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 ¡Ü 3V).
Output voltage accuracy is guaranteed to ¡À5% 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