GENERAL DESCRIPTION
The L431L is a three-terminal adjustable shunt regulator utilizing an accurate 1.24V band gap reference. The output voltage can be set to any value between 1.24V (VREF) to 18V with two external resistors as shown in the typical application circuit. The device exhibit a wide operating current range of 0.2 to 100 mA with a typical dynamic impedance of 0.25Ω. Active output circuitry provides a very sharp turn-on characteristic, making the L431L excellent replacements for low-voltage zener diodes in many applications, including on-board regulation and adjustable power supplies.
When used with an opto-coupler, the L431L is ideal voltage reference in isolated feedback circuits for 3.3V switching-mode power supplies. The L431L shunt regulator is available in two voltage tolerances (0.5% & 1.0%) and three package options (TO-92, SOT-23-3 and SO-8).

FEATURES
● Internal amplifier with 100 mA capability
● Programmable output voltage to 18V
● 0.25Ω typical output impedance
● Pin to pin compatible with TLV431A, TS431, SC431L & AS432
● Trimmed bandgap design 0.5% & 1.0% with three package options
● Low output noise

APPLICATIONS
● Linear regulator controller
● Precision voltage reference
● Switching power supplies
● Battery operating equipment
● Instrumentation
● PCs, Computer disk drives