LM112/LM212/LM312 Operational Amplifiers
General Description
The LM112 series are micropower operational amplifiers
with very low offset-voltage and input-current errorsDat
least a factor of ten better than FET amplifiers over a
b55§C to a125§C temperature range. Similar to the LM108
series, that also use supergain transistors, they differ in that
they include internal frequency compensation and have provisions
for offset adjustment with a single potentiometer.
These amplifiers will operate on supply voltages of g2V to
g20V, drawing a quiescent current of only 300 mA. Performance
is not appreciably affected over this range of voltages,
so operation from unregulated power sources is easily
accomplished. They can also be run from a single supply
like the 5V used for digital circuits.
The LM112 series are the first IC amplifiers to improve reliability
by including overvoltage protection for the MOS compensation
capacitor. Without this feature, IC's have been
known to suffer catastrophic failure caused by short-duration
overvoltage spikes on the supplies. Unlike other internally-
compensated IC amplifiers, it is possible to overcompensate
with an external capacitor to increase stability margin.
The LM212 is identical to the LM112, except that the LM212
has its performance guaranteed over a b25§C to a85§C
temperature range instead of b55§C to a125§C. The
LM312 is guaranteed over a 0§C to a70§C temperature
range.
Features
Y Maximum input bias current of 3 nA over temperature
Y Offset current less than 400 pA over temperature
Y Low noise
Y Guaranteed drift specifications