LM129/LM329

Precision Reference

General Description

The LM129 and LM329 family are precision multi-current

temperature-compensated 6.9V zener references with dy-

namic impedances a factor of 10 to 100 less than discrete di-

odes. Constructed in a single silicon chip, the LM129 uses

active circuitry to buffer the internal zener allowing the de-

vice to operate over a 0.5 mA to 15 mA range with virtually

no change in performance. The LM129 and LM329 are avail-

able with selected temperature coefficients of 0.001, 0.002,

0.005 and 0.01%/˚C. These references also have excellent

long term stability and low noise.

A new subsurface breakdown zener used in the LM129 gives

lower noise and better long-term stability than conventional

IC zeners. Further the zener and temperature compensating

transistor are made by a planar process so they are immune

to problems that plague ordinary zeners. For example, there

is virtually no voltage shift in zener voltage due to tempera-

ture cycling and the device is insensitive to stress on the

leads.

The LM129 can be used in place of conventional zeners with

improved performance. The low dynamic impedance simpli-

fies biasing and the wide operating current allows the re-

placement of many zener types.

The LM129 is packaged in a 2-lead TO-46 package and is

rated for operation over a −55˚C to +125˚C temperature

range. The LM329 for operation over 0˚C to 70˚C is available

in both a hermetic TO-46 package and a TO-92 epoxy pack-

age.

Features

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0.6 mA to 15 mA operating current

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0.6

Ω dynamic impedance at any current

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Available with temperature coefficients of 0.001%/˚C

n

7µV wideband noise

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5% initial tolerance

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0.002% long term stability

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Low cost

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Subsurface zener

Connection Diagrams

Metal Can Package (T0–46)

DS005714-6

Pin 2 is electrically connected to case

Bottom View

Order Number LM129AH, LM129AH/883, LM129BH,

LM129BH/883, LM129CH, LM329AH, LM329BH,

LM329CH or LM329DH

See NS Package H02A

Plastic Package (TO-92)

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Bottom View

Order Number LM329BZ,

LM329CZ or LM329DZ

See NS Package Z03A

March 2000

© 2000 National Semiconductor Corporation

DS005714

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