General Description
The MAX9672/MAX9673/MAX9674 output 12/14/16 volt-
age references for gamma correction in TFT LCDs and
one voltage reference for VCOM. Each gamma refer-
ence voltage has its own 10-bit DAC and buffer to
ensure a stable voltage. The VCOM reference voltage
has its own 10-bit DAC and an amplifier to ensure a sta-
ble voltage when critical levels and patterns are dis-
played. The MAX9672/MAX9673/MAX9674 feature
integrated multiple-time programmable (MTP) memory to
store gamma and VCOM values on the chip, eliminating
the need for external EEPROM. The MAX9672/
MAX9673/MAX9674 support up to 300 write operations
to the on-chip nonvolatile memory.
The gamma outputs can drive 200mA peak transient
current and settle within 1µs. The VCOM output can
provide 600mA peak transient current and also settles
within 1µs. The analog supply voltage range extends
from 9V to 20V, and the digital supply voltage range
extends from 2.7V to 3.6V.
Gamma values and the VCOM value are programmed
into registers through the I2C interface.
Applications
TFT LCDs
Features
oDAC Reference Input
o12/14/16-Channel Gamma Correction, 10-Bit
Resolution
oVCOM Driver
oIntegrated MTP Memory
oProgrammable VCOM Limits
o200mA Peak Current on Gamma Channels
o600mA Peak Current on VCOM Channel
MAX9672/MAX9673/MAX9674
10-Bit, Programmable Gamma Reference
Systems with MTP for TFT LCDs
________________________________________________________________
Maxim Integrated Products
1
19-4718; Rev 4; 2/11
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.
EVALUATION KIT
AVAILABLE
Ordering Information
PART GAMMA
CHANNELS PIN-PACKAGE
MAX9672ETI+ 12 28 TQFN-EP*
MAX9673ETI+ 14 28 TQFN-EP*
MAX9674ETI+ 16 28 TQFN-EP*
+
Denotes a lead(Pb)-free/RoHS-compliant package.
*
EP = Exposed pad.
Note: All devices are specified over the -40°C to +85°C temper-
ature range.
DAC
REGISTERS
I2C
REGISTERS
I2C
INTERFACE
MTP
MEMORY
10-BIT
DAC
10 GMA1
REF
10
10-BIT
DAC
10 GMA2
10
10-BIT
DAC
10 GMA3
10
10-BIT
DAC
10 GMA4
10
10-BIT
DAC
10 GMA5
10
10-BIT
DAC
10 GMA6
10
10-BIT
DAC
10 GMA7
10
10-BIT
DAC
10 GMA8
10
10-BIT
DAC
10 GMA9
10
10-BIT
DAC
10 GMA10
10
10-BIT
DAC
10 GMA11
10
10-BIT
DAC
10 GMA12
10
10-BIT
DAC
10 GMA13*
10
10-BIT
DAC
10 GMA14*
10
10-BIT
DAC
10 GMA15**
10
10-BIT
DAC
10 GMA16**
DVDD
SDA
SCL
A0
GND
10
10-BIT
DAC
10 AVDD_AMP
AGND_AMP
VCOM_FB
VCOM
10
GND
MAX9672
MAX9673
MAX9674
AVDD
*NOT AVAILABLE FOR THE MAX9672
**NOT AVAILABLE FOR THE MAX9672 AND THE MAX9673
Functional Diagram
THIN QFN
(5mm × 5mm)
TOP VIEW
26
27
25
24
10
9
11
SCL
A0
DVDD
AGND_AMP
VCOM
12
GMA16**
REF
GMA7
GMA6
AVDD
GMA5
GMA4
12
GMA12
4567
2021 19 17 16 15
GMA13*
GMA14*
GMA1
GND
AVDD
AVDD_AMP
SDA GMA8
3
18
28 8
GMA15** VCOM_FB
GMA11
23 13 GMA2
GMA10
22 14 GMA3
GMA9
+EP†
†EP = EXPOSED PAD, CONNECT EP TO GROUND PLANE.
*N.C. FOR THE MAX9672
**N.C. FOR THE MAX9672 AND THE MAX9673
MAX9672
MAX9673
MAX9674
Pin Configuration
MAX9672/MAX9673/MAX9674
10-Bit, Programmable Gamma Reference
Systems with MTP for TFT LCDs
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VAVDD = 18V, VAVDD_AMP = VREF = 18V, VDVDD = 3.3V, VGND = VAGND_AMP = 0, VCOM = VCOM_FB, no load, TA= TMIN to TMAX,
unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
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.
Supply Voltages
AVDD, REF to GND ............................................-0.3V to +22V
AVDD_AMP to AGND_AMP................................-0.3V to +22V
AVDD to AVDD_AMP.........................................-0.3V to +0.3V
DVDD to GND.......................................................-0.3V to +4V
AGND_AMP to GND..........................................-0.1V to +0.1V
Outputs
GMA1–GMA16 ...................................-0.3V to (VAVDD + 0.3V)
VCOM.........................................-0.3V to (VAVDD_AMP + 0.3V)
Inputs
SDA, SCL..............................................................-0.3V to +6V
VCOM_FB...................................-0.3V to (VAVDD_AMP + 0.3V)
SDA, SCL..........................................................................±20mA
GMA1–GMA16................................................................±200mA
VCOM .............................................................................±600mA
Continuous Power Dissipation (TA= +70°C)
28-Pin TQFN-EP (derate 28.6mW/°C
above +70°C) ........................................................2285.7mW
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
Soldering Temperature (reflow) ...................................... +260°C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
SUPPLIES
Analog Supply Voltage Range VAVDD,
VAVDD_AMP Guaranteed by total output error 9 20 V
Analog Supply Voltage Range for
Programming MTP VAVDD_MTP 15 20 V
Digital Supply Voltage Range VDVDD 2.7 3.6 V
Analog Quiescent Current IAVDD 20 35 mA
VCOM Quiescent Current IAVDD_AMP 2.7 5.6 mA
During a register mode load event 400
Digital Quiescent Current IDVDD No SCL or SDA transitions 260 600 µA
Thermal Shutdown +160 °C
Thermal-Shutdown Hysteresis 15 °C
Undervoltage Lockout Threshold UVLO DVDD undervoltage lockout voltage
threshold 2.3 2.6 V
REF Input Resistance 384 kΩ
VCOM OUTPUT (VCOM)
Resolution RES 10 Bits
Integral Nonlinearity Error INL 0.125 1 LSB
Differential Nonlinearity Error DNL 0.125 1 LSB
Total Output Error VERR Code = 512, VAVDD_AMP = 9V and 20V, TA
= +25°C -40 +40 mV
Total Output-Error Drift ∆VERR Code = 512 15 µV/°C
