Semtech EcoSpeed DC-DC converters provide ultra-fast transient response and high efficiency across full load range

CAMARILLO, USA: Semtech Corp., a leading supplier of analog and mixed-signal semiconductors, has launched the SC173 and SC174 buck regulators.

These devices are the latest in the company’s EcoSpeed DC-DC converter platform, which incorporates Semtech’s advanced, patented adaptive on-time architecture to achieve best-in-class performance in next-generation dynamic point-of-load (POL) applications.

They are ideal for office automation, networking and communications equipment; set-top boxes; portable products; power supply modules; and other embedded products. The new SC173 and SC174 POL regulators help designers meet today’s demanding green power requirements by efficiently managing both standby and full current demands.

The SC173 and SC174 converters use Semtech’s EcoSpeed architecture to achieve the best of conventional current mode, voltage mode and constant on-time control topologies, with minimal tradeoffs. This architecture enables ultra-fast transient response and very high efficiency across light to full power loads, while eliminating the need for external compensation components, providing a simple, space-saving and cost-effective power management solution.

The EcoSpeed architecture uses an advanced control loop to dynamically adjust the on-time based on input voltage and output voltage. This approach enables 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 allowing designers to optimize their power supply to maximize either the conversion efficiency or the solution size. They also 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.

Very low power during standby mode is increasingly important to comply with emerging “green” initiatives. However, most electronic products also require fast “wake-up” capability, which demands fast recovery from low-power standby to full-power steady state mode.

The SC173 and SC174 EcoSpeed converters solve this challenge with 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. This results in up to 95% peak standby efficiency.

Then, 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, providing design flexibility and reliability. This, combined with no external compensation components optimizes BOM costs and reduces customers’ time-to-design.

The SC173 and SC174 offer output currents of 3A and 4A respectively and are packaged in a 10-pad, 3.0 x 3.0 x 1.0 mm, lead-free, halogen-free MLPD package for further space savings.

The SC173 and SC174 join Semtech’s existing family of higher voltage, higher current EcoSpeed DC-DC converters, providing the same adaptive on-time architecture benefits for lower voltage, lower current point-of-load applications.

Additional devices in the family include ultrasonic power-save devices: SC414 (6A), SC417 (10A), SC418 (30A controller with low dropout regulator), SC419 (30A controller); as well as standard power-save devices: SC424 (6A) and SC427 (10A).

The SC173 and SC174 are available immediately in production quantities and are priced at $1.80 for the SC173 and $1.90 for the SC174 each in 3,000-piece lots. Ordering codes are SC174MLTRT and SC173MLTRT. Evaluation boards (SC174EVB and SC173EVB) are also available. Semtech offers comprehensive design assistance, including field- and