NSC LM285MX-1.2, LM285BXZ-1.2, LM285BXMX-1.2, LM285BXM-1.2, LM285BYMX-1.2 Datasheet

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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