Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140
Advanced AMS285-2.5/AMS385-2.5
Monolithic MICROPOWER VOLTAGE REFERENCE DIODE
Systems
FEATURES APPLICATIONS
•• ±20 mV (±0.8%) max. initial tolerance (A grade) •• Battery Powered Systems
•• Operating Current 20µµA to 20mA •• Instrumentation
•• Low Voltage Reference 2.5V •• A/D, D/A Converters
•• Max. 0.6ΩΩ Dynamic Impedance (A grade) •• Temperature measurement
•• Low Temperature Coefficient •• Current sources
•• 1.2V Device and Adjustable Device also available •• Notebook/Personal Computer
AMS285-1.2 and AMS285 series, respectively •• Monitors/ VCR/ TV
AMS385-1.2 and AMS385 series. •• Pagers
GENERAL DESCRIPTION
The AMS285-2.5/AMS385-2.5 are two-terminal micropower band-gap voltage reference diodes. They feature a very low
dynamic impedance and good temperature coefficient, operating over a 20µA to 20mA current range. On-chip trimming is
used to provide tight voltage tolerance. Since the AMS285-2.5/AMS385-2.5 is a band-gap reference, uses only transistors and
resistors, low noise and good long term stability result. Careful design of the AMS285-2.5/AMS385-2.5 has made the device
exceptionally tolerant of capacitive loading, making it easy to use in almost any reference application. The wide dynamic
operating range allows its use with widely varying supplies with excellent regulation. The extremely low power drain of the
AMS285-2.5/AMS385-2.5 makes these reference diodes useful for micropower circuitry. These voltage references can be
used to make portable meters, regulators or general purpose analog circuitry with battery life approaching shelf life. Further
more, the wide operating current allows it to replace older references with a tight tolerance part.
The AMS285-2.5 is operational in the full industrial temperature range of -40°C to 85°C while AMS385-2.5 is operating
over a 0°C to 70°C temperature range. The AMS285-2.5/AMS385-2.5 are available in TO-92, SO-8 and SOT-89 packages.
ORDERING INFORMATION:
TOL. PACKAGE TYPE OPERATING
TO-92 8 LEAD SOIC SOT-89 TEMPERATURE RANGE
±20mV AMS285-2.5AN AMS285-2.5AS AMS285-2.5AL -40 to 85° C
±38mV AMS285-2.5BN AMS285-2.5BS AMS285-2.5BL -40 to 85° C
±75mV AMS285-2.5CN AMS285-2.5CS AMS285-2.5CL -40 to 85° C
±20mV AMS385-2.5AN AMS385-2.5AS AMS385-2.5AL 0 to 70° C
±38mV AMS385-2.5BN AMS385-2.5BS AMS385-2.5BL 0 to 70° C
±75mV AMS385-2.5CN AMS385-2.5CS AMS385-2.5CL 0 to 70° C
Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140
AMS285-2.5/AMS385-2.5
ABSOLUTE MAXIMUM RATINGS
Reverse Current 30mA Storage temperature -55°C to +150°C
Forward Current 10mA Soldering information
Operating Temperature Range TO-92 package: 10 sec. 260°C
AMS285-2.5 -40°C to 85°C SOIC package: Vapor phase (60 sec) 215°C
AMS385-2.5 0°C to 70°C Infrared (15 sec.) 220°C
SOT-89 package: 10 sec. 265°C
ELECTRICAL CHARACTERISTICS
Electrical Characteristics at IR = 100 µA, and TA = +25°C unless otherwise specified.
Parameter Conditions AMS285A-2.5
Min Typ Max AMS285B-2.5
Min Typ Max AMS285C-2.5
Min Typ Max Units
Reverse Breakdown
Voltage (Note 4) IR - 100 µA2.480 2.500 2.520 2.462 2.500 2.538 2.425 2.500 2.575 V
Reverse Dynamic
Impedance (Note 4) IR - 100 µA, f =20Hz 0.2 0.60 1 1 Ω
Reverse Breakdown
Voltage Change with
current (Note 4)
10µA ≤IR ≤1mA
1mA ≤IR ≤20mA
1.0
10 1.0
10 2.0
20 mV
Min. Operating
Current (Note 4) 12 18
20 13 20
30 13 20
30 µA
µA
Wide Band Noise
(Note 5)
IR - 100 µA,
10Hz ≤ f ≤ 10kHz 120 120 120 µV
Temperature Coeff.
(Note 6) 25 50 100 150 ppm/°C
Long Term Stability
(Note 5) TA=25°C±.1°C
T = 1000 Hr 20 20 20 ppm
ELECTRICAL CHARACTERISTICS
Electrical Characteristics at IR = 100 µA, and TA = +25°C unless otherwise specified.
