The LM129 and LM329 family are precision multi-current
temperature-compensated 6.9V zener references with dynamic impedances a factor of 10 to 100 less than discrete diodes. Constructed in a single silicon chip, the LM129 uses
active circuitry to buffer the internal zener allowing the device to operate over a 0.5 mA to 15 mA range with virtually
no change in performance. The LM129 and LM329 are available 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.
Anewsubsurfacebreakdownzener 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 temperature 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 simplifies biasing and the wide operating current allows the replacement of many zener types.
Connection Diagrams
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 package.
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
n 5% initial tolerance
n 0.002% long term stability
n Low cost
n Subsurface zener
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
(Note 3)
Reverse Breakdown Current30 mA
Forward Current2 mA
Operating Temperature Range
LM129−55˚C to +125˚C
LM3290˚C to +70˚C
Storage Temperature Range−55˚C to +150˚C
Soldering Information
TO-92 package: 10 sec.260˚C
TO-46 package: 10 sec.300˚C
Electrical Characteristics (Note 2)
LM129A, B, CLM329A, B, C, D
ParameterConditionsUnits
MinTypMaxMinTypMax
Reverse Breakdown VoltageT
Reverse Breakdown ChangeT
with Current (Note 4)0.6 mA ≤ I
Reverse Dynamic ImpedanceT
(Note 4)
RMS NoiseT
Long Term StabilityT
(1000 hours)I
Temperature CoefficientI
LM129A, LM329A610610ppm/˚C
LM129B, LM329B15201520ppm/˚C
LM129C, LM329C30503050ppm/˚C
LM329D50100ppm/˚C
Change In Reverse Breakdown1 mA ≤ I
Temperature Coefficient
Reverse Breakdown Change1 mA ≤ I
with Current
Reverse Dynamic Impedance1 mA ≤ I
Note 1: “Absolute Maximum Ratings” indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
functional, but do not guarantee specific performance limits.
Note 2: These specifications apply for −55˚C ≤ T
temperature for an LM129 is 150˚C and LM329 is 100˚C. For operating at elevated temperature, devices in TO-46 package must be derated based on a thermal resistance of 440˚C/W junction to ambient or 80˚C/W junction to case. For the TO-92 package, the derating is based on 180˚C/W junction to ambient with 0.4" leads
from a PC board and 160˚C/W junction to ambient with 0.125" lead length to a PC board.
Note 3: Refer to RETS129H for LM129 family military specifications.
Note 4: These changes are tested on a pulsed basis with a low duty-cycle. For changes versus temperature, compute in terms of tempco.
= 25˚C,
A
0.6 mA ≤ I
= 25˚C,
A
= 25˚C, IR= 1 mA0.610.82Ω
A
= 25˚C,
A
≤ 15 mA6.76.97.26.66.97.25V
R
≤ 15 mA914920mV
R
10 Hz ≤ F ≤ 10 kHz7207100µV
= 45˚C±0.1˚C,
A
=1mA±0.3%2020ppm
R
=1mA
R
≤ 15 mA11ppm/˚C
R
≤ 15 mA1212mV
R
≤ 15 mA0.81Ω
R
≤ +125˚C for the LM129 and 0˚C ≤ TA≤ +70˚C for the LM329 unless otherwise specified. The maximum junction
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can be reasonably expected to cause the failure of
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