LM185/LM285/LM385

Adjustable Micropower Voltage References

General Description

The LM185/LM285/LM385 are micropower 3-terminal ad-

justable band-gap voltage reference diodes. Operating from

1.24 to 5.3V and over a 10µA to 20mA current range, they

feature exceptionally low dynamic impedance and good tem-

perature stability. On-chip trimming is used to provide tight

voltage tolerance. Since the LM185 band-gap reference

uses only transistors and resistors, low noise and good

long-term stability result.

Careful design of the LM185 has made the device 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 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. Fur-

ther, the wide operating current allows it to replace older

references with a tighter tolerance part.

The LM185 is rated for operation over a −55˚C to 125˚C

temperature range, while the LM285 is rated −40˚C to 85˚C

and the LM385 0˚C to 70˚C. The LM185 is available in a

hermetic TO-46 package and a leadless chip carrier pack-

age, while the LM285/LM385 are available in a low-cost

TO-92 molded package, as well as S.O.

Features

n

Adjustable from 1.24V to 5.30V

n

Operating current of 10µA to 20mA

n

1% and 2% initial tolerance

n

1

Ω dynamic impedance

n

Low temperature coefficient

Connection Diagrams

TO-92

Plastic Package

TO-46

Metal Can Package

00525009

Bottom View

00525001

Bottom View

SOIC Package

20-Leadless Chip Carrier

00525010

Top View

00525015

Top View

February 2005

© 2005 National Semiconductor Corporation

DS005250

www.national.com