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LM2991 Negative Low Dropout Adjustable Regulator
September 2000
LM2991
Negative Low Dropout Adjustable Regulator
General Description Features
The LM2991 is a low dropout adjustable negative regulator n Output voltage adjustable from -3V to -24V, typically
with a output voltage range between -3V to -24V. The -2V to -25V
LM2991 provides up to 1A of load current and features a On n Output current in excess of 1A
/Off pin for remote shutdown capability. n Dropout voltage typically 0.6V at 1A load
The LM2991 uses new circuit design techniques to provide a n Low quiescent current
low dropout voltage, low quiescent current and low tempera- n Internal short circuit current limit
ture coefficient precision reference. The dropout voltage at n Internal thermal shutdown with hysteresis
1A load current is typically 0.6V and a guaranteed n TTL, CMOS compatible ON/OFF switch
worst-case maximum of 1V over the entire operating tem-
n Functional complement to the LM2941 series
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 Applications
supply limits the quiescent current to only 9 mA (typical) n Post switcher regulator
when the regulator is in the dropout mode (VOUT - VIN 3V). n Local, on-card, regulation
The LM2991 is short-circuit proof, and thermal shutdown in- n Battery operated equipment
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