Output-Voltage Low VOUT TA = +25°C, sinking 100mA 0.4 0.85 V
MAX9672/MAX9673/MAX9674
10-Bit, Programmable Gamma Reference
Systems with MTP for TFT LCDs
_______________________________________________________________________________________ 3
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Output-Voltage High VOUT TA = +25°C, sourcing 100mA VAVDD_AMP
- 1.1
VAVDD_AMP
- 0.6 V
To AVDD_AMP, f = 60kHz, REF shorted to
VAVDD_AMP 40
Power-Supply Rejection Ratio PSRR
9V ≤ VAVDD_AMP ≤ 20V 60 90
dB
Output Load Regulation LR Transient -80mA to +80mA, code = 512 ±0.1 mV/mA
Continuous Output Current IOCode = 512 (Note 2) 80 mA
Short-Circuit Current 9V ≤ VAVDD_AMP ≤ 20V 600 mA
Slew Rate SR Swing 4VP-P at VCOM, 10% to 90%,
RL = 10kΩ, CL = 50pF (Note 3) 100 V/µs
Program to Output Delay tD
From SCL rising edge for ACK bit after
programming VCOM to 50% voltage
change at output
0.8 µs
Bandwidth BW RS = 10kΩ, CL = 50pF (Note 3) 60 MHz
Noise eNRMS noise voltage (10MHz BW) 375 µV
DAC OUTPUTS (GMA1–GMA16)
Resolution RES Guaranteed monotonic 10 Bits
Integral Nonlinearity Error INL 0.125 1 LSB
Differential Nonlinearity Error DNL 0.125 1 LSB
Total Output Error VERR Code = 512, VAVDD = 9V and 20V,
TA = +25°C -40 +40 mV
Output-Voltage Low VOUT TA = +25°C, sinking 10mA 0.15 0.28 V
Output-Voltage High VOUT TA = +25°C, sourcing 10mA VAVDD
- 0.38
VAVDD
- 0.25 V
To AVDD, f = 60kHz, REF shorted to
AVDD 40
Power-Supply Rejection Ratio PSRR
9V ≤ VAVDD ≤ 20V 60 90
dB
Load Regulation LR -12mA to +12mA 0.5 mV/mA
Short-Circuit Current ISC Outputs to AVDD or GND 200 mA
Output Impedance ZOOutput resistance when output is disabled 84 kΩ
Slew Rate SR Swing 5VP-P at input, 10% to 90%
measurement on output 22 V/µs
Program to Output Delay tD
From SCL rising edge for ACK bit after
programming gamma to 50% voltage
change at output
0.8 µs
Noise eNRMS noise voltage at any output (10MHz
BW) 375 µV
Channel-to-Channel Isolation CXTLK f = 5MHz, all channels to all channels 80 dB
ELECTRICAL CHARACTERISTICS (continued)
(VAVDD = 18V, VAVDD_AMP = VREF = 18V, VDVDD = 3.3V, VGND = VAGND_AMP = 0, VCOM = VCOM_FB, no load, TA= TMIN to TMAX,
unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
MAX9672/MAX9673/MAX9674
10-Bit, Programmable Gamma Reference
Systems with MTP for TFT LCDs
4 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(VAVDD = 18V, VAVDD_AMP = VREF = 18V, VDVDD = 3.3V, VGND = VAGND_AMP = 0, VCOM = VCOM_FB, no load, TA= TMIN to TMAX,
unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
LOGIC INPUTS (SDA, SCL)
Input High Voltage VIH 0.7 x
VDVDD V
Input Low Voltage VIL 0.3 x
VDVDD V
Input Leakage Current IIH, IIL VIN = 0V or VDVDD -1 +0.01 +1 µA
Input Capacitance 5pF
Power-Down Input Current IIN VDVDD = 0V, VIN = 2V -10 +10 µA
SDA Output Low Voltage VOL ISINK = 6mA 0.4 V
I2C TIMING CHARACTERISTICS (Figure 1)
Serial-Clock Frequency fSCL 0 400 kHz
Bus Free Time Between STOP
and START Conditions tBUF 1.3 µs
Hold Time (REPEATED) START
Condition tHD,STA 0.6 µs
SCL Pulse-Width Low tLOW 1.3 µs
SCL Pulse-Width High tHIGH 0.6 µs
Setup Time for a REPEATED
START Condition tSU,STA 0.6 µs
Data Hold Time tHD,DAT 0 900 ns
Data Setup Time tSU,DAT 100 ns
SDA and SCL Receiving Rise
Time tR(Note 4) 20 +
0.1CB300 ns
SDA and SCL Receiving Fall
Time tF(Note 4) 20 +
0.1CB300 ns
SDA Transmitting Fall
Time tF,TX (Note 4) 20 +
0.1CB250 ns
Setup Time for STOP Condition tSU,STO 0.6 µs
Bus Capacitance CB400 pF
Pulse Width of Suppressed Spike tSP 050ns
Note 1: All devices are 100% production tested at TA= +25°C. All temperature limits are guaranteed by design.
Note 2: Thermal pad attached to multilayered board. Exceeding this limit may cause the thermal shutdown to trip.
Note 3: Measured with the VCOM amplifier configured as an inverting unity-gain amplifier (RS= RF= 1kΩ).
Note 4: CBis in pF.
MAX9672/MAX9673/MAX9674
10-Bit, Programmable Gamma Reference
Systems with MTP for TFT LCDs
_______________________________________________________________________________________ 5
0
5
10
15
20
25
30
OUTPUT OFFSET-VOLTAGE
DISTRIBUTION
MAX9672/73/74 toc01
OUTPUT OFFSET (mV)
N (%)
-40 -30 -20 -10 010 20 30 40
-20
-10
-15
0
-5
5
10
15
20
-20 -10 -5-15 0 5 101520
GAMMA LOAD REGULATION
MAX9672/73/74 toc02
LOAD CURRENT (mA)
LOAD REGULATION (mV)
-60
-20
-40
20
0
40
60
-150 -50 0-100 50 100 150
VCOM LOAD REGULATION
MAX9672/73/74 toc03
LOAD CURRENT (mA)
LOAD REGULATION (mV)
-0.25
-0.15
-0.20
-0.05
-0.10
0.05
0
0.10
0.20
0.15
0.25
0 256 384128 512 640 768 896 1024
DNL
GAMMA
MAX9672/73/74 toc04
CODE (UNITS)
DNL (LSB)
-0.25
-0.15
-0.20
-0.05
-0.10
0.05
0
0.10
0.20
0.15
0.25
0 256 384128 512 640 768 896 1024
DNL
VCOM
MAX9672/73/74 toc05
CODE
(
UNITS
)
DNL (LSB)
Typical Operating Characteristics
(VAVDD = VAVDD_AMP = VREF = 18V, VDVDD = 3.3V, VGND = VAGND_AMP = 0, no load, unless otherwise noted. Typical values are at
TA= +25°C.)
GAMMA
INL
MAX9672 toc06
INL (LSB)
-0.20
-0.15
-0.10
-0.05
0
0.05
0.10
0.15
0.20
0.25
-0.25
CODE (UNITS)
896768128 256 384 512 6400 1024
VREF = 10V
MAX9672/MAX9673/MAX9674
10-Bit, Programmable Gamma Reference
Systems with MTP for TFT LCDs
6 _______________________________________________________________________________________
Typical Operating Characteristics (continued)
(VAVDD = VAVDD_AMP = VREF = 18V, VDVDD = 3.3V, VGND = VAGND_AMP = 0, no load, unless otherwise noted. Typical values are at
TA= +25°C.)
