EcoSpeed DC-DC converters provide 'ultra-fast' transient response

Semtech, a supplier of analogue and mixed signal semiconductors has announced the launch of its SC173 and SC174 buck regulators.

These devices are the latest in the company's EcoSpeed DC-DC converter platform, which incorporates the company's patented adaptive on-time architecture for next generation dynamic point-of-load (POL) applications. According to Semtech, they are suitable for office automation, networking and communications equipment; set-top boxes; portable products; power supply modules; and other embedded products. The POL regulators are designed to meet today's green power requirements by efficiently managing both standby and full current demands. The SC173 and SC174 converters use Semtech's EcoSpeed architecture which is said to enable 'ultra-fast' transient response and very high efficiency across light to full power loads, while eliminating the need for external compensation components. The EcoSpeed architecture uses a control loop to adjust the on-time based on input voltage and output voltage. This approach is said to enable a pseudo-fixed frequency operation with +/-15% accuracy and very predictable emi - comparable to conventional voltage mode and current mode topologies, and better than constant on-time and hysteretic architectures where frequencies are unpredictable. The SC173 and SC174 EcoSpeed converters are programmable from 200kHz to 1MHz and incorporate Semtech's proprietary SmartDrive technology, which is a two-step, high-side FET turn-on technology designed to reduce emi in noise-sensitive applications. The EcoSpeed converters incorporate an ultrasonic power-save (UPSAVE) mode. UPSAVE lowers the switching frequency to cater to low power standby requirements, thereby by reducing the switching losses associated with the power FET gate charge. According to Semtech, this results in up to 95% peak standby efficiency. When the load changes from standby to steady state, the EcoSpeed technology cycle-by-cycle response quickly exits UPSAVE mode providing very fast power-up response time. Additionally, UPSAVE ensures that the device switching frequency stays above the 25kHz threshold, thereby eliminating audible resonance. The EcoSpeed architecture allows the SC173 and SC174 to work with ceramic input and output capacitors. The devices offer output currents of 3A and 4A respectively and are packaged in a 10pad, 3 x 3 x 1mm, lead free, halogen free MLPD package.