Vishay — SiC45x microBUCK® Synchronous Buck Regulators

The Vishay portfolio of microBUCK® synchronous buck regulators includes a family of 15 A, 25 A, and 40 A devices in a thermally enhanced 5 mm x 7 mm PowerPAK® package. The SiC45x devices operate from an input voltage range of 4.5 V to 20 V, and supply an output voltage in the range 0.3 V to 12 V.

With a compact footprint, the 15 A SiC453, 25 A SiC451, and 40 A SiC450 provide higher power density than the previous generation of devices. The regulators’ high power density is the result of co-packaging high-performance N-channel trench MOSFETs with a PWM controller in a single device. Simplifying the design of high-performance point of load converters, the integrated devices require few external components for configuration and loop compensation.

The constant on-time architecture of the SiC45x also provides a very fast response to transient voltages, with minimum output capacitance and tight ripple regulation over a broad range of loads. The regulators maintain good loop stability regardless of the type of output capacitor used.

These Vishay buck regulators include a PMBus 1.3-compliant interface, supporting the implementation of power system telemetry in complex installations such as data centers and telecoms central offices.

The regulators automatically choose the correct internal compensation values based on the operating condition during the start-up sequence. At light loads, when the inductor current crosses zero, the control scheme turns off the low-side MOSFET to deploy a diode emulation mode with frequency foldback.

In ultrasonic mode, the frequency does not go below 25 kHz, keeping the switching frequency above the audible range, which is a benefit for noise-sensitive applications.