The CS8121 is a 5V, 1A precision linear regulator with two microprocessor compatible control functions and protection circuitry included on chip. The composite NPN-PNP output pass transistor assures a lower dropout voltage (1.2V @ 1A) without requiring excessive supply current (4mA). The CS8121s two logic control functions make this regulator well suited to applications requiring microprocessorbased control at the board or module level. ENABLE controls the output stage. A high voltage (>2.9V) on the ENABLE lead turns off the regulators pass transistor and sends the IC into Sleep mode where it draws only