-0.25
-0.15
-0.20
-0.05
-0.10
0.05
0
0.10
0.20
0.15
0.25
0 256 384128 512 640 768 896 1024
VCOM
INL
MAX9672/73/74 toc09
CODE (UNITS)
INL (LSB)
-0.25
-0.15
-0.20
-0.05
-0.10
0.05
0
0.10
0.20
0.15
0.25
0 256 384128 512 640 768 896 1024
GAMMA
INL
MAX9672/73/74 toc08
CODE (UNITS)
INL (LSB)
GAMMA
DNL
CODE (UNITS)
DNL (LSB)
-0.08
-0.04
0
0.04
0.08
0.12
-0.12
MAX9672
toc
10
896768128 256 384 512 64001024
VCOM
DNL
MAX9672 toc11
CODE (UNITS)
DNL (LSB)
896768128 256 384 512 640
-0.15
-0.10
-0.05
0
0.05
0.10
0.15
0.20
-0.20
0 1024
VREF = 10V
VCOM
INL
MAX9672 toc07
CODE (UNITS)
INL (LSB)
896768128 256 384 512 640
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
-0.4
01024
VREF = 10V
MAX9672/MAX9673/MAX9674
10-Bit, Programmable Gamma Reference
Systems with MTP for TFT LCDs
_______________________________________________________________________________________
7
VOUT
250mV/div
IOUT
250mA/div
VCOM PULSE RESPONSE
MAX9672/73/74 toc16
TIME (2µs/div)
RISO = 10Ω
CLOAD = 68nF
-2.5V TO +2.5V
CLOAD
RISO VCOM
DAC
VOUT
1V/div
IOUT
50mA/div
GAMMA PULSE RESPONSE
MAX9672/73/74 toc17
TIME (2µs/div)
RISO = 10Ω
CLOAD = 10nF
-2.5V TO +2.5V
CLOAD
RISO GAMMA
DAC
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY, GAMMA OUTPUTS
MAX9672 toc12
FREQUENCY (Hz)
PSRR (dB)
1M100k
-70
-60
-50
-40
-30
-20
-10
0
-80
10k 10M
VRIPPLE = 200mVP-P
CODE = 512
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY, VCOM OUTPUT
MAX9672 toc13
FREQUENCY (Hz)
PSRR (dB)
1M100k
-70
-60
-50
-40
-30
-20
-10
0
-80
10k 10M
VRIPPLE = 200mVP-P
CODE = 512
REFERENCE REJECTION RATIO
vs. FREQUENCY, GAMMA OUTPUTS
MAX9672 toc14
FREQUENCY (Hz)
REFERENCE REJECTION RATIO (dB)
1M100k
-70
-60
-50
-40
-30
-20
-10
0
-80
10k 10M
VRIPPLE = 200mVP-P
CODE = 512
REFERENCE REJECTION RATIO
vs. FREQUENCY, VCOM OUTPUT
MAX9672 toc15
FREQUENCY (Hz)
REFERENCE REJECTION RATIO (dB)
1M100k
-70
-60
-50
-40
-30
-20
-10
0
-80
10k 10M
VRIPPLE = 200mVP-P
CODE = 512
Typical Operating Characteristics (continued)
(VAVDD = VAVDD_AMP = VREF = 18V, VDVDD = 3.3V, VGND = VAGND_AMP = 0, no load, unless otherwise noted. Typical values are at
TA= +25°C.)
MAX9672/MAX9673/MAX9674
10-Bit, Programmable Gamma Reference
Systems with MTP for TFT LCDs
8 _______________________________________________________________________________________
Detailed Description
The MAX9672/MAX9673/MAX9674 feature 13/15/17
total programmable reference voltage channels. Each
channel has a 10-bit DAC to create the reference volt-
age. One channel has an amplifier that follows the DAC
while all other channels have a buffer after the DAC.
The MAX9672/MAX9673/MAX9674 feature integrated
MTP memory to store gamma and VCOM values on the
chip, eliminating the need for external EEPROM. The
MAX9672/MAX9673/MAX9674 support up to 300 write
operations to the on-chip nonvolatile memory.
The MAX9672/MAX9673/MAX9674 can provide the
gamma, VCOM, and possibly level-shifter reference
voltages for an LCD panel that can potentially replace a
discrete digital variable resistor (DVR), VCOM amplifier,
Pin Description
PIN
MAX9672 MAX9673 MAX9674 NAME FUNCTION
1, 26, 27, 28 1, 28 — N.C. No Connection. Not internally connected.
— — 1 GMA16 Gamma DAC Analog Output 16
2 2 2 SCL I2C-Compatible Serial-Clock Input
3 3 3 SDA I2C-Compatible Serial-Data Input/Output
44 4A0I
2C-Compatible Device Address Bit 0
5 5 5 DVDD Digital Power Supply. Bypass DVDD with a 0.1µF capacitor to GND.
6 6 6 AGND_AMP Ground for VCOM Amplifier
7 7 7 VCOM VCOM Output
8 8 8 VCOM_FB Feedback for VCOM Amplifier
9 9 9 AVDD_AMP Power Supply for VCOM Amplifier. Bypass AVDD_AMP with a 0.1µF
capacitor to AGND_AMP.
10, 21 10, 21 10, 21 AVDD Anal og P ow er S up p l y. Byp ass AV D D w i th a 0.1µF cap aci tor to G N D .
11 11 11 GND Analog Ground
12 12 12 GMA1 Gamma DAC Analog Output 1
13 13 13 GMA2 Gamma DAC Analog Output 2
14 14 14 GMA3 Gamma DAC Analog Output 3
15 15 15 GMA4 Gamma DAC Analog Output 4
16 16 16 GMA5 Gamma DAC Analog Output 5
17 17 17 GMA6 Gamma DAC Analog Output 6
18 18 18 GMA7 Gamma DAC Analog Output 7
19 19 19 GMA8 Gamma DAC Analog Output 8
20 20 20 REF DAC Reference Input
22 22 22 GMA9 Gamma DAC Analog Output 9
23 23 23 GMA10 Gamma DAC Analog Output 10
24 24 24 GMA11 Gamma DAC Analog Output 11
25 25 25 GMA12 Gamma DAC Analog Output 12
— 26 26 GMA13 Gamma DAC Analog Output 13
— 27 27 GMA14 Gamma DAC Analog Output 14
— — 28 GMA15 Gamma DAC Analog Output 15
—— —EP
Exposed Pad. EP is internally connected to the analog ground and
digital ground. EP must be connected to the system’s ground.
MAX9672/MAX9673/MAX9674
10-Bit, Programmable Gamma Reference
Systems with MTP for TFT LCDs
_______________________________________________________________________________________ 9
gamma buffers, high-voltage linear regulator, and resis-
tor strings. The high-voltage linear regulator can be
eliminated because the DAC contains a lowpass filter
that reduces horizontal line frequency noise by 50dB.
Power sequencing is well controlled since a single chip
generates all the various reference voltages needed for
the LCD panel.