Parameter Conditions AMS385A-2.5
Min Typ Max AMS385B-2.5
Min Typ Max AMS385C-2.5
Min Typ Max Units
Reverse Breakdown
Voltage (Note 4) IR - 100 µA2.480 2.500 2.520 2.462 2.500 2.538 2.425 2.500 2.575 V
Reverse Dynamic
Impedance (Note 4) IR - 100 µA, f =20Hz 0.2 0.60 1 1 Ω
Reverse Breakdown
Voltage Change with
Current (Note 4)
10µA ≤IR ≤1mA
1mA ≤IR ≤20mA
1.0
10 2.0
20 2.0
20 mV
Min. Operating
Current (Note 4) 12 18
20 13 20
30 13 20
30 µA
µA
Wide Band Noise
(Note 5)
IR - 100 µA,
10Hz ≤ f ≤ 10kHz 120 120 120 µV
Temperature Coeff.
(Note 6) 25 50 100 150 ppm/°C
Long Term Stability
(Note 5) TA=25°C±.1°C
T = 1000 Hr 20 20 20 ppm
Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140
AMS285-2.5/AMS385-2.5
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The
guaranteed specifications apply only for the test conditions listed.
Note 2: For elevated temperature operation, Tj max is:
AMS285 +125°C
AMS385 +100°C
Thermal Resistance TO-92 SO-8 SOT-89
ϕ JA (junction to ambient) 170°C/W (0.125” leads) 165°C/W 160°C/W
Note 3: Parameters identified with boldface type apply at temperature extremes. All other numbers apply at TA = TJ = 25°C.
Note 4: Guaranteed and 100% production tested.
Note 5: Guaranteed but not 100% production tested. These limits are not used to calculate average outgoing quality levels.
Note 6: The average temperature coefficient is defined as the maximum deviation of reference voltage at all measured temperatures between the operating TMAX and
TMIN, divided by TMAX - TMIN. The measured temperatures are 0°C, 25°C, 70°C and 85°C.
PIN CONNECTIONS
TO-92 8L SOIC SOT-89
Plastic Package (N) SO Package (S) (L)
123
1 2
8
43
7 56
N/C N/CN/C
N/C N/C N/C
+
-N/C -+
123
Bottom View Top View Top View
TYPICAL APPLICATIONS
Wide Input Micropower Reference
Range Reference from 9V Battery
3.3k
LM334
OUT
2.5V
AMS385-2.5
V
IN
= 3.7V TO 30V
AMS385-2.5
2.5V
200k
9V
Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140
AMS285-2.5/AMS385-2.5
TYPICAL APPLICATIONS (Continued)
0°°C - 100°°C Thermometer 0°°C - 100°°C Thermometer
AMS385-2.5
1k
R1
8k
R2
1k
R3
100
R4
220
3V
R
V-
V+
LM334
M
0-100µA
IOUT
Calibration
1. Short AMS385-2.5, adjust R3 for IOUT = temp at 1µA/°K
2. Remove short, adjust R2 for correct reading in °C
AMS385-2.5
150
R1
4k
R2
1k
R3
50
R4
100
3V
R
V-
V+
LM334
M
0-50µA
IOUT
Calibration
1. Short AMS385-2.5, adjust R3 for IOUT = temp at 1.8µA/°K
2. Remove short, adjust R2 for correct reading in °F
Micropower* 5V Regulator Micropower* 10V Reference
150pF
AMS385-2.5
100k
10M
2.2k
7
4
6
2
3
-
+
VIN ≥ 5.2V
IQ
VO = 5V
IL ≤ 100mA
LM4250C
8
R
V-
V+
LM334
2k 100k
47k
2N2905
1N457
1N457 +4.7µF
TANTALUM
*IQ ≅ 40µA
150pF
AMS385-2.5
1.5M
500k
22M
500k
7
4
6
3
2
-
+
VIN = 15V
IQ
10VLM4250C 8
*IQ ≅ 20µA standby current
Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140
AMS285-2.5/AMS385-2.5
TYPICAL APPLICATIONS (Continued)
Micropower Thermocouple Cold Junction Compensator
+
LM334
AMS385-2.5
R1
R2
ZERO ADJ
100k
1M
1%
18k 2k
1%
TC ADJ
500
METER
3V
LITHIUM
+
-
V+
V-
R
THERMOCOUPLE +
-
COLD JUNCTION
ISO THERMAL
WITH LM334
Adjustment Procedure
1. Adjust TC ADJ pot until voltage across R1 equals Kelvin temperature
multiplied by the thermocouple Seebeck coefficient.
2. Adjust ZERO ADJ pot until voltage across R2 equals the thermocouple
Seebeck coefficient multiplied by 273.2.
