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 10A 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 refer-
ences with a tighter tolerance part.
The LM185 is rated for operation over a 55C to 125C tem-
perature range, while the LM285 is rated 40C to 85C and
the LM385 0C to 70C. 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
n
Adjustable from 1.24V to 5.30V
n
Operating current of 10A to 20mA
n
1% and 2% initial tolerance
n
1
dynamic impedance
n
Low temperature coefficient
Connection Diagrams
TO-92
Plastic Package
DS005250-9
Bottom View
TO-46
Metal Can Package
DS005250-1
Bottom View
SOIC Package
DS005250-10
Top View
20-Leadless Chip Carrier
DS005250-15
Top View
February 2000
LM185/LM285/LM385
Adjustable
Micropower
V
oltage
Reference
2000 National Semiconductor Corporation
DS005250
www.national.com