Each part has an I2C interface for programming both
the MTP memory and the I2C registers.
With the MTP memory and the I2C interface, the
MAX9672/MAX9673/MAX9674 enable automatic
gamma and automatic flicker calibration on a panel-by-
panel basis on the production line. Contact your Maxim
representative for more details.
10-Bit DACs
The voltage at REF sets the full-scale output of the
DACs. Determine the output voltage using the following
equation:
VOUT = (VREF x CODE)/2N
where CODE is the numeric value of the DAC’s binary
input code and N is the bits of resolution. For the
MAX9672/MAX9673/MAX9674, N = 10 and CODE
ranges from 0 to 1023.
The DAC can never output REF because the maximum
value of CODE is always 1 least significant bit (LSB)
less than the reference. For example, if VREF = 16V and
CODE = 1023, then the output voltage is:
VOUT = (16V x 1023)/210
= 15.98438V
Gamma Buffers
The gamma buffers are guaranteed to source or sink
10mA of DC current within 200mV of the supplies.
The source drivers can kick back a great deal of cur-
rent to the buffer outputs during a horizontal line
change or a polarity switch. The DAC output buffers
can source/sink 200mA of peak current to reduce the
recovery time of the output voltages when critical levels
and patterns are displayed.
VCOM Amplifier
The operational amplifier attached to the VCOM DAC
holds the VCOM voltage stable while providing the abil-
ity to source and sink 600mA into the backplane of a
TFT LCD panel. The operational amplifier can directly
drive the capacitive load of the TFT LCD backplane
without the need for a series resistor in most cases. The
VCOM amplifier has current limiting on its output to pro-
tect its bond wires.
If the application requires more than 600mA, buffer the
output of the VCOM amplifier with a MAX9650, a VCOM
power amplifier. The MAX9650 can source or sink 1A of
current.
Thermal Shutdown
The MAX9672/MAX9673/MAX9674 feature thermal-
shutdown protection with temperature hysteresis. When
the die temperature reaches +165°C, all of the gamma
outputs are disabled. When the die cools down by
15°C, the outputs are enabled again.
I
2
C Serial Interface
The MAX9672/MAX9673/MAX9674 feature an I2C/
SMBus™-compatible, 2-wire serial interface consisting of
a serial-data line (SDA) and a serial-clock line (SCL).
SDA and SCL facilitate communication between the
MAX9672/MAX9673/MAX9674 and the master at clock
rates up to 400kHz. Figure 1 shows the 2-wire interface
timing diagram. The master generates SCL and initiates
data transfer on the bus. A master device writes data to
the MAX9672/MAX9673/MAX9674 by transmitting the
SMBus is a trademark of Intel Corp.
SCL
SDA
START
CONDITION
STOP
CONDITION
REPEATED
START CONDITION
START
CONDITION
tHD,STA
tSU,STA tHD,STA tSP
tBUF
tSU,STO
tLOW
tSU,DAT
tHD,DAT
tHIGH
tRtF
Figure 1. I
2
C Serial-Interface Timing Diagram
MAX9672/MAX9673/MAX9674
10-Bit, Programmable Gamma Reference
Systems with MTP for TFT LCDs
10 ______________________________________________________________________________________
proper slave address followed by the register address
and then the data word. Each transmit sequence is
framed by a START (S) or REPEATED START (Sr) condi-
tion and a STOP (P) condition. Each byte is serially trans-
mitted to the MAX9672/MAX9673/MAX9674 as 8 bits and
is followed by an acknowledge clock pulse. A master
reading data from the MAX9672/MAX9673/MAX9674
transmit the proper slave address followed by a series of
nine SCL pulses. The MAX9672/MAX9673/MAX9674
transmit data on SDA in sync with the master-generated
SCL pulses. The master acknowledges receipt of each
byte of data. Each read sequence is framed by a START
or REPEATED START condition, a not acknowledge, and
a STOP condition. SDA operates as both an input and an
open-drain output. A pullup resistor, typically greater
than 500Ω, is required on the SDA bus. SCL operates as
only an input. A pullup resistor, typically greater than
500Ω, is required on SCL if there are multiple masters on
the bus, or if the master in a single-master system has an
open-drain SCL output. Series resistors in line with SDA
and SCL are optional. Series resistors protect the digital
inputs of the MAX9672/MAX9673/MAX9674 from high-
voltage spikes on the bus lines, and minimize crosstalk
and undershoot of the bus signals.
Bit Transfer
One data bit is transferred during each SCL cycle. The
data on SDA must remain stable during the high period
of the SCL pulse. Changes in SDA while SCL is high
are control signals (see the
START and STOP
Conditions
section). SDA and SCL idle high when the
I2C bus is not busy.
START and STOP Conditions
SDA and SCL idle high when the bus is not in use. A
master initiates communication by issuing a START con-
dition. A START condition is a high-to-low transition on
SDA with SCL high. A STOP condition is a low-to-high
transition on SDA while SCL is high (Figure 2). A START
condition from the master signals the beginning of a
transmission to the MAX9672/MAX9673/MAX9674. The
master terminates transmission, and frees the bus, by
issuing a STOP condition. The bus remains active if a
REPEATED START condition is generated instead of a
STOP condition.
Early STOP Conditions
The MAX9672/MAX9673/MAX9674 use a STOP condi-
tion at any point during data transmission except if the
STOP condition occurs in the same high pulse as a
START condition. For proper operation, do not send a
STOP condition during the same SCL high pulse as the
START condition.
Slave Address
The slave address is defined as the 7 most significant
bits (MSBs) followed by the read/write (R/W) bit. Set the
R/Wbit to 1 to configure the MAX9672/MAX9673/
MAX9674 to read mode. Set the R/Wbit to 0 to config-
ure the MAX9672/MAX9673/MAX9674 to write mode.
The address is the first byte of information sent to the
MAX9672/MAX9673/MAX9674 after the START condi-
tion. The MAX9672/MAX9673/MAX9674 slave address
is configured with A0. Table 1 shows the possible
addresses for the MAX9672/MAX9673/MAX9674.
Acknowledge
The acknowledge bit (ACK) is a clocked 9th bit that the
MAX9672/MAX9673/MAX9674 use to handshake
receipt of each byte of data when in write mode (see
Figure 3). The MAX9672/MAX9673/MAX9674 pull down
SDA during the entire master-generated ninth clock
pulse if the previous byte is successfully received.
Monitoring ACK allows for detection of unsuccessful
data transfers. An unsuccessful data transfer occurs if
SCL
SDA
SSrP
Figure 2. START, STOP, and REPEATED START Conditions
A0 READ ADDRESS WRITE ADDRESS
GND E9h E8h
DVDD EBh EAh
Table 1. Slave Address
1
SCL
START
CONDITION
SDA
289
CLOCK PULSE FOR
ACKNOWLEDGMENT
ACKNOWLEDGE
NOT ACKNOWLEDGE
Figure 3. Acknowledge
MAX9672/MAX9673/MAX9674
10-Bit, Programmable Gamma Reference
Systems with MTP for TFT LCDs
______________________________________________________________________________________ 11
a receiving device is busy or if a system fault has
occurred. In the event of an unsuccessful data transfer,
the bus master may retry communication. The master
pulls down SDA during the ninth clock cycle to
acknowledge receipt of data when the MAX9672/
MAX9673/MAX9674 are in read mode. An acknowledge
is sent by the master after each read byte to allow data
transfer to continue. A not acknowledge is sent when
the master reads the final byte of data from the
MAX9672/MAX9673/MAX9674, followed by a STOP
condition.
