The AAT3218 MicroPower™ low dropout linear regulator is ideally suited for portable applications where very fast transient response, extended battery life, and small size are critical. The AAT3218 has been specifically designed for high-speed turn-on and turnoff performance, fast transient response, and good power supply ripple rejection (PSRR), and is reasonably low noise, making it ideal for powering sensitive circuits with fast switching requirements. Other features include low quiescent current, typically 70μA, and low dropout voltage, typically less than 200mV at the maximum output current level of 150mA. The device is output short-circuit protected and has a thermal shutdown circuit for additional protection under extreme operating conditions. The AAT3218 also features a low-power shutdown mode for extended battery life. A reference bypass pin has been provided to improve PSRR performance and output noise, by connecting a small external capacitor from device reference output to ground. The AAT3218 is available in a Pb-free, space-saving 5-pin SOT23 or 8-pin SC70JW package in 16 factory-programmed voltages: 1.2V, 2.3V, 2.8V, 2.85V, or 3.5V.