Series Low Dropout Regulators

General Description
The LM2931 positive voltage regulator features a very low
quiescent current of 1mA or less when supplying 10mA
loads. This unique characteristic and the extremely low
input-output differential required for proper regulation (0.2V
for output currents of 10mA) make the LM2931 the ideal
regulator for standby power systems. Applications include
memory standby circuits, CMOS and other low power processor
power supplies as well as systems demanding as
much as 100mA of output current.
Designed originally for automotive applications, the LM2931
and all regulated circuitry are protected from reverse battery
installations or 2 battery jumps. During line transients, such
as a load dump (60V) when the input voltage to the regulator
can momentarily exceed the specified maximum operating
voltage, the regulator will automatically shut down to protect
both internal circuits and the load. The LM2931 cannot be
harmed by temporary mirror-image insertion. Familiar regulator
features such as short circuit and thermal overload
protection are also provided.
The LM2931 family includes a fixed 5V output (±3.8% tolerance
for A grade) or an adjustable output with ON/OFF pin.
Both versions are available in a TO-220 power package,
TO-263 surface mount package, and an 8-lead surface
mount package. The fixed output version is also available in
the TO-92 plastic and 6-Bump micro SMD packages.

Features
n Very low quiescent current
n Output current in excess of 100 mA
n Input-output differential less than 0.6V
n Reverse battery protection
n 60V load dump protection
n −50V reverse transient protection
n Short circuit protection
n Internal thermal overload protection
n Mirror-image insertion protection
n Available in TO-220, TO-92, TO-263, SO-8 or 6-Bump
micro SMD packages
n Available as adjustable with TTL compatible switch
n See AN-1112 for micro SMD considerations