January 2000
LM185-1.2/LM285-1.2/LM385-1.2
Micropower Voltage Reference Diode
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 car-
rier package.
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 µA to 20 mA current range, they feature exception-
ally 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 transis-
tors and resistors, low noise and good long term stability re-
sult.
Features
Careful design of the LM185-1.2 has made the device ex-
ceptionally 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.
±
±
%
4 mV ( 0.3 ) max. initial tolerance (A grade)
n
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
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.
Connection Diagrams
SOT23
T0-92
Plastic Package (Z)
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
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
© 2000 National Semiconductor Corporation
DS005518
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