LM2991
LM2991 is Negative Low Dropout Adjustable Regulator manufactured by National Semiconductor.
- Part of the LM2 comparator family.
- Part of the LM2 comparator family.
Description
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 temperature 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 temperature range. The quiescent current is typically 1 m A 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 m A (typical) when the regulator is in the dropout mode (VOUT
- VIN ≤ 3V). The LM2991 is short-circuit proof, and thermal shutdown includes 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 available.
Features 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 patible ON/OFF switch n Functional plement to the LM2941 series
Applications n Post switcher regulator n Local, on-card, regulation n Battery operated equipment
Typical Application
DS011260-1
VOUT = VREF (1 + R2/R1)
- Required if the regulator is located further than 6 inches from the power supply filter capacitors. A 1 µF solid tantalum or a 10 µF aluminum electrolytic capacitor is remended.
- - Required for stability. Must be at least a 10 µF aluminum electrolytic or a 1 µF solid tantalum to maintain stability. May be increased without bound to maintain...
