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January 30, 2008
LM185-2.5/LM285-2.5/LM385-2.5
Micropower Voltage Reference Diode
General Description
The LM185-2.5/LM285-2.5/LM385-2.5 are micropower 2-ter-
minal band-gap voltage regulator diodes. Operating over a 20
μA to 20 mA current range, they feature exceptionally low dy-
namic impedance and good temperature stability. On-chip
trimming is used to provide tight voltage tolerance. Since the
LM-185-2.5 band-gap reference uses only transistors and re-
sistors, low noise and good long term stability result.
Careful design of the LM185-2.5 has made the device excep-
tionally tolerant of capacitive loading, making it easy to use in
almost any reference application. The wide dynamic operat-
ing range allows its use with widely varying supplies with
excellent regulation.
The extremely low power drain of the LM185-2.5 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. For applications re-
quiring 1.2V see LM185-1.2.
The LM185-2.5 is rated for operation over a −55°C to 125°C
temperature range while the LM285-2.5 is rated −40°C to 85°
C and the LM385-2.5 0°C to 70°C. The LM185-2.5/LM285-2.5
are available in a hermetic TO-46 package and the
LM285-2.5/LM385-2.5 are also available in a low-cost TO-92
molded package, as well as S.O. and SOT-23. The
LM185-2.5 is also available in a hermetic leadless chip carrier
package.
Features
■
±20 mV (±0.8%) max. initial tolerance (A grade)
■
Operating current of 20 μA to 20 mA
■
0.6Ω dynamic impedance (A grade)
■
Low temperature coefficient
■
Low voltage reference—2.5V
■
1.2V device and adjustable device also available—
LM185-1.2 series and LM185 series, respectively
Connection Diagrams
TO-92
Plastic Package
551908
Bottom View
Order Number LM285Z-2.5,
LM285BXZ-2.5, LM285BYZ-2.5
LM385Z-2.5, LM385AXZ-2.5
LM385AYZ-2.5, LM385BZ-2.5,
LM385BXZ-2.5 or LM385BYZ-2.5
See NS Package Number Z03A
SO Package
551911
Order Number LM285M-2.5,
LM285BXM-2.5, LM285BYM-2.5
LM385M-2.5, LM385BM-2.5
LM385BXM-2.5 or LM385BYM-2.5
See NS Package Number M08A
SOT-23
551929
* Pin 3 is attached to the Die Attach Pad (DAP) and should be connected to Pin 2 or left floating.
Order Number LM385M3-2.5
See NS Package Number MA03B
© 2008 National Semiconductor Corporation 5519 www.national.com
LM185-2.5/LM285-2.5/LM385-2.5 Micropower Voltage Reference Diode
