LM2940/LM2940C,pdf datasheet (

The LM2940/LM2940C positive voltage regulator features the
ability to source 1A of output current with a dropout voltage of
typically 0.5V and a maximum of 1V over the entire temperature
range. Furthermore, a quiescent current reduction circuit
has been included which reduces the ground current
when the differential between the input voltage and the output
voltage exceeds approximately 3V. The quiescent current
with 1A of output current and an input-output differential of 5V
is therefore only 30 mA. Higher quiescent currents only exist
when the regulator is in the dropout mode (VIN − VOUT ≤ 3V).
Designed also for vehicular applications, the LM2940/
LM2940C and all regulated circuitry are protected from reverse
battery installations or 2-battery jumps. During line
transients, such as load dump when the input voltage can
momentarily exceed the specified maximum operating volt