March 2000
LM129/LM329
Precision Reference
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.
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.
Features
n 0.6 mA to 15 mA operating current
n 0.6Ω dynamic impedance at any current
n Available with temperature coefficients of 0.001%/˚C
n 7µV wideband 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.
n 5% initial tolerance
n 0.002% long term stability
n Low cost
n Subsurface zener
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.
Connection Diagrams
Metal Can Package (T0–46)
Plastic Package (TO-92)
DS005714-4
DS005714-6
Bottom View
Pin 2 is electrically connected to case
Order Number LM329BZ,
LM329CZ or LM329DZ
See NS Package Z03A
Bottom View
Order Number LM129AH, LM129AH/883, LM129BH,
LM129BH/883, LM129CH, LM329AH, LM329BH,
LM329CH or LM329DH
See NS Package H02A
© 2000 National Semiconductor Corporation
DS005714
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