Switching Regulator Integrates Many Features

The S-8550/8551 Series CMOS, synchronous rectification step-down switching regulator integrates a reference voltage circuit, an oscillator, error amplifier, a phase compensation circuit, PWM controller, an under-voltage-lockout circuit, a current limit circuit, and a power MOSFET. Oscillation frequency is 1.2 MHz, allowing for the use of small external parts. Specifications include an input voltage range from 2V to 5.5V, an arbitrarily adjustable output voltage range settable via an external resistor, output current of 600 mA, reference voltage of 0.6V ±2.0%, and an efficiency of 92%. Other features include a 1-ms soft-start function, a maximum shutdown current of 1 µA, and current limiting. Pricing is $0.54 each/10,000. SEIKO INSTRUMENTS USA INC., Torrance, CA. (310) 517-7700.