International Rectifier’s (IR) IR3651 is a synchronous PWM controller; operating from a pair of IR’s DirectFET MOSFETs, it can achieve greater than 88% system efficiency at 48 VIN and 3.3 VOUT at 6 A without a heatsink or air flow. The IR3651 is designed to drive a pair of external n-channel MOSFETs up to 25 A.
It has an input-voltage range from 12 V to 75 V. The minimum output voltage is 1.25 V, and the maximum output voltage is 0.7 x VIN.
The device has a programmable switching frequency from 100 kHz to 400 kHz. The device also offers synchronization, which allows simplified system-level EMI-filter design.
The controller also includes a 150-V half-bridge driver that allows for design flexibility. For instance, the device may be used in low-power (less than 60 W) nonisolated dc-dc converters for network equipment as well as high-power (greater than 200 W) pre-regulator stages in regulated isolated converters.
The IR3651 is available now. Pricing is $2.00 each in 10,000-unit quantities.