Micrel, Inc. introduced its Model MIC22400 fully integrated 4A synchronous buck regulator for powering systems from 3.3V and 5V supply rails. With operating frequency programmable from 800 KHz to 4 MHz, it features built-in sequencing, tracking and ramp control, enabling all power-up sequencing and tracking protocols. Targeted at the communications, computing peripherals and high-end consumer markets, the regulator is suitable for servers/routers, HD DVD recorders, wireless base stations, FPGAs, DSPs and low voltage ASICs. The regulator features fully integrated 60 m? P-FET and 35 m? N-FET switches that deliver a 4A output current with an input voltage range of 2.6V to 5.5V. The device has an adjustable output voltage down to 0.7V, and it provides efficiencies up to 95 percent.