LM199/LM299/LM399/LM3999

Precision Reference

General Description

The LM199 series are precision, temperature-stabilized

monolithic zeners offering temperature coefficients a factor

of ten better than high quality reference zeners. Constructed

on a single monolithic chip is a temperature stabilizer circuit

and an active reference zener. The active circuitry reduces

the dynamic impedance of the zener to about 0.5

Ω and al-

lows the zener to operate over 0.5 mA to 10 mA current

range with essentially no change in voltage or temperature

coefficient. Further, a new subsurface zener structure gives

low noise and excellent long term stability compared to ordi-

nary monolithic zeners. The package is supplied with a ther-

mal shield to minimize heater power and improve tempera-

ture regulation.

The LM199 series references are exceptionally easy to use

and free of the problems that are often experienced with or-

dinary zeners. There is virtually no hysteresis in reference

voltage with temperature cycling. Also, the LM199 is free of

voltage shifts due to stress on the leads. Finally, since the

unit is temperature stabilized, warm up time is fast.

The LM199 can be used in almost any application in place of

ordinary zeners with improved performance. Some ideal ap-

plications are analog to digital converters, calibration stan-

dards, precision voltage or current sources or precision

power supplies. Further in many cases the LM199 can re-

place references in existing equipment with a minimum of

wiring changes.

The LM199 series devices are packaged in a standard her-

metic TO-46 package inside a thermal shield. The LM199 is

rated for operation from −55˚C to +125˚C while the LM299 is

rated for operation from −25˚C to +85˚C and the LM399 is

rated from 0˚C to +70˚C.

The LM3999 is packaged in a standard TO-92 package and

is rated from 0˚C to +70˚C

Features

n Guaranteed 0.0001%/˚C temperature coefficient

n Low dynamic impedance — 0.5

Ω

n Initial tolerance on breakdown voltage — 2%

n Sharp breakdown at 400 µA

n Wide operating current — 500 µA to 10 mA

n Wide supply range for temperature stabilizer

n Guaranteed low noise

n Low power for stabilization — 300 mW at 25˚C

n Long term stability — 20 ppm

n Proven reliability, low-stress packaging in TO-46

integrated-circuit hermetic package, for low hysteresis

after thermal cycling. 33 million hours MTBF at T

+25˚C (T

n Certified long term stability available

n MIL-STD-883 compliant

Connection Diagrams

Metal Can Package (TO-46)

DS005717-14

Top View

LM199/LM299/LM399 (See Table on fourth page)

NS Package Number H04D

Plastic Package TO-92

DS005717-10

Bottom View

LM3999 (See Table on fourth page)

NS Package Number Z03A

May 1999

© 1999 National Semiconductor Corporation

DS005717

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