Cherry Semiconductor Corp. (East Greenwich, RI) introduced the new CS-51311 and CS-51312 synchronous buck controller ICs. The CS-51311 is intended for use as a CPU controller, providing a small footprint device to power and protect the processor's core logic. The CS-51312 is designed specifically to meet the power management needs of high-end and server computer systems having only a 12V supply voltage.A single pin on the CS-51311's package handles four different functions: soft start, an output enable to control the regulator outputs, error amplifier output and hiccup-mode overcurrent timing. Other features on the device include a power good output to monitor the regulator output, hiccup-mode overcurrent protection, a Vcc monitor for undervoltage lockout, and overvoltage protection. The CS-51312 is claimed to offer the lowest component count and smallest footprint power supply solution of any switching regulator designed for a 12V only system. Interal control features include power good output, hiccup-mode overcurrent protection, a Vcc monitor for undervoltage lockout, overvoltage protection, soft start, and an output enable to control the regulator outputs. Both ICs are synchronous dual-NFET buck regulators that drive a pair of external power NFETs, which in turn supply current and voltage to the motherboard's core logic. The devices operate from a single supply over a voltage range of 8.4V to 14V (12V nominal). An on-chip 5-bit DAC provides 1 percent tolerance to program the output voltage of the power supply. The voltage is programmable within two ranges: 2.125V to 3.525V in 100mV steps and 1.325V to 2.075V in 50mV steps. Available in a plastic 14-lead SO narrow package, the CS-51311 is priced at $1.37 each in quantities of 10,000. The CS-51312 is packaged in a plastic 16-lead SO narrow package, and is priced at $1.58 each in quantities of 10,000.