Write Data Format
A write to the MAX9672/MAX9673/MAX9674 consists of
transmitting a START condition, the slave address with
the R/Wbit set to 0, one data byte of data to configure
the internal register address pointer, one word (two
bytes) of data or more, and a STOP condition. Figure 4
illustrates the proper frame format for writing one word
of data to the MAX9672/MAX9673/MAX9674. Figure 5
illustrates the frame format for writing n-bytes of data to
the MAX9672/MAX9673/MAX9674.
The slave address with the R/Wbit set to 0 indicates that
the master intends to write data to the MAX9672/
MAX9673/MAX9674. The MAX9672/MAX9673/MAX9674
acknowledge receipt of the address byte during the
master-generated ninth SCL pulse.
The second byte transmitted from the master config-
ures the MAX9672/MAX9673/MAX9674’s internal regis-
ter address pointer. The MAX9672/MAX9673/
MAX9674’s internal address pointer consists of the 6
LSBs of the second byte. The 2 MSBs of the second
byte (M1 and M0) are set to 00b when writing to the
internal registers. See the
Memory
section for more
details. The pointer tells the MAX9672/MAX9673/
MAX9674 where to write the next byte of data. An
acknowledge pulse is sent by the MAX9672/
MAX9673/MAX9674 upon receipt of the address point-
er data.
The third and fourth bytes sent to the MAX9672/
MAX9673/MAX9674 contain the data that is written to the
chosen register and which type of register it writes to,
volatile (DAC) or nonvolatile memory (MTP). See the
Registers
section for more details. An acknowledge pulse
1 WORD
ACKNOWLEDGE FROM
MAX9672/MAX9673/MAX9674
AAPA0
ACKNOWLEDGE FROM MAX9672/
MAX9673/MAX9674
R/W
S SLAVE ADDRESS REGISTER ADDRESS DATA BYTE 2
AUTOINCREMENT INTERNAL REGISTER ADDRESS POINTER
A 0 0 DATA BYTE 1
W1 W0 D9 D8XXXXD7D6D1D0D2D4 D3D5
M0M1
ACKNOWLEDGE FROM MAX9672/
MAX9673/MAX9674
ACKNOWLEDGE FROM
MAX9672/MAX9673/MAX9674
Figure 4. Writing a Word of Data to the MAX9672/MAX9673/MAX9674
1 WORD
AAA0
ACKNOWLEDGE FROM
MAX9672/MAX9673/MAX9674
ACKNOWLEDGE FROM
MAX9672/MAX9673/MAX9674
R/W
S SLAVE ADDRESS REGISTER ADDRESS DATA BYTE 2
AUTOINCREMENT INTERNAL
REGISTER ADDRESS POINTER
A 0 0 DATA BYTE 1
ACKNOWLEDGE FROM MAX9672/
MAX9673/MAX9674
W1 W0 D9 D8XXXXD7D6D1D0D2D4 D3D5
1 WORD
AA
PDATA BYTE nDATA BYTE n-1
W1 W0 D9 D8XXXXD7D6D1D0D2D4 D3D5
M0M1
ACKNOWLEDGE FROM MAX9672/
MAX9673/MAX9674
ACKNOWLEDGE FROM MAX9672/
MAX9673/MAX9674
ACKNOWLEDGE FROM MAX9672/
MAX9673/MAX9674
Figure 5. Writing n Bytes of Data to the MAX9672/MAX9673/MAX9674
MAX9672/MAX9673/MAX9674
10-Bit, Programmable Gamma Reference
Systems with MTP for TFT LCDs
12 ______________________________________________________________________________________
from the MAX9672/MAX9673/MAX9674 signals receipt of
each data byte. The address pointer autoincrements to
the next register address after receiving every other data
byte. This autoincrement feature allows a master to write
to sequential register address locations within one contin-
uous frame. The master signals the end of transmission
by issuing a STOP condition.
If data is written into register address 0x1E, the address
pointer autoincrements to 0xFF and stays at 0xFF until
the master writes a new value into the register address
pointer.
Read Data Format
The master presets the address pointer by first sending
the MAX9672/MAX9673/MAX9674’s slave address with
the R/Wbit set to 0 followed by the register address
MTP FACTORY
INTIALIZATION VALUE
REGISTER
ADDRESS
REGISTER
NAME
REGISTER
DESCRIPTION
MAX9672 MAX9673 MAX9674
READ/
WRITE
0x00 GMA1 Gamma 1 0x3B0 0x3BA 0x3C2 Read and write
0x01 GMA2 Gamma 2 0x361 0x376 0x386 Read and write
0x02 GMA3 Gamma 3 0x312 0x332 0x34A Read and write
0x03 GMA4 Gamma 4 0x2C4 0x2EE 0x30E Read and write
0x04 GMA5 Gamma 5 0x275 0x2AA 0x2D2 Read and write
0x05 GMA6 Gamma 6 0x226 0x265 0x295 Read and write
0x06 GMA7 Gamma 7 0x1D8 0x221 0x259 Read and write
0x07 GMA8 Gamma 8 0x189 0x1DD 0x21D Read and write
0x08 GMA9 Gamma 9 0x13A 0x199 0x1E1 Read and write
0x09 GMA10 Gamma 10 0x0EC 0x155 0x1A5 Read and write
0x0A GMA11 Gamma 11 0x09D 0x110 0x169 Read and write
0x0B GMA12 Gamma 12 0x04E 0x0CC 0x12C Read and write
0x0C GMA13 Gamma 13 — 0x088 0X0F0 Read and write
0x0D GMA14 Gamma 14 — 0x044 0x0B4 Read and write
0x0E GMA15 Gamma 15 — — 0x078 Read and write
0x0F GMA16 Gamma 16 — — 0x03C Read and write
0x10 Reserved — — — — —
0x11 Reserved — — — — —
0x12 VCOM Common voltage 0x193 0x193 0x193 Read and write
0x13 Reserved — — — — —
0x14 Reserved — — — — —
0x15 Reserved — — — — —
0x16 Reserved — — — — —
0x17 Reserved — — — — —
0x18 VCOMMIN Minimum VCOM value 0x10D 0x10D 0x10D Read and write
0x19 VCOMMAX Maximum VCOM value 0x21A 0x21A 0x21A Read and write
0x1D Reserved,
DO NOT WRITE —————
0x1E Reserved,
DO NOT WRITE —————
Table 2. Register Map
MAX9672/MAX9673/MAX9674
10-Bit, Programmable Gamma Reference
Systems with MTP for TFT LCDs
______________________________________________________________________________________ 13
with M1 and M0 set to 00 after a START condition. The
MAX9672/MAX9673/MAX9674 acknowledge receipt of
its slave address and the register address by pulling
SDA low during the ninth SCL clock pulse. A REPEAT-
ED START condition is then sent followed by the slave
address with the R/Wbit set to 1. The MAX9672/
MAX9673/MAX9674 transmit the contents of the speci-
fied register. Transmitted data is valid on the rising
edge of the master-generated serial clock (SCL). The
address pointer autoincrements after every other read
data byte. This autoincrement feature allows all regis-
ters to be read sequentially within one continuous
frame. A STOP condition can be issued after any num-
ber of read data bytes. If a STOP condition is issued
followed by another read operation, the first data byte
to be read is from the register address location set by
the previous transaction and not 0x00. Subsequent
reads autoincrement the address pointer until the next
STOP condition. Attempting to read from register
addresses higher than 0x1E results in repeated reads
from a dummy register containing all one data. The
master acknowledges receipt of each read byte during
the acknowledge clock pulse. The master must
acknowledge all correctly received bytes except the
REG REG
ADDR B15 B14 B13 B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 B0
GMA1 0x00 W1 W0 X X X X b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
GMA2 0x01 W1 W0 X X X X b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
GMA3 0x02 W1 W0 X X X X b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
GMA4 0x03 W1 W0 X X X X b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
GMA5 0x04 W1 W0 X X X X b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
