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
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 55C to +125C while the LM299 is
rated for operation from 25C to +85C and the LM399 is
rated from 0C to +70C.
The LM3999 is packaged in a standard TO-92 package and
is rated from 0C to +70C
Features
n Guaranteed 0.0001%/C temperature coefficient
n Low dynamic impedance — 0.5
n Initial tolerance on breakdown voltage — 2%
n Sharp breakdown at 400 A
n Wide operating current — 500 A to 10 mA
n Wide supply range for temperature stabilizer
n Guaranteed low noise
n Low power for stabilization — 300 mW at 25C
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
A =
+25C (T
J = +86C)
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
LM199/LM299/LM399/LM3999
Precision
Reference
1999 National Semiconductor Corporation
DS005717
www.national.com