LM2937-2.5, LM2937-3.3 400mA and 500mA Voltage Regulators
February 1998
LM2937-2.5, LM2937-3.3
400mA and 500mA Voltage Regulators
General Description
The LM2937-2.5 and LM2937-3.3 are positive voltage regu-
lators capable of supplying up to 500 mA of load current.
Both regulators are ideal for converting a common 5V logic
supply, or higher input supply voltage, to the lower 2.5V and
3.3V supplies to power VLSI ASIC’s and microcontrollers.
Special circuitry has been incorporated to minimize the qui-
escent current to typically only 10 mA with a full 500 mA load
current when the input to output voltage differential is greater
than 5V.
The LM2937 requires an output bypass capacitor for stabil-
ity. As with most regulators utilizing a PNP pass transistor,
the ESR of this capacitor remains a critical design param-
eter, but the LM2937-2.5 and LM2937-3.3 include special
compensation circuitry that relaxes ESR requirements. The
LM2937 is stable for all ESR ratings less than 5Ω. This al-
lows the use of low ESR chip capacitors.
The regulators are also suited for automotive applications,
with built in protection from reverse battery connections,
two-battery jumps and up to +60V/−50V load dump tran-
sients. 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 (400mA for
SOT-223 package)
n
Output trimmed for 5% tolerance under all operating
conditions
n
Wide output capacitor ESR range, 0.01Ω up to 5Ω
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
DS100113-24
Front View
Order Number LM2937ET-2.5, LM2937ET-3.3,
See NS Package Number T03B
DS100113-25
Front View
Order Number LM2937IMP-2.5, LM2937IMP-3.3,
See NS Package Number MA04A
TO-263 Surface-Mount Package
DS100113-27
Side View
DS100113-26
Top View
Order Number LM2937ES-2.5, LM2937ES-3.3,
See NS Package Number TS3B
© 1998 National Semiconductor Corporation
DS100113
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