LM2991 pdf

The LM2991 is a low dropout adjustable negative regulator
with a output voltage range between −3V to −24V. The
LM2991 provides up to 1A of load current and features a On
/Off pin for remote shutdown capability.
The LM2991 uses new circuit design techniques to provide a
low dropout voltage, low quiescent current and low tempera-
ture coefficient precision reference. 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
a 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).
The LM2991 is short-circuit proof, and thermal shutdown in-
cludes hysteresis to enhance the reliability of the device
when inadvertently overloaded for extended periods. The
LM2991 is available in 5-lead TO-220 and TO-263 packages
and is rated for operation over the automotive temperature
range of −40˚C to +125˚C. Mil-Aero versions are also avail-
able.
n Output voltage adjustable from −3V to −24V, typically
−2V to −25V
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 TTL, CMOS compatible ON/OFF switch
n Functional complement to the LM2941 series
Applications
n Post switcher regulator
n Local, on-card, regulation
n Battery operated equipment