LT1964.pdf

General Description
The LM2990 is a three-terminal, low dropout, 1 ampere
negative voltage regulator available with fixed output volt-
ages of −5, −5.2, −12, and −15V.
The LM2990 uses new circuit design techniques to provide
ow dropout and low quiescent current. The dropout voltage
at 1A load current is typically 0.6V and a guaranteed
worst-case maximum of 1V over the entire operating tem-
perature range. The quiescent current is typically 1 mA with
1A load current and an input-output voltage differential
greater than 3V. A unique circuit design of the internal bias
supply limits the quiescent current to only 9 mA (typical)
when the regulator is in the dropout mode (VOUT −VIN ≤ 3V).
Output voltage accuracy is guaranteed to ±5% over load,
and temperature extremes.
The LM2990 is short-circuit proof, and thermal shutdown in-
cludes hysteresis to enhance the reliability of the device
when overloaded for an extended period of time. The
LM2990 is available in a 3-lead TO-220 package and is rated
for operation over the automotive temperature range of
−40˚C to +125˚C.
Features
n 5% output accuracy over entire operating range
n Output current in excess of 1A
n Dropout voltage typically 0.6V at 1A load
n Low quiescent current
n Internal short circuit current limit
n Internal thermal shutdown with hysteresis
n Functional complement to the LM2940 series
Applications
n Post switcher regulator
n Local, on-card, regulation
n Battery operated equipment