LM185-1.2/LM285-1.2/LM385-1.2 Micropower Voltage Reference Diode
January 30, 2008
LM185-1.2/LM285-1.2/LM385-1.2
Micropower Voltage Reference Diode
General Description
The LM185-1.2/LM285-1.2/LM385-1.2 are micropower 2-ter-
minal band-gap voltage regulator diodes. Operating over a
10μA to 20mA current range, they feature exceptionally 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 transistors and re-
sistors, low noise and good long term stability result.
Careful design of the LM185-1.2 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 LM185-1.2 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.
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 carrier package.
Features
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±1% and 2% initial tolerance
Operating current of 10μA to 20mA
1Ω
dynamic impedance
Low temperature coefficient
Low voltage reference—1.235V
2.5V device and adjustable device also available
LM185-2.5 series and LM185 series, respectively
Connection Diagrams
T0-92
Plastic Package (Z)
SOT23
551833
551810
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
SO Package
* 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 MF03A
TO-46
Metal Can Package (H)
551809
551806
Order Number LM285M-1.2,
LM285BXM-1.2, LM285BYM-1.2
LM385M-1.2, LM385BM-1.2
LM385BXM-1.2 or LM385BYM-1.2
See NS Package Number M08A
Bottom View
Order Number LM185H-1.2, LM185H-1.2/883,
LM185BXH-1.2, LM185BYH-1.2
LM285H-1.2 or LM285BXH-1.2
See NS Package Number H02A
© 2008 National Semiconductor Corporation
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