The LM2937 is a
positive voltage regulator capable of supplying 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 0.5 V (1-V ensured maximum over the full operating temperature range). Special circuitry
has been incorporated to minimize the quiescent current to typically only 10 mA with a full 500-mA
load current when the input to output voltage differential is greater than 3 V.
The LM2937 requires
an output bypass capacitor for stability. As with most low dropout regulators, the ESR of this
capacitor remains a critical design parameter, but the LM2937 includes special compensation circuitry that relaxes ESR
requirements. The device is stable for all ESR below 3 Ω. 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
connections, two-battery jumps, and up to 60-V/−50-V load dump transients. Familiar regulator
features such as short circuit and thermal shutdown protection are also built in.