GMA6 0x05 W1 W0 X X X X b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
GMA7 0x06 W1 W0 X X X X b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
GMA8 0x07 W1 W0 X X X X b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
GMA9 0x08 W1 W0 X X X X b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
GMA10 0x09 W1 W0 X X X X b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
GMA11 0x0A W1 W0 X X X X b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
GMA12 0x0B W1 W0 X X X X b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
GMA13* 0x0C W1 W0 X X X X b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
GMA14* 0x0D W1 W0 X X X X b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
GMA15** 0x0E W1 W0 X X X X b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
GMA16** 0x0F W1 W0 X X X X b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
Reserved 0x10 ————————————————
Reserved 0x11 ————————————————
VCOM 0x12 W1 W0 X X X X b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
Reserved 0x13 ————————————————
Reserved 0x14 ————————————————
Reserved 0x15 ————————————————
Reserved 0x16 ————————————————
Reserved 0x17 ————————————————
VCOMMIN 0x18 W1 W0 X X X X b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
VCOMMAX 0x19 W1 W0 X X X X b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
Reserved
DO NOT
WRITE
0x1D ————————————————
Reserved
DO NOT
WRITE
0x1E ————————————————
Table 3. Register Description
*
Reserved for the MAX9672.
**
Reserved for the MAX9672/MAX9673.
MAX9672/MAX9673/MAX9674
10-Bit, Programmable Gamma Reference
Systems with MTP for TFT LCDs
14 ______________________________________________________________________________________
last byte. The final byte must be followed by a not
acknowledge from the master and then a STOP condi-
tion. Figures 6 and 7 illustrate the frame format for read-
ing data from the MAX9672/MAX9673/MAX9674.
Registers
Register Map
The MAX9672/MAX9673/MAX9674 have a bank of non-
volatile MTP memory and two banks of volatile memory
comprised of I2C registers and DAC registers. Each
memory location whether in nonvolatile or volatile mem-
ory holds a 10-bit word. Two bytes must be read or writ-
ten through the I2C interface for every 10-bit word.
Table 2 shows the register map. The same register
address and register name exists in the MTP memory
bank, I2C register bank, and the DAC register bank.
The write control bits determine which memory location
the data is stored into.
Register Description
Only the 10 LSBs are written to the registers (see Table
3). During a write operation, the write control bits (the 2
MSBs) are stripped from the incoming data stream and
are used to determine whether the MTP or DAC regis-
ters are updated (see Table 4).
VCOM Programmable Range
The MAX9672/MAX9673/MAX9674 feature the program-
mable range for VCOM. VCOMMIN and VCOMMAX
registers provide low and high limits for the VCOM DAC
register. At the factory, VCOMMIN is set to 0 and
VCOMMAX is set to 1023 (default values) to provide the
full rail-to-rail programmable range for VCOM. Later,
users can define their own limits by programming
VCOMMIN and VCOMMAX registers and MTP.
VCOM register values are limited to the defined range.
This means if the VCOM register accidentally gets pro-
grammed with a value higher than VCOMMAX, it auto-
matically gets locked to the VCOMMAX value. The I2C
bus does acknowledge and receive the data sent on
the bus. However, internally the part recognizes that the
value is outside of the range and adjusts it accordingly.
The same scenario is true if the value programming
VCOM is below VCOMMIN.
Memory
The MAX9672/MAX9673/MAX9674 include both volatile
memory (I2C and DAC) and nonvolatile memory (MTP).
It is possible to write to each single DAC memory loca-
tion from an MTP memory location individually or to
write to all at once. This is done with memory write bits
(M1, M0) that are the 2 MSBs of the register address
byte. Table 5 shows the memory write bits. Set both M1
and M0 to low or high when writing to or reading from
the register values through the I2C bus.
Volatile Memory
The MAX9672/MAX9673/MAX9674 feature a double-
buffered register structure. The volatile (DAC) memory
can be updated without updating the output voltage.
Figure 8 shows how to program a single DAC. The out-
put voltage is updated after sending the LSB (D0).
W1 W0 ACTION
0 0 No update.
0 1 All MTP registers get updated when the current I2C register has finished updating (end of B0).
1 0 All DAC registers get updated when the current I2C register has finished updating (end of B0).
1 1 No update.
Table 4. Write Control Bits
M1 M0 ACTION
0 0 None.
0 1 Only the addressed I2C registers and DAC registers get set to the MTP values.
1 0 All I2C registers and DAC registers get set to the MTP values.
1 1 None.
Table 5. Memory Write Bits
MAX9672/MAX9673/MAX9674
10-Bit, Programmable Gamma Reference
Systems with MTP for TFT LCDs
______________________________________________________________________________________ 15
A0 Sr
R/W
S SLAVE ADDRESS REGISTER ADDRESS
AUTOINCREMENT INTERNAL
REGISTER ADDRESS POINTER
A00
1 WORD
NOT ACKNOWLEDGE FROM MASTER
AAPDATA BYTE 2DATA BYTE 1
ACKNOWLEDGE FROM MASTER
X X D9 D8XXXXD7D6D1D0D2D4 D3D5
M0M1
1
R/W
SLAVE ADDRESS A
REPEATED START
ACKNOWLEDGE FROM MAX9672/
MAX9673/MAX9674 ACKNOWLEDGE FROM MAX9672/
MAX9673/MAX9674
ACKNOWLEDGE FROM MAX9672/
MAX9673/MAX9674
Figure 6. Reading One Indexed Word of Data from the MAX9672/MAX9673/MAX9674
A0 Sr
R/W
S SLAVE ADDRESS REGISTER ADDRESSA00
1 WORD
NOT ACKNOWLEDGE FROM MASTER
AAPDATA BYTE nDATA BYTE n-1
ACKNOWLEDGE FROM MASTER
X X D9 D8XXXXD7D6D1D0D2D4 D3D5
M0M1
1
R/W
SLAVE ADDRESS A
AUTOINCREMENT INTERNAL
REGISTER ADDRESS POINTER
1 WORD
ACKNOWLEDGE FROM MASTER
AADATA BYTE 2DATA BYTE 1
ACKNOWLEDGE FROM MASTER
X X D9 D8XXXXD7D6D1D0D2D4 D3D5
REPEATED START
ACKNOWLEDGE FROM MAX9672/
MAX9673/MAX9674
ACKNOWLEDGE FROM MAX9672/
MAX9673/MAX9674
ACKNOWLEDGE FROM MAX9672/
MAX9673/MAX9674
Figure 7. Reading n Bytes of Indexed Data from the MAX9672/MAX9673/MAX9674
MAX9672/MAX9673/MAX9674
10-Bit, Programmable Gamma Reference
Systems with MTP for TFT LCDs
16 ______________________________________________________________________________________
It is possible to write to multiple DACs first then update
the output voltage of all channels simultaneously, as
shown in Figure 9. In this mode, it is possible for the I2C
master to write to all registers of the MAX9672/
MAX9673/MAX9674 (Gamma and VCOM) in one commu-
nication. In that case, the value programmed on address-
es 0x10, 0x11, and 0x13 through 0x17 are meaningless.
