LM2940.pdf part of Keithley LM2940 LM2940.pdf, Keithley 2001 ds LM2940.pdf text manual preview

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LM2940/LM2940C 1A Low Dropout Regulator
January 2007

LM2940/LM2940C
1A Low Dropout Regulator
age, the regulator will automatically shut down to protect both
General Description the internal circuits and the load. The LM2940/LM2940C can-
The LM2940/LM2940C positive voltage regulator features the not be harmed by temporary mirror-image insertion. Familiar
ability to source 1A of output current with a dropout voltage of regulator features such as short circuit and thermal overload
typically 0.5V and a maximum of 1V over the entire temper- protection are also provided.
ature range. Furthermore, a quiescent current reduction cir-
cuit has been included which reduces the ground current Features
when the differential between the input voltage and the output
voltage exceeds approximately 3V. The quiescent current Dropout voltage typically 0.5V @IO = 1A
with 1A of output current and an input-output differential of 5V Output current in excess of 1A
is therefore only 30 mA. Higher quiescent currents only exist Output voltage trimmed before assembly
when the regulator is in the dropout mode (VIN - VOUT 3V).
Reverse battery protection
Designed also for vehicular applications, the LM2940/
Internal short circuit current limit
LM2940C and all regulated circuitry are protected from re-
verse battery installations or 2-battery jumps. During line Mirror image insertion protection
transients, such as load dump when the input voltage can P+ Product Enhancement tested
momentarily exceed the specified maximum operating volt-

Typical Application

882203
*Required if regulator is located far from power supply filter.
**COUT must be at least 22 F to maintain stability. May be increased without bound to maintain regulation during transients. Locate as close as possible to
the regulator. This capacitor must be rated over the same operating temperature range as the regulator and the ESR is critical; see curve.

Ordering Information
Temp Output Voltage
Package
Range 5.0 8.0 9.0 10 12 15
LM2940CT-5.0