Semtech SC171/SC172 buck regulators

Semtech has launched the SC171 and SC172 buck regulators. These 1 and 2 A output devices are the latest additions to the company’s EcoSpeed DC-DC converter platform, which includes a broad selection of output current capabilities ranging from 1 to 30 A.

The converters help designers meet emerging green power requirements by efficiently managing both standby and full current demands in networking and office automation equipment, set top boxes, portable products, power supply modules and other embedded products, including dynamic point-of-load applications.

The devices incorporate adaptive on-time architecture for green power requirements by efficiently managing both stand-by and full current demands. The AOT architecture uses a control loop that eliminates the need for loop compensation components and enables the use of ceramic input and output capacitors.

Both regulators are programmable from 200 kHz to 1 MHz, enabling designers to optimise their power supply to maximise either the conversion efficiency or the solution size. They also feature SmartDrive, which is a two-step, high-side FET turn-on technology designed to reduce EMI in noise-sensitive applications.

Additionally, both devices provide high efficiency across the entire load range, with up to 95% peak operating efficiency and selectable, ultrasonic power save, which lowers the switching frequency to cater to light-load requirements during stand-by.

When the load changes from stand-by to full load, the cycle-by-cycle response of the EcoSpeed architecture quickly exits PSAVE mode to provide very fast wake-up recovery time. This enables power designers to meet ‘green’ regulations, while maintaining fast user performance. To eliminate audible noise during stand-by, the ultrasonic PSAVE configuration maintains switching frequencies above the 25 kHz audible threshold.

The regulators incorporate soft start to reduce inrush and minimise stress on the input power source, along with dedicated power-good and enable pins to simplify power supply design. Comprehensive fault protection features include cycle-by-cycle current limit and short circuit, over and under output voltage, and over-temperature protection.