However, the MAX9672/MAX9673/MAX9674 send an
acknowledge bit for each of the 2 bytes on any of these
addresses. The control bits (W1, W0) shown in Figure 9
are set in a way that all DACs are programmed to their
desired value with no changes to the output voltages until
the LSB of the last DAC is received and then all the chan-
nels are updated simultaneously.
Nonvolatile Memory
The MAX9672/MAX9673/MAX9674 are able to write to
nonvolatile memory (MTP) of any single DAC/VCOM reg-
ister in a single or burst I2C transaction. This memory
can be written to at least 300 times. Figure 10 shows a
single write to a MTP address. The control bits on Figure
10 set in a way that the MTP register is updated at the
end of the LSB (D0).
Figure 11 shows how to program multiple MTP registers
in one communication transition. Similar to program-
ming the volatile memory, the first 2 bytes of data corre-
spond to the DAC/VCOM address specified by the
master on the previous byte and the following 2 bytes
of data correspond to the next address and so on. In
this configuration all the MTP registers are programmed
at the same time following the LSB of the last set of
data bytes. (The last set of data bytes is different than
the previous bytes as it is bits 15 and 14.) If for some
reason the master issues a STOP condition before
sending the last 2 bytes of the data with appropriate
values of bits 15 and 14 (01), then none of the MTP reg-
isters are updated.
SLAVE ID DAC/VCOM ADDRESSM1
SR/W
= 0 A1 1 1 0 1 0 B1 0 0 D5D4D3D2D1D0 A
M0
A1 0 X X X X D9 D7 D6 D5 D4 D3 D2 D1 D0 A PD8
DATA DATA
Figure 8. Single DAC Programming
SLAVE ID DAC/VCOM ADDRESSM1
SR/W
= 0 A1 1 1 0 1 0 B1 0 0 D5D4D3D2D1D0 A
M0
A0 0 X X X X D9 D7 D6 D5 D4 D3 D2 D1 D0 AD8
DATA DATA
A0 0 X X X X D9 D7 D6 D5 D4 D3 D2 D1 D0 AD8
DATA DATA
A1 0 X X X X D9 D7 D6 D5 D4 D3 D2 D1 D0 A PD8
DATA DATA
Figure 9. Multiple (or All) DACs Programming
MAX9672/MAX9673/MAX9674
10-Bit, Programmable Gamma Reference
Systems with MTP for TFT LCDs
______________________________________________________________________________________ 17
Programming the MTP registers also updates the
DACs/VCOM volatile memory as well as the output volt-
ages. Similar to multiple volatile memory programming,
the update only occurs after the LSB of the last byte is
received. All the outputs are programmed and updated
simultaneously. However, depending on the number of
MTP registers, it takes 31ms to 500ms to store the val-
ues into the nonvolatile memory. During this time, the
MAX9672/MAX9673/MAX9674 are not available on the
I2C and any communication from the master should be
delayed until the MTP is programmed. Any attempt
from the I2C master to talk to the MAX9672/MAX9673/
MAX9674 is not acknowledged.
General and Single Acquire Commands
It is possible to update all the DAC outputs to the previ-
ously stored MTP values with one special command.
Set the 2 MSBs (M1 and M0) of the DAC/VCOM
address to 10 to set all the DACs and the output volt-
ages to the values of MTP (as shown in Figure 12). The
MAX9672/MAX9673/MAX9674 ignore the DAC/VCOM
address in this case.
It is also possible to update the DAC and output volt-
age of only one channel from the MTP. Set the 2 MSBs
(M1 and M0) of the DAC/VCOM address to 01 (as
shown in Figure 13) to move a specific value from MTP
into the DAC and output voltage of a single channel.
The MAX9672/MAX9673/MAX9674 feature a double-
buffered register structure. It is important to note that
updating the volatile (DAC) memory is not the same as
updating the output voltage. It is possible to write to
multiple DACs first then update the output voltage of all
channels simultaneously.
SLAVE ID DAC/VCOM ADDRESSM1
SR/W
= 0 A1 1 1 0 1 0 B1 0 0 D5D4D3D2D1D0 A
M0
A0 1 X X X X D9 D7 D6 D5 D4 D3 D2 D1 D0 A PD8
DATA DATA
Figure 10. Single MTP Programming
SLAVE ID DAC/VCOM ADDRESSM1
SR/W
= 0 A1 1 1 0 1 0 B1 0 0 D5D4D3D2D1D0 A
M0
A0 0 X X X X D9 D7 D6 D5 D4 D3 D2 D1 D0 AD8
DATA DATA
A0 0 X X X X D9 D7 D6 D5 D4 D3 D2 D1 D0 AD8
DATA DATA
A0 1 X X X X D9 D7 D6 D5 D4 D3 D2 D1 D0 A PD8
DATA DATA
Figure 11. Multiple MTP Programming
MAX9672/MAX9673/MAX9674
10-Bit, Programmable Gamma Reference
Systems with MTP for TFT LCDs
18 ______________________________________________________________________________________
Applications Information
Driving the Resistor Ladders
with More Current
If the gamma buffers cannot provide enough current to
drive the ends of the resistor ladders, then attach an
additional resistor from the nearest supply. For example,
at the very top of the resistor ladder, attach an additional
resistor to AVDD. At the very bottom of the resistor lad-
der, attach an additional resistor to GND. The
MAX9672/MAX9673/MAX9674 greatly diminish any
noise from AVDD supply through the discrete resistor
because the high-frequency noise from AVDD has been
attenuated, and the buffers have excellent AC PSRR.
See Figure 14.
VCOM Operational Amplifier
with Feedback Resistors
The output (VCOM) and negative input (VCOM_FB) of
the operational amplifier would usually be connected
together, resulting in a unity-gain configuration. If a
higher, closed-loop gain is desired, add feedback
resistors as shown in Figure 15.
