AMS9491AN - Advanced Monolithic Systems

Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723

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 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 TEMPERATURE RANGE

±10mV AMS9491AN AMS9491AS 0 to 70° C

±20mV

AMS9491BN AMS9491BS 0 to 70° C

PIN CONNECTIONS

TO-92 8L SOIC

Plastic Package (N) SO Package (S)

13

1 2

8

43

7 56

N/C N/CN/C

N/C N/C N/C

+

-

Bottom View Top View

Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723

AMS9491

ABSOLUTE MAXIMUM RATINGS (Note 1)

Reverse Current 30mA Soldering information

Forward Current 10mA TO-92 package: 10 sec. 300°C

Operating Temperature Range 0°C to 70°C SOIC package: Vapor phase (60 sec) 215°C

Storage temperature -55°C to +150°C Infrared (15 sec.) 220°C

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

V

Reverse Dynamic Impedance

(Note 4) IR - 100 µA, f =20Hz 0.2 0.6 0.2 0.6 Ω

Reverse Breakdown Voltage

Change with current (Note 4) 10µA ≤IR ≤1mA

1mA ≤IR ≤20mA 2.0

20 2.0

20 mV

Min. Operating Current (Note 4) 8 10

20 8 10

20 µA

Wide Band Noise

(Note 5)

IR - 100 µA,

10Hz ≤ f ≤ 10kHz 60 60 µV

Temperature Coeff.

(Note 6)

50 100 ppm/°C

Long Term Stability

(Note 5) TA=25°C±.1°C

T = 1000 Hr 20 20 ppm

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 JA (junction to ambient) 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 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.

Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723

AMS9491

TYPICAL APPLICATIONS

Wide Input Micropower Reference Reference from

Range Reference from 9V Battery 1.5V Battery

4.3k

LM334

OUT

1.24V

AMS9491

V

IN

= 2.3V TO 30V

AMS9491

1.2V

500k

9V

AMS9491

1.2V

3k

1.5V

0°°C - 100°°C Thermometer Lower Power Thermometer 0°°C - 100°°C Thermometer

AMS9491

150

R1

4k

R2

1k

R3

100

R4

220

1.5V

(1.3-1.6V)†

R

V-

V+

LM334

M

0-100µA

IOUT

Calibration

1. Short AMS9491, adjust R3 for IOUT = temp at

1µA/°K

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

† IQ at 1.3V ≅ 500 µA

IQ at 1.6V ≅ 2.4mA

LM334

M

AMS9491

1.3 TO

1.6V‡

*

8k TO

12k†

* 2N3638 or 2N2907 select for inverse HFE ≅ 5

† Select for operation at 1.3V

‡ IQ ≅ 600µA to 900 µA

AMS9491

150

R1

2k

R2

1k

R3

50

R4

100

1.3-1.6V

R

V-

V+

LM334

M

0-50µA

IOUT

Calibration

1. Short AMS9491, adjust R3 for IOUT

= temp at

1.8µA/°K

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

Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723

AMS9491

TYPICAL APPLICATIONS (Continued)

Centigrade Thermometer Micropower* 10V Reference

AMS9491

V+

V-

R

R1

1k

V1 V2

LM334 90k 25k

27k

1.2k

2.3k

OUTPUT

1mV/° C

2.2k

1.5V†

Calibration

1. Adjust R1 so that V1 = temp at 1mV/°K.

2. Adjust V2 to 273.2mV.

† IQ for 1.3V to 1.6V battery voltage = 50µA to 150µA

150pF

AMS9491

3.5M

500k

22M

1M

7

4

6

3

2

-

+

VIN = 15V

IQ

10VLM4250C 8

*IQ ≅ 20µA standby current

Micropower Thermocouple Cold Junction Compensator

+

LM334

AMS9491

R1

R2

ZERO ADJ

100k

1M

1%

5.1k 2k

1%

TC ADJ

500

METER

MERCURY

CELL

1.345V

+

-

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 40.8 408 953Ω 12.17 11.17

S 6.4 63.4 150Ω 1.908 1.766

Typical supply current 50µA

Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723

AMS9491

TYPICAL APPLICATIONS (Continued)

Precision 1µµA to 1mA Current Sources

7

4

3

2

+

-

LM312 6

AMS9491

R2

R1

100k

-30V

-1.5V TO -27V

C1

150pF

IOUT*

*IOUT =1.23V/R2

7

4

3

2

+

-

LM312 6

R2

R1

100k

30V

1.5V TO 27V

C1

150pF

IOUT*

AMS9491

Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723

AMS9491

TYPICAL PERFORMANCE CHARACTERISTICS

-2

2

4

8

10

0.1 1 10 100

Reverse Characteristics

0

6

OUTPUT VOLTAGE CHANGE (mV)

T

A

=25° C

0.1

100

0.1 1 10 100

Reverse Dynamic Impedance

1

10

DYNAMIC IMPEDANCE (

Ω

)

0.01 0

0.4

1.2

0.1 1 10 100

0.8

0.01

REVERSE CURRENT (mA)

00.2 0.4 0.6 0.8 1.0 1.2

0.1

100

10

1.4

REVERSE VOLTAGE (V)

REVERSE CURRENT (

µ

A)

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

1.260

1.240

125

REFERENCE VOLTAGE (V)

Temperature Drift of 3

Representative Units

0

10

0

1.0

2.0

0200 400 600

TIME (

µ

s)

Response Time

VOLTAGE SWING (V)

0.5

1.5

~

0

200

400

600

700

100 1k 10k 100k

Noise Voltage

100

500

NOISE (nV/

√

Hz)

I

R

= 100

µ

A

10 FREQUENCY (Hz)

300

100 1k 10k 100k

CUTOFF FREQUENCY (Hz)

INTEGRATED NOISE (

µ

V)

0

10

20

30

40

50

60

70

TEMPERATURE (° C)

1.250

1.230

1.220

-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

AMS9491

OUTPUT

100k

INPUT

OUTPUT

INPUT

SINGLE POLE LOW PASS

SHARP CUTOFF

FILTER

Filtered Output Noise

0.01

Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723

AMS9491

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