28V synchronous buck power converter has wide input range

The design uses a novel low-voltage technique that enables high-frequency switching with high gate drive. The controller runs at a constant 1.2MHz frequency that can be programmed using an external capacitor. The device’s 1.7A gate drive current is capable of driving large MOSFETs resulting in efficient 40A single phase converter designs.

The device supports an asynchronous start-up mode to keep the lower side MOSFET turned off until output is within regulation so that the external bus is not discharged. This is an ideal feature for applications with preset external voltage or pre-biased output voltage. Built-in cross conduction prevention circuitry prevents shoot-through minimizing dead time and losses.

“Datacom and server designs face increased power requirements in a limited space and call for a solution like the SC4612 to allow system designers to increase their port density while shrinking board size,” said Nejo Necar, Vice President of Marketing for Semtech’s Power Management Group. “The SC4612’s synchronous rectified buck topology results in 95% peak efficiency that enables industry leading compact on-board dc to dc converter designs with 93W/sq. inch of power density.”

SC4612 features programmable current limit with built-in hiccup mode and over temperature protection. It is available in either an MLPD-12 or a SOIC-14 package in lead-free versions that meet RoHS/WEEE specifications.

The SC4612 is available immediately in production quantities. Order code for the MPLD-12 packaged device is SC4612MLTRT and is priced at $0.80 each in 1,000-pc quantities. Order code for the SOIC-14 packaged device is SC4612STRT and is priced at $0.93 each in 1,000-pc quantities. Semtech offers comprehensive design assistance, including field- and factory-based support.