LM199/LM299/LM399 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 0.5Ω and
allows 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
ordinary monolithic zeners. The package is supplied with a
thermal shield to minimize heater power and improve temperature
regulation.
The LM199 series references are exceptionally easy to use
and free of the problems that are often experienced with
ordinary 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
applications are analog to digital converters, calibration standards,
precision voltage or current sources or precision
power supplies. Further in many cases the LM199 can replace
references in existing equipment with a minimum of
wiring changes.
The LM199 series devices are packaged in a standard hermetic
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.
Features
n Guaranteed 0.0001%/°C temperature coefficient
n Low dynamic impedance — 0.5Ω
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 Proven reliability, low-stress packaging in TO-46
integrated-circuit hermetic package, for low hysteresis
after thermal cycling. 33 million hours MTBF at TA =
+25°C (TJ = +86°C)