LM2937 500 mA Low Dropout Regulator
March 2000
LM2937
500 mA Low Dropout Regulator
General Description
The LM2937 is a positive voltage regulator capable of sup-
plying up to 500 mA of load current. The use of a PNP power
transistor provides a low dropout voltage characteristic. With
a load current of 500 mA the minimum input to output voltage
differential required for the output to remain in regulation is
typically 0.5V (1V guaranteed maximum over the full operat-
ing temperature range). Special circuitry has been incorpo-
rated to minimize the quiescent current to typically only
10 mA with a full 500 mA load current when the input to out-
put voltage differential is greater than 3V.
The LM2937 requires an output bypass capacitor for stabil-
ity. As with most low dropout regulators, the ESR of this ca-
pacitor remains a critical design parameter, but the LM2937
includes special compensation circuitry that relaxes ESR re-
quirements. The LM2937 is stable for all ESR below 3Ω. This
allows the use of low ESR chip capacitors.
Ideally suited for automotive applications, the LM2937 will
protect itself and any load circuitry from reverse battery con-
nections, two-battery jumps and up to +60V/−50V load dump
transients. Familiar regulator features such as short circuit
and thermal shutdown protection are also built in.
Features
n
Fully specified for operation over −40˚C to +125˚C
n
Output current in excess of 500 mA
n
Output trimmed for 5% tolerance under all operating
conditions
n
Typical dropout voltage of 0.5V at full rated load current
n
Wide output capacitor ESR range, up to 3Ω
n
Internal short circuit and thermal overload protection
n
Reverse battery protection
n
60V input transient protection
n
Mirror image insertion protection
Connection Diagram and Ordering Information
TO-220 Plastic Package
SOT-223 Plastic Package
DS011280-2
Front View
Order Number LM2937ET-5.0, LM2937ET-8.0,
LM2937ET-10, LM2937ET-12 or LM2937ET-15
See NS Package Number T03B
DS011280-26
Front View
Order Number LM2937IMP-5.0,
LM2937IMP-8.0, LM2937IMP-10,
LM2937IMP-12 or LM2937IMP-15
See NS Package Number MP04A
TO-263 Surface-Mount Package
DS011280-6
Side View
DS011280-5
Top View
Order Number LM2937ES-5.0, LM2937ES-8.0,
LM2937ES-10, LM2937ES-12 or LM2937ES-15
See NS Package Number TS3B
© 2000 National Semiconductor Corporation
DS011280
www.national.com
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