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January 30, 2008
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 refer-
ence 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 ana-
log 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 is rated for operation over a −55°C to 125°C tem-
perature 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 package, while the
LM285/LM385 are available in a low-cost TO-92 molded
package, as well as S.O.
Features
■
Adjustable from 1.24V to 5.30V
■
Operating current of 10μA to 20mA
■
1% and 2% initial tolerance
■
1Ω dynamic impedance
■
Low temperature coefficient
Connection Diagrams
TO-92
Plastic Package
525009
Bottom View
TO-46
Metal Can Package
525001
Bottom View
SOIC Package
525010
Top View
20-Leadless Chip Carrier
525015
Top View
© 2008 National Semiconductor Corporation 5250 www.national.com
LM185/LM285/LM385 Adjustable Micropower Voltage Reference
