Advanced Monolithic Systems AMS9491 Service Manual
http://www.BDTIC.com/AMS
Advanced AMS9491
Monolithic 1.235V VOLTAGE REFERENCE
Systems
RoHS compliant
FEATURES APPLICATIONS
• ±10 mV max. initial tolerance (A grade) • Battery Powered Systems
• Operating Current 10µA to 20mA • Instrumentation
• Low Voltage Reference 1.235 • A/D, D/A Converters
• Max. 0.6Ω Dynamic Impedance (A grade) • Temperature measurement
• Low Temperature Coefficient • Current sources
GENERAL DESCRIPTION
The AMS9491 is a two-terminal micropower band-gap voltage reference diode. It feature a very low dynamic impedance and
good temperature coefficient, operating over a 10µA to 20mA current range. On-chip trimming is used to provide tight voltage
tolerance. Since the AMS9491 is a band-gap reference, uses only transistors and resistors, low noise and good long-term
stability result. Careful design of the AMS9491 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 AMS9491 makes this reference diode useful for micropower
circuitry.
The AMS9491 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 AMS9491 is operating over a 0°C to 70°C temperature range and is available in TO-92 and SO-8 packages.
ORDERING INFORMATION:
TOL. PACKAGE TYPE OPERATING
TO-92 8 LEAD SOIC
±10mV AMS9491AN AMS9491AS
±20mV AMS9491BN AMS9491BS
PIN CONNECTIONS
TO-92 8L SOIC
Plastic Package (N) SO Package (S)
13
+
756
• Pagers
TEMPERATURE RANGE
0 to 70° C
0 to 70° C
N/C N/CN/C
Bottom View Top View
Advanced Monolithic Systems, Inc.
12843
N/C N/C N/C
-
AMS9491
http://www.BDTIC.com/AMS
ABSOLUTE MAXIMUM RATINGS (Note 1)
Reverse Current 30mA Soldering information (25 sec .)
Forward Current 10mA
Operating Temperature Range
Storage temperature
0°C to 70°C
-55°C to +150°C
ELECTRICAL CHARACTERISTICS
Electrical Characteristics at IR = 100 µA, and TA = +25°C unless otherwise specified.
Parameter Conditions AMS9491A AMS9491B Units
Reverse Breakdown Voltage
(Note 4)
Reverse Dynamic Impedance
(Note 4)
Reverse Breakdown Voltage
Change with current (Note 4)
Min. Operating Current (Note
4)
- 100 µA
I
R
- 100 µA, f =20Hz
I
R
10µA ≤I
1mA ≤I
≤1mA
R
≤20mA
R
Min Typ Max Min Typ Max
1.215
0.2 0.6 0.2 0.6
2.0
8 10
1.235
1.255
20
20
1.215
2.0
8 10
265°C
1.235
1.255
20
20
V
Ω
mV
µA
Wide Band Noise
(Note 5)
Temperature Coeff.
(Note 6)
Long Term Stability
(Note 5)
IR - 100 µA,
10Hz ≤ f ≤ 10kHz
=25°C±.1°C
T
A
T = 1000 Hr
60 60
50
20 20 ppm
100
ppm/°C
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: Thermal resistance is as follows:
Thermal Resistance TO-92 SO-8
ϕ
(junction to ambient)
JA
170°C/W (0.125” leads) 165°C/W
Note 3: Parameters identified with boldface type apply at temperature extremes. All other numbers apply at T
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
T
MAX and TMIN
, divided by T
MAX
- T
. The measured temperatures are 0°C, 25°C, 70°C.
MIN
= TJ = 25°C.
A
µV
Advanced Monolithic Systems, Inc.
AMS9491
http://www.BDTIC.com/AMS
TYPICAL APPLICATIONS
Wide Input Micropower Reference Reference from
Range Reference from 9V Battery 1.5V Battery
V
= 2.3V TO 30V
IN
9V
1.5V
LM334
4.3k
OUT
1.24V
AMS9491
0°C - 100°C Thermometer
150
M
0-100
µ
I
OUT
A
LM334
+
V
-
V
R1
4k
R2
1k
R
AMS9491
R3
100
R4
220
1.5V
(1.3-1.6V)†
Calibration
1. Short AMS9491, adjust R3 for I
= temp at
OUT
1µA/°K
2. Remove short, adjust R2 for correct reading in
°C
† IQ at 1.3V ≅ 500 µA
I
at 1.6V ≅ 2.4mA
Q
500k
1.2V
AMS9491
Lower Power Thermometer
*
M
LM334
AMS9491
* 2N3638 or 2N2907 select for inverse H
† Select for operation at 1.3V
≅ 600µA to 900 µA
‡ I
Q
3k
1.2V
AMS9491
0°C - 100°C Thermometer
150
1.3 TO
8k TO
12k†
FE
1.6V‡
≅ 5
M
0-50
µ
A
I
OUT
+
V
LM334
-
V
R1
2k
R2
1k
R
AMS9491
R3
50
R4
100
1.3-1.6V
Calibration
1. Short AMS9491, adjust R3 for I
= temp at
OUT
1.8µA/°K
2. Remove short, adjust R2 for correct reading in
°F
Advanced Monolithic Systems, Inc.
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