Thermocouple Seebeck R1 R2 Voltage Voltage
Type Coefficient (ΩΩ) (ΩΩ) Across R1 Across R2
(mV/ °°C) @ 25°°C (mV) (mV)
J 52.3 523 1.24k 15.60 14.32
T 42.8 432 1k 12.77 11.78
K 40.8 412 953Ω 12.17 11.17
S 6.4 63.4 150Ω 1.908 1.766
Typical supply current 50µA
Precision 1µµA to 1mA Current Sources
7
4
3
2
+
-
LM312 6
AMS385-2.5
R2
R1
68k
-30V
-1.5V TO -27V
C1
150pF
IOUT*
*I
OUT
=2.5V/R2
7
4
3
2
+
-
LM312 6
R2
R1
68k
30V
1.5V TO 27V
C1
150pF
IOUT*
AMS385-2.5
Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140
AMS285-2.5/AMS385-2.5
TYPICAL PERFORMANCE CHARACTERISTICS
-4
4
8
16
0.1 1 10 100
Reverse Characteristics
0
OUTPUT VOLTAGE CHANGE (mV)
T
A
=25° C
0.1
1000
0.1 1 10 100
Reverse Dynamic Impedance
1
100
DYNAMIC IMPEDANCE (Ω)
0.01 0
0.4
1.6
0.1 1 10 100
0.8
0.01
REVERSE CURRENT (mA)
REVERSE CURRENT (mA)
00.5 1.0 1.5 2.0 2.5
0.1
100
10
3.0
REVERSE VOLTAGE (V)
REVERSE CURRENT (µA)
1
Reverse Characteristics Forward Characteristics
FORWARD CURRENT (mA)
FORWARD VOLTAGE (V)
10 100 1k 10k 100k
0.1
1k
10
Reverse Dynamic Impedance
1M
FREQUENCY (Hz)
DYNAMIC IMPEDANCE (Ω)
1
10k
100
-55 525 45 65 85 105
2.530
2.490
125
REFERENCE VOLTAGE (V)
Temperature Drift
0
10
0
1.0
3.0
0200 400 600
TIME (µs)
Response Time
VOLTAGE SWING (V)
2.0
~
~
~
~
0
400
800
1200
1400
100 1k 10k 100k
Noise Voltage
200
1000
NOISE (nV/√Hz)
I
R
= 100
µ
A
10 FREQUENCY (Hz)
600
100 1k 10k 100k
CUTOFF FREQUENCY (Hz)
INTEGRATED NOISE (µV)
0
20
40
60
80
100
120
TEMPERATURE (° C)
2.510
2.470
2.460
-35 -15
I
R
= 100
µ
A
T
A
=-55° C
T
A
=125° C
T
A
=125° C
T
A
=-55° C
T
A
=25° C
T
A
=-55° C
T
A
=25° C
T
A
=125° C
T
A
=25° C
I
R
= 100
µ
A
T
A
=-55° C
T
A
=25° C
T
A
=125° C
I
R
= 100
µ
A
100
µ
AOUTPUT
AMS385-2.5
OUTPUT
100k
INPUT
OUTPUT
INPUT
SINGLE POLE LOW PASS
SHARP CUTOFF
FILTER
Filtered Output Noise
0.01
10
12 1.2
2.520
2.500
2.480
2.450
Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140
AMS285-2.5/AMS385-2.5
PACKAGE DIMENSIONS inches (millimeters) unless otherwise noted.
3 LEAD TO-92 PLASTIC PACKAGE (N)
8 LEAD SOIC PLASTIC PACKAGE (S)
0.140±0.010
(3.556±0.127)
0.060±0.010
(1.524±0.254)
0.015±0.002
(0.381±0.051)
0.016±0.003
(0.406±0.076)
0.050±0.005
(1.270±0.127)
0.060±0.005
(1.524±0.127)
DIA
0.180±0.005
(4.572±0.127)
0.180±0.005
(4.572±0.127)
0.050
(1.270)
MAX
0.500
(12.70)
MIN UNCONTROLLED
LEAD DIMENSIONS
10°
NOM
5° NOM
N (TO-92 ) AMS DRW# 042391
0.90
(2.286)
NOM
0°-8° TYP
0.010-0.020
(0.254-0.508)
S (SO-8 ) AMS DRW# 042293
x 45°
0.016-0.050
(0.406-1.270)
0.008-0.010
(0.203-0.254)
0.004-0.010
(0.101-0.254)
0.014-0.019
(0.355-0.483)
0.053-0.069
(1.346-1.752)
0.050
(1.270)
TYP
0.150-0.157**
(3.810-3.988)
0.228-0.244
(5.791-6.197)
0.189-0.197*
(4.801-5.004)
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
1 2 3 4
8 7 6 5
Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140
AMS285-2.5/AMS385-2.5
PACKAGE DIMENSIONS inches (millimeters) unless otherwise noted (Continued).
SOT-89 PLASTIC PACKAGE (L)
0.090-0.102
(2.29-2.60)
0.173-0.181
(4.40-4.60)
0.064-0.072
(1.62-1.83)
0.155-0.167
(3.94-4.25)
0.059
(1.50)
BSC
0.035-0.047
(0.89-1.20)
L (SOT-89 ) AMS DRW# 042392
0.118
(3.00)
BSC
0.014-0.019
(0.36-0.48)
0.017-0.022
(0.44-0.56)
0.084-0.090
(2.13-2.29)
0.055-0.063
(1.40-1.60) 0.014-0.017
(0.35-0.44)
