Datasheet LM385Z-1.2, LM385MX-1.2, LM385M3-1.2, LM385BXM-1.2, LM385BMX-1.2 Datasheet (NSC)

LM185-1.2/LM285-1.2/LM385-1.2
Micropower Voltage Reference Diode

General Description

The LM185-1.2/LM285-1.2/LM385-1.2 are micropower
2-terminal band-gap voltage regulator diodes. Operating
over a 10 µAto20mAcurrent range, they feature exception­ally low dynamic impedance and good temperature stability.
On-chip trimming is used to provide tight voltage tolerance.
Since the LM185-1.2 band-gap reference uses only transis­tors and resistors, low noise and good long term stability re­sult.

Careful design of the LM185-1.2 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 LM185-1.2 makes it
useful for micropower circuitry.This voltage reference can be
used to make portable meters, regulators or general purpose
analog circuitry with battery life approaching shelf life.

Further, the wide operating current allows it to replace older
references with a tighter tolerance part.

The LM185-1.2 is rated for operation over a −55˚C to 125˚C
temperature range while the LM285-1.2 is rated −40˚C to
85˚C and the LM385-1.2 0˚C to 70˚C. The LM185-1.2/
LM285-1.2 are available in a hermetic TO-46 package and
the LM285-1.2/LM385-1.2 are also available in a low-cost
TO-92 molded package, as well as SO and SOT-23. The
LM185-1.2 is also available in a hermetic leadless chip car­rier package.

Features

n

±

4mV(±0.3%) max. initial tolerance (A grade)

n Operating current of 10 µA to 20 mA
n 0.6Ω max dynamic impedance (A grade)
n Low temperature coefficient
n Low voltage reference—1.235V
n 2.5V device and adjustable device also available
n LM185-2.5 series and LM185 series, respectively

Connection Diagrams

T0-92

Plastic Package (Z)

DS005518-10

Bottom View

Order Number LM285Z-1.2,

LM285BXZ-1.2, LM285BYZ-1.2

LM385Z-1.2, LM385BZ-1.2

LM385BXZ-1.2 or LM385BYZ-1.2

See NS Package Number Z03A

SOT23

DS005518-33

*

Pin 3 is attached to the Die Attach Pad (DAP) and should be connected

to Pin 2 or left floating.

Order Number LM385M3-1.2

See NS Package Number MA03B

January 2000

LM185-1.2/LM285-1.2/LM385-1.2 Micropower Voltage Reference Diode

© 2000 National Semiconductor Corporation DS005518 www.national.com

Connection Diagrams (Continued)

SO Package

DS005518-9

Order Number LM285M-1.2,

LM285BXM-1.2, LM285BYM-1.2

LM385M-1.2, LM385BM-1.2

LM385BXM-1.2 or LM385BYM-1.2

See NS Package Number M08A

TO-46

Metal Can Package (H)

DS005518-6

Bottom View

Order Number LM185H-1.2, LM185H-1.2/883,

LM185BXH-1.2, LM185BYH-1.2

LM285H-1.2 or LM285BXH-1.2

See NS Package Number H02A

LM185-1.2/LM285-1.2/LM385-1.2

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Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.

(Note 2)
Reverse Current 30 mA

Forward Current 10 mA

Operating Temperature Range (Note 3)

LM185-1.2 −55˚C to +125˚C
LM285-1.2 −40˚C to +85˚C
LM385-1.2 0˚C to 70˚C

Storage Temperature −55˚C to +150˚C
Soldering Information

TO-92 package: 10 sec. 260˚C
TO-46 package:10 sec. 300˚C

SO and SOT Pkg.

Vapor phase (60 sec.) 215˚C
Infrared (15 sec.) 220˚C

See AN-450 “Surface Mounting Methods and Their Effect
on Product Reliability” for other methods of soldering
surface mount devices.

Electrical Characteristics (Note 4)

LM185-1.2
LM185BX-1.2 LM385B-1.2
LM185BY-1.2 LM385BX-1.2 LM385-1.2

LM285-1.2 LM385BY-1.2 Units

Parameter Conditions Typ LM285BX-1.2 (Limit)

LM285BY-1.2

Tested Design Tested Design Tested Design

Limit Limit Limit Limit Limit Limit

(Notes

5, 8)

(Note 6) (Note 5) (Note 6) (Note 5) (Note 6)

Reverse Breakdown T

A

=

25˚C, 1.235 1.223 1.223 1.205 V(Min)

Voltage 10 µA ≤ I

R

≤ 20 mA 1.247 1.247 1.260 V(Max)
Minimum Operating 8 10 20 15 20 15 20 µA
Current LM385M3-1.2 10 15 (Max)
Reverse Breakdown 10 µA ≤ I

R

≤ 1mA 1 1.5 1 1.5 1 1.5 mV
Voltage Change (Max)
with Current 1 mA ≤ I

R

≤ 20 mA 10 20 20 25 20 25 mV

(Max)

Reverse Dynamic I

R

=

100 µA, f=20 Hz 1 Ω
Impedance
Wideband Noise I

R

=

100 µA, 60 µV
(rms) 10 Hz ≤ f ≤ 10 kHz
Long Term Stability I

R

=

100 µA, T=1000 Hr, 20 ppm

T

A

=

25˚C

±

0.1˚C

Average Temperature I

R

=

100 µA
Coefficient (Note 7) X Suffix 30 30 ppm/˚C

Y Suffix 50 50 ppm/˚C
All Others 150 150 150 ppm/˚C

(Max)

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: Refer to RETS185H-1.2 for military specifications.
Note 3: For elevated temperature operation, T

j

max is:
LM185 150˚C
LM285 125˚C
LM385 100˚C

Thermal Resistance TO-92 TO-46 SO-8 SOT23

θ

JA

(junction to ambient) 180˚C/W (0.4" leads) 440˚C/W 165˚C/W 283˚C/W

170˚C/W (0.125" leads)

θ

JC

(junction to case) N/A 80˚C/W N/A N/A

Note 4: Parameters identified with boldface type apply at temperature extremes. All other numbers apply at T

A

=

T

J

=

25˚C.

