Low dropout regulators (LDOs) are a simple and cost-effective way to get a regulated output voltage from higher input voltage. LDOs provide great simplicity for the system design as they are widely used in broad applications due to no switching noise and small size.

The AP7381 series is a positive voltage regulator IC. The AP7381 has features of wide input voltage range, high accuracy, low dropout voltage, current limit and ultra-low quiescent current which make it ideal for use in various USB and portable devices. The IC consists of a voltage reference, an error amplifier, a resistor network for setting output voltage, a current limit circuit for current protection, and a chip enable circuit. The AP7381 has 3.3V, 5V fixed voltage version. The AP7381 is available in space-saving SOT89 (Option 2) and TO92 (Ammo Packing) packages.

Wide Input Voltage Range: Up to 40V
Low Dropout Voltage: VDROP = 1000mV@IOUT = 100mA @ Vout=3.3V
Low Ground Current
High Output Voltage Accuracy
Compatible with Low ESR Ceramic Capacitor
Excellent Line/Load Regulation
Thermal Shutdown Function
Short Current Protection Function
Applications
E-Meter
Battery-powered Equipment
Laptop, Palmtops, Notebook Computers
Portable Information Appliances