Power-Up and Power-Down
Figures 16 and 17 show the proper startup sequence of
the MAX9672/MAX9673/MAX9674. The digital supply
must be powered up first. The analog supply should not
be powered up for at least 250µs (typ) after the digital
supply has been powered up. During this time, the MTP
register values are overwriting the default values in the
I2C registers. Once AVDD is above approximately 8V,
the output buffers have enough headroom to power up.
If REF is powered up after AVDD, then the outputs track
REF. If REF is powered up before AVDD, then the out-
puts track AVDD.
For power-down, AVDD and REF must be powered down
first to 0V, and then DVDD can safely be powered down.
Power Supplies and Bypass Capacitors
The MAX9672/MAX9673/MAX9674 operate from a sin-
gle 9V to 20V analog supply (AVDD) and a 2.7V to 3.6V
digital supply (DVDD). Bypass AVDD to GND with
0.1µF and 10µF capacitors in parallel. Use an extensive
ground plane to ensure optimum performance. Bypass
DVDD to GND with a 0.1µF capacitor. The 0.1µF
bypass capacitors should be as close as possible to
the device.
Refer to the MAX9672/MAX9673/MAX9674 evaluation
kit for a proven PCB layout.
Layout and Grounding
Exposed Pad
If the MAX9672/MAX9673/MAX9674 are mounted using
reflow soldering or wave soldering, the ground via(s) for
the exposed pad should have a finished hole size of at
least 14 mils to insure adequate wicking of soldering
onto the exposed pad. If the MAX9672/MAX9673/
MAX9674 are mounted using the solder mask tech-
nique, the via requirement does not apply. In either
case, the exposed pad must be connected to both digi-
tal and analog grounds through a low thermal resis-
tance path to ensure adequate heat dissipation. Do not
route traces under these packages.
SLAVE ID M1
SR/W
= 0 A111010B1 10000000A
M0
P
Figure 12. General Acquire Command to Update All Outputs with MTP
SLAVE ID DAC/VCOM ADDRESSM1
SR/W
= 0 A1 1 1 0 1 0 B1 0 1 D5D4D3D2D1D0 A
M0
P
Figure 13. Single Acquire Command to Update One Output with MTP
MAX9672/MAX9673/MAX9674
10-Bit, Programmable Gamma Reference
Systems with MTP for TFT LCDs
______________________________________________________________________________________ 19
MAX9672
MAX9673
MAX9674
DAC
REGISTERS
SOURCE
DRIVER
I2C
REGISTERS
I2C
INTERFACE
LCD PANEL
MTP
MEMORY
10-BIT
DAC
10 GMA1
REF
10
10-BIT
DAC
10 GMA2
10
10-BIT
DAC
10 GMA3
10
10-BIT
DAC
10 GMA4
10
10-BIT
DAC
10 GMA5
10
10-BIT
DAC
10 GMA6
10
10-BIT
DAC
10 GMA7
10
10-BIT
DAC
10 GMA8
10
10-BIT
DAC
10 GMA9
10
10-BIT
DAC
10 GMA10
10
10-BIT
DAC
10 GMA11
10
10-BIT
DAC
10 GMA12
10
10-BIT
DAC
10 GMA13*
10
10-BIT
DAC
10 GMA14*
10
10-BIT
DAC
10 GMA15**
10
10-BIT
DAC
10 GMA16**
18V
DVDD
SDA
SCL
A0
GND
10
10-BIT
DAC
10
AVDD_AMP
AGND_AMP
VCOM_FB
VCOM
10
GND
AVDD
*NOT AVAILABLE FOR THE MAX9672.
**NOT AVAILABLE FOR THE MAX9672/MAX9673.
18V
Figure 14. Typical Application Circuit with Additional Pullup and Pulldown Resistors on GMA1 and GMA16, Respectively
MAX9672/MAX9673/MAX9674
10-Bit, Programmable Gamma Reference
Systems with MTP for TFT LCDs
20 ______________________________________________________________________________________
VCOM
VCOM_FB
Figure 15. VCOM Operational Amplifier with Feedback Resistors
AVDD
REF
DVDD
4ms/div
0V
5V/div
GMA6
Figure 16. Recommended Power-Up Sequence
REF
VAVDD = 16.0V
VDVDD = 3.3V
GMA6
GMA1
GMA12
4ms/div
0V
5V/div
Figure 17. REF Powered Up After AVDD and DVDD
Chip Information
PROCESS: BiCMOS
MAX9672/MAX9673/MAX9674
10-Bit, Programmable Gamma Reference
Systems with MTP for TFT LCDs
______________________________________________________________________________________ 21
MAX9672
MAX9673
MAX9674
DAC
REGISTERS
SOURCE
DRIVER
I2C
REGISTERS
I2C
INTERFACE
LCD PANEL
MTP
MEMORY
10-BIT
DAC
10 GMA1
10
10-BIT
DAC
10 GMA2
10
10-BIT
DAC
10 GMA3
10
10-BIT
DAC
10 GMA4
10
10-BIT
DAC
10 GMA5
10
10-BIT
DAC
10 GMA6
10
10-BIT
DAC
10 GMA7
10
10-BIT
DAC
10 GMA8
10
10-BIT
DAC
10 GMA9
10
10-BIT
DAC
10 GMA10
10
10-BIT
DAC
10 GMA11
10
10-BIT
DAC
10 GMA12
10
10-BIT
DAC
10 GMA13*
10
10-BIT
DAC
10 GMA14*
10
10-BIT
DAC
10 GMA15**
10
10-BIT
DAC
10 GMA16**
18V
DVDD
SDA
SCL
A0
GND
10
10-BIT
DAC
10
AVDD_AMP
AGND_AMP
VCOM_FB
VCOM
10
GND
*NOT AVAILABLE FOR THE MAX9672.
**NOT AVAILABLE FOR THE MAX9672/MAX9673.
REF
AVDD
18V
Typical Operating Circuit
MAX9672/MAX9673/MAX9674
10-Bit, Programmable Gamma Reference
Systems with MTP for TFT LCDs
22 ______________________________________________________________________________________
Package Information
For the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages. Note that a “+”, “#”, or
“-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing per-
tains to the package regardless of RoHS status.
QFN THIN.EPS
PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND
PATTERN NO.
28 TQFN-EP T2855+8 21-0140 90-0028
MAX9672/MAX9673/MAX9674
10-Bit, Programmable Gamma Reference
Systems with MTP for TFT LCDs
______________________________________________________________________________________ 23
Package Information (continued)
For the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages. Note that a “+”, “#”, or
“-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing per-
tains to the package regardless of RoHS status.
MAX9669
10-Bit, Programmable Gamma Reference
Systems with MTP for TFT LCDs
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
24
____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2011 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.
Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
0 9/09 Initial release —
1 10/09 MTP factory initialization values changed per customer request in Table 3 12
2 11/09 Updated write operations and soldering temperature (reflow) 1, 2, 8, 16
3 3/10 Added lead temperature and made various corrections 2, 3, 4, 6, 8, 11,
14, 19, 21
4 2/11 Changed MTP factory initialization value of MAX9673 for GMA5 12