LM185-1.2/LM285-1.2/LM385-1.2

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Electrical Characteristics (Note 4) (Continued)

Note 5: Guaranteed and 100%production tested.
Note 6: Guaranteed, but not 100%production tested. These limits are not used to calculate average outgoing quality levels.
Note 7: The average temperature coefficient is defined as the maximum deviation of reference voltage at all measured temperatures between the operating T

MAX

and T

MIN

, divided by T

MAX−TMIN

. The measured temperatures are −55˚C, −40˚C, 0˚C, 25˚C, 70˚C, 85˚C, 125˚C.

Note 8: A military RETS electrical specification is available on request.

Typical Performance Characteristics

Reverse Characteristics

DS005518-13

Reverse Characteristics

DS005518-14

Forward Characteristics

DS005518-15

Temperature Drift of 3
Representative Units

DS005518-16

Reverse Dynamic Impedance

DS005518-17

Reverse Dynamic Impedance

DS005518-18

Noise Voltage

DS005518-19

Filtered Output Noise

DS005518-20

Response Time

DS005518-21

LM185-1.2/LM285-1.2/LM385-1.2

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Typical Applications

Wide Input

Range Reference

DS005518-8

Micropower Reference

from 9V Battery

DS005518-22

Reference from

1.5V Battery

DS005518-23

Micropower*5V Regulator

DS005518-24

*I

Q

≅

30 µA

Micropower*10V Reference

DS005518-25

*I

Q

≅

20 µA standby current

Precision 1 µA to 1 mA Current Sources

DS005518-26

DS005518-27

LM185-1.2/LM285-1.2/LM385-1.2

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Typical Applications (Continued)

METER THERMOMETERS

0˚C−100˚C Thermometer

DS005518-28

Calibration

1. Short LM385-1.2, adjust R3 for I

OUT

=

temp at 1 µA/˚K

2. Remove short, adjust R2 for correct reading in centigrade

†

IQat 1.3V≅500 µA

I

Q

at 1.6V≅2.4 mA

Lower Power Thermometer

DS005518-29

*2N3638 or 2N2907 select for inverse H

FE

≅

5

†

Select for operation at 1.3V

‡

I

Q

≅

600 µA to 900 µA

0˚F−50˚F Thermometer

DS005518-30

Calibration

1. Short LM385-1.2, adjust R3 for I

OUT

=

temp at 1.8 µA/˚K

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

Micropower Thermocouple Cold Junction

Compensator

DS005518-31

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 (Ω)(Ω) Across R1 Across R2

(µV/˚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 50 µA

LM185-1.2/LM285-1.2/LM385-1.2

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Typical Applications (Continued)

Schematic Diagram

Centigrade Thermometer

DS005518-1

Calibration

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

2. Adjust V2 to 273.2 mV

†

IQfor 1.3V to 1.6V battery volt-

age=50 µA to 150 µA

DS005518-7

LM185-1.2/LM285-1.2/LM385-1.2

www.national.com7

Physical Dimensions inches (millimeters) unless otherwise noted

TO-46 Metal Can Package (H)

Order Number LM185H-1.2, LM185H-1.2/883, LM185BXH-1.2, LM185BYH-1.2, LM285H-1.2, or LM285BXH-1.2

NS Package Number H02A

SOT-23 Package (M3)

Order Number LM385M3-1.2

NS Package Number MA03B

LM185-1.2/LM285-1.2/LM385-1.2

www.national.com 8

Physical Dimensions inches (millimeters) unless otherwise noted (Continued)

Small Outline (SO-8) Package

Order Number LM285M-1.2, LM285BXM-1.2, LM285BYM-1.2

LM385M-1.2, LM385BM-1.2, LM385BXM-1.2, LM385BYM-1.2

NS Package Number M08A

TO-92 Plastic Package (Z)

Order Number LM285Z-1.2, LM285BXZ-1.2

LM285BYZ-1.2, LM385Z-1.2, LM385BZ-1.2

LM385BXZ-1.2 or LM385BYZ-1.2

NS Package Number Z03A

LM185-1.2/LM285-1.2/LM385-1.2

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Notes

LIFE SUPPORT POLICY

NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:

1. Life support devices or systems are devices or
systems which, (a) are intended for surgical implant
into the body, or (b) support or sustain life, and
whose failure to perform when properly used in
accordance with instructions for use provided in the
labeling, can be reasonably expected to result in a
significant injury to the user.

2. A critical component is any component of a life
support device or system whose failure to perform
can be reasonably expected to cause the failure of
the life support device or system, or to affect its
safety or effectiveness.

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LM185-1.2/LM285-1.2/LM385-1.2 Micropower Voltage Reference Diode

National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.