ADMOS AMS9491BS, AMS9491BN, AMS9491AS, AMS9491AN Datasheet

Advanced AMS9491
Monolithic 1.235V VOLTAGE REFERENCE
Systems

FEATURES APPLICATIONS

•• ±10 mV max. initial tolerance (A grade) •• Battery Powered Systems

•• Operating Current 10µµA to 20mA •• Instrumentation

•• Low Voltage Reference 1.235 •• A/D, D/A Converters

•• Max. 0.6ΩΩ Dynamic Impedance (A grade) •• Temperature measurement

•• Low Temperature Coefficient •• Current sources

•• Pagers

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 long­term 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

TEMPERATURE RANGE

0 to 70° C
0 to 70° C

PIN CONNECTIONS

TO-92 8L SOIC

Plastic Package (N) SO Package (S)

N/C N/CN/C

+

13

Bottom View Top View

8437 56

1 2

N/C N/C N/C

-

Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone [phone] Fax [phone]

AMS9491

ABSOLUTE MAXIMUM RATINGS (Note 1)

Reverse Current 30mA Soldering information
Forward Current 10mA TO-92 package: 10 sec.
Operating Temperature Range
Storage temperature

0°C to 70°C

-55°C to +150°C

SOIC package: Vapor phase (60 sec)
Infrared (15 sec.)

ELECTRICAL CHARACTERISTICS

Electrical Characteristics at IR = 100 µA, and TA = +25°C unless otherwise specified.

Parameter Conditions AMS9491A AMS9491B Units

Min Typ Max Min Typ Max

Reverse Breakdown Voltage
(Note 4)

IR - 100 µA

1.215 1.235 1.255 1.215 1.235 1.255

300°C
215°C
220°C

V

Reverse Dynamic Impedance
(Note 4)

Reverse Breakdown Voltage
Change with current (Note 4)

Min. Operating Current (Note 4) 8 10

Wide Band Noise
(Note 5)

Temperature Coeff.
(Note 6)

Long Term Stability
(Note 5)

IR - 100 µA, f =20Hz
10µA ≤IR ≤1mA

1mA ≤IR ≤20mA

IR - 100 µA,
10Hz ≤ f ≤ 10kHz

TA=25°C±.1°C
T = 1000 Hr

0.2 0.6 0.2 0.6

2.0
20

8 10

20

60 60

50 100

20 20 ppm

2.0
20

20

mV

µA

µV

ppm/°C

Ω

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

Note 3: Parameters identified with boldface type apply at temperature extremes. All other numbers apply at T

170°C/W (0.125” leads) 165°C/W

= TJ = 25°C.

A

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

T

, divided by T

MIN

MAX

- T

. The measured temperatures are 0°C, 25°C, 70°C.

MIN

MAX and

Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone [phone] Fax [phone]

TYPICAL APPLICATIONS

OUT

OUT

Wide Input Micropower Reference Reference from

Range Reference from 9V Battery 1.5V Battery

AMS9491

0°°C - 100°°C Thermometer

M

0-100µA

I

OUT

+

V

R

LM334

-

V

VIN = 2.3V TO 30V

LM334

AMS9491

150

R1
4k

R2
1k

AMS9491

R3
100

R4
220

4.3k

1.5V
(1.3-1.6V)†

OUT

1.24V

9V

500k

1.2V

AMS9491

Lower Power Thermometer

*

M

8k TO

LM334

AMS9491

12k†

* 2N3638 or 2N2907 select for inverse H

† Select for operation at 1.3V
‡ IQ ≅ 600µA to 900 µA

1.5V

3k

1.2V

AMS9491

0°°C - 100°°C Thermometer

150

1.3 TO

1.6V‡

≅ 5

FE

0-50µA

I

OUT

M

LM334

R1
2k

+

V

-

V

R2
1k

R

AMS9491

R3
50

R4
100

1.3-1.6V

Calibration

1. Short AMS9491, adjust R3 for I

= temp at

1µA/°K

2. Remove short, adjust R2 for correct reading in °C

Calibration

1. Short AMS9491, adjust R3 for I

= temp at

1.8µA/°K

2. Remove short, adjust R2 for correct reading in °F

† IQ at 1.3V ≅ 500 µA
IQ at 1.6V ≅ 2.4mA

Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone [phone] Fax [phone]