Buck regulators deliver increased power density

Vishay Intertechnology, Inc. has expanded its microBUCK line of synchronous buck regulators with a new family of 15 A, 25 A, and 40 A devices that offer input voltages from 4.5 V to 20 V. The Vishay Siliconix SiC45x family regulators offer PMBus 1.3 compliance for power system telemetry, simplifying the design of point of load (POL) converters in cloud computing, enterprise servers, and industrial computers. They also are used in a range of networking, telecom, and storage system applications.

Delivering increased power density and transient response compared to previous-generation devices, the SiC45x devices co-package high performance n-channel trench MOSFETs with a PWM controller in a compact thermally-enhanced 5 × 7 mm PowerPAK MLP34-57 package. The regulators offer low operating current in idle mode, enabling peak efficiency up to 98% and reducing power losses, said Vishay. Thanks to the high integration, these buck regulators require minimal external components for configuration and loop compensation.

The SiC45x buck regulators are internally compensated over the entire V_IN and V_OUT range of operation. Other key features include an adjustable output voltage from 0.3 V to 12 V, programmable switching frequencies from 300 kHz to 1.5 MHz, and three operating modes: forced continuous conduction, power save, or ultrasonic. Protection and monitoring features include output over- and undervoltage protection (OVP/UVP), overcurrent protection (OCP) in pulse-by-pulse mode, differential output remote sensing, and over temperature protection (OTP) with hysteresis.

SiC450x efficiency curve (Image: Vishay Intertechnology datasheet)

“The regulators’ constant on-time (COT) architecture delivers ultra-fast transient response with minimum output capacitance and tight ripple regulation over a broad load range,” said Vishay. “It also enables loop stability regardless of the type of output capacitor used.”

Samples and production quantities of the SiC45x family are available now, with lead times of 16 weeks. Pricing for U.S. delivery ranges from $2.40 for the 15 A SiC453 to $3.35 for the 40 A SiC450, in quantities of 1,000.