the amplifier offset and offset-drift errors when selecting
an appropriate amplifier.
Dynamically Adjusting the Input Range
Software control of each channel’s analog input range
and the unipolar endpoint overlap specification make it
possible for the user to change the input range for a
channel dynamically and improve performance in some
applications. Changing the input range results in a
small LSB step-size over a wider output voltage range.
For example, by switching between a -6V to 0V range
and a 0 to 6V range, an LSB is
but the input voltage range effectively spans from -6V
to +6V (FSR = 12V).
Layout, Grounding, and Bypassing
Careful PC board layout is essential for best system per-
formance. Boards should have separate analog and digi-
tal ground planes and ensure that digital and analog
signals are separated from each other. Do not run analog
and digital (especially clock) lines parallel to one another,
or digital lines underneath the device package.
Figure 1 shows the recommended system ground con-
nections. Establish an analog ground point at AGND1
and a digital ground point at DGND. Connect all analog
grounds to the star analog ground. Connect the digital
grounds to the star digital ground. Connect the digital
ground plane to the analog ground plane at one point.
For lowest noise operation, make the ground return to
the star ground’s power-supply low impedance and as
short as possible.
High-frequency noise in the AVDD1 power supply
degrades the ADC’s high-speed comparator perfor-
mance. Bypass AVDD1 to AGND1 with a 0.1µF ceramic
surface-mount capacitor. Make bypass capacitor con-
nections as short as possible.
Parameter Definitions
Integral Nonlinearity (INL)
INL is the deviation of the values on an actual transfer
function from a straight line. This straight line is either a
best straight-line fit or a line drawn between the end-
points of the transfer function once offset and gain
errors have been nullified. The MAX1032/MAX1033 INL
is measured using the endpoint method.
6
16 384 4 096
VV
REF
, .
×
×
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
26 ______________________________________________________________________________________
REF
REFCAP
AGND1
4.096V
BANDGAP
REFERENCE
5kΩ
1x
SAR
ADC REF
4.096V
1.0µF
VRCTH
MAX1032
MAX1033
AVDD1
MAX6341
V+
1.0µF
OUT
GND
IN
Figure 18. External Reference Operation
Differential Nonlinearity (DNL)
DNL is the difference between an actual step width and
the ideal value of 1 LSB. A DNL error specification of
greater than -1 LSB guarantees no missing codes and
a monotonic transfer function.
Transition Noise
Transition noise is the amount of noise that appears at a
code transition on the ADC transfer function. Conversions
performed with the analog input right at the code transi-
tion can result in code flickering in the LSBs.
Channel-to-Channel Isolation
Channel-to-channel isolation indicates how well each
analog input is isolated from the others. The channel-to-
channel isolation for these devices is measured by
applying a near full-scale magnitude 5kHz sine wave to
the selected analog input channel while applying an
equal magnitude sine wave of a different frequency to
all unselected channels. An FFT of the selected chan-
nel output is used to determine the ratio of the magni-
tudes of the signal applied to the unselected channels
and the 5kHz signal applied to the selected analog
input channel. This ratio is reported, in dB, as channel-
to-channel isolation.
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
______________________________________________________________________________________ 27
MAX1032
250Ω
4–20mA INPUT
250Ω
4–20mA INPUT
CH0
CH8
µC
Figure 19. 4–20mA Application
MAX1032
MAX1033
CH0
REF
µP
CH1
LOW-OFFSET
DIFFERENTIAL
AMPLIFIER
BRIDGE
Figure 20. Bridge Application
Unipolar Offset Error
-FSR to 0V
When a zero-scale analog input voltage is applied to
the converter inputs, the digital output is all ones
(0x3FFF). Ideally, the transition from 0x3FFF to 0x3FFE
occurs at AGND1 - 0.5 LSB. Unipolar offset error is the
amount of deviation between the measured zero-scale
transition point and the ideal zero-scale transition point,
with all untested channels grounded.
0V to +FSR
When a zero-scale analog input voltage is applied to
the converter inputs, the digital output is all zeros
(0x0000). Ideally, the transition from 0x0000 to 0x0001
occurs at AGND1 + 0.5 LSB. Unipolar offset error is the
amount of deviation between the measured zero-scale
transition point and the ideal zero-scale transition point,
with all untested channels grounded.
Bipolar Offset Error
When a zero-scale analog input voltage is applied to
the converter inputs, the digital output is a one followed
by all zeros (0x2000). Ideally, the transition from
0x1FFF to 0x2000 occurs at (2N-1 - 0.5)LSB. Bipolar off-
set error is the amount of deviation between the mea-
sured midscale transition point and the ideal midscale
transition point, with untested channels grounded.
Gain Error
When a positive full-scale voltage is applied to the con-
verter inputs, the digital output is all ones (0x3FFF). The
transition from 0x3FFE to 0x3FFF occurs at 1.5 LSB
below full scale. Gain error is the amount of deviation
between the measured full-scale transition point and
the ideal full-scale transition point with the offset error
removed and all untested channels grounded.
Unipolar Endpoint Overlap
Unipolar endpoint overlap is the change in offset when
switching between complementary input voltage
ranges. For example, the difference between the volt-
age that results in a 0x3FFF output in the -6V to 0V
input voltage range and the voltage that results in a
0x0000 output in the 0 to +6V input voltage range is the
unipolar endpoint overlap. The unipolar endpoint over-
lap is positive for the MAX1032/MAX1033, preventing
loss of signal or a dead zone when switching between
adjacent analog input voltage ranges.
Small-Signal Bandwidth
A 100mVP-P sine wave is applied to the ADC, and the
input frequency is then swept up to the point where the
amplitude of the digitized conversion result has
decreased by -3dB.
Full-Power Bandwidth
A 95% of full-scale sine wave is applied to the ADC,
and the input frequency is then swept up to the point
where the amplitude of the digitized conversion result
has decreased by -3dB.
Common-Mode Rejection Ratio (CMRR)
CMRR is the ability of a device to reject a signal that is
“common” to or applied to both input terminals. The
common-mode signal can be either an AC or a DC sig-
nal or a combination of the two. CMR is expressed in
decibels. Common-mode rejection ratio is the ratio of
the differential signal gain to the common-mode signal
gain. CMRR applies only to differential operation.
Power-Supply Rejection Ratio (PSRR)
PSRR is the ratio of the output-voltage shift to the
power-supply-voltage shift for a fixed input voltage. For
the MAX1032/MAX1033, AVDD1 can vary from 4.75V to
5.25V. PSRR is expressed in decibels and is calculated
using the following equation:
For the MAX1032/MAX1033, PSRR is tested in bipolar
operation with the analog inputs grounded.
Aperture Jitter
Aperture jitter, tAJ, is the statistical distribution of the
variation in the sampling instant (Figure 21).
Aperture Delay
Aperture delay, tAD, is the time from the falling edge of
SCLK to the sampling instant (Figure 21).
Signal-to-Noise Ratio (SNR)
SNR is computed by taking the ratio of the RMS signal
to the RMS noise. RMS noise includes all spectral com-
ponents to the Nyquist frequency excluding the funda-
mental, the first five harmonics, and the DC offset.
Signal-to-Noise Plus Distortion (SINAD)
SINAD is computed by taking the ratio of the RMS sig-
nal to the RMS noise plus distortion. RMS noise plus
distortion includes all spectral components to the
Nyquist frequency excluding the fundamental and the
DC offset.
SINAD dB Signal
Noise
RMS
RMS
( ) log=×
⎛
⎝
⎜⎞
⎠
⎟
20
PSRR dB VV
VVVV
OUT OUT
[ ] log . .
(. ) (. )
=×
⎛
⎝
⎜⎞
⎠
⎟
−
−
20 525 475
525 475
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
28 ______________________________________________________________________________________
Effective Number of Bits (ENOB)
ENOB indicates the global accuracy of an ADC at a
specific input frequency and sampling rate. With an
input range equal to the ADC’s full-scale range, calcu-
late the ENOB as follows:
Total Harmonic Distortion (THD)
For the MAX1032/MAX1033, THD is the ratio of the
RMS sum of the input signal’s first four harmonic com-
ponents to the fundamental itself. This is expressed as:
where V1is the fundamental amplitude, and V2through
V5are the amplitudes of the 2nd- through 5th-order
harmonic components.
Spurious-Free Dynamic Range (SFDR)
SFDR is the ratio of RMS amplitude of the fundamental
(maximum signal component) to the RMS value of the
next-largest spectral component.
THD VVVV
V
log
=× +++
⎛
⎝
⎜
⎜
⎞
⎠
⎟
⎟
20 22324252
1
ENOB SINAD
.
.
=⎛
⎝
⎜⎞
⎠
⎟
−176
602
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
______________________________________________________________________________________ 29
tAD
tAJ
INTCLK
(MODE 2)
ANALOG INPUT
TRACK AND HOLD TRACK HOLD
SAMPLE INSTANT
SCLK
(MODE 0) 13 14 15
SCLK
(MODE 1) 15 16
10 11 12
Figure 21. Aperture Diagram
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
30 ______________________________________________________________________________________
Chip Information
TRANSISTOR COUNT: 28,210
PROCESS: BiCMOS
Block Diagram
MAX1032
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7
AGND1
ANALOG
INPUT MUX
AND
MULTIRANGE
CIRCUITRY
PGA
AGND2
AVDD2
4.096V
BANDGAP
REFERENCE
1x
5kΩ
IN
REF
REFCAP
REF
CONTROL LOGIC AND REGISTERS
FIFO
CLOCK
OUT
SAR
ADC
SERIAL I/O
AGND2
AVDD2
AGND3
AVDD1
DGND
DVDD
DGNDO
SCLK
DOUT
SSTRB
DIN
CS
DVDDO
Pin Configurations (continued)
20
19
18
17
16
15
14
13
1
2
3
4
5
6
7
8
AGND2
AVDD2
AGND3
REFCH1
CH0
AVDD1
AGND1
REFCAP
DVDD
DVDDO
DGNDDIN
CS
CH3
CH2
12
11
9
10
DGNDO
DOUTSCLK
SSTRB
MAX1033
TSSOP
TOP VIEW +
MAX1032/MAX1033
8-/4-Channel, ±12V Multirange Inputs,
Serial 14-Bit ADCs
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implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
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Revision History
Pages changed at Rev 2: 1, 3–6, 30, 31
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
TSSOP4.40mm.EPS
PACKAGE OUTLINE, TSSOP 4.40mm BODY
21-0066
1
1
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