The LM140L series of three terminal positive regulators is available with several fixed
output voltages making them useful in a wide range of applications. The LM140LA is an improved
version of the LM78LXX series with a tighter output voltage tolerance (specified over the full
military temperature range), higher ripple rejection, better regulation and lower quiescent
current. The LM140LA regulators have ±2% VOUT specification, 0.04%/V line
regulation, and 0.01%/mA load regulation. When used as a zener diode/resistor combination
replacement, the LM140LA usually results in an effective output impedance improvement of two orders
of magnitude, and lower quiescent current. These regulators can provide local on card regulation,
eliminating the distribution problems associated with single point regulation. The voltages
available allow the LM140LA to be used in logic systems, instrumentation, Hi-Fi, and other solid
state electronic equipment. Although designed primarily as fixed voltage regulators, these devices
can be used with external components to obtain adjustable voltages and currents.
The LM140LA/LM340LA are available in the low profile metal three lead TO (NDT) and the
LM340LA are also available in the plastic TO-92 (LP). With adequate heat sinking the regulator can
deliver 100 mA output current. Current limiting is included to limit the peak output current to a
safe value. Safe area protection for the output transistor is provided to limit internal power
dissipation. If internal power dissipation becomes too high for the heat sinking provided, the
thermal shut-down circuit takes over, preventing the IC from overheating.
For applications requiring other voltages, see LM117L Data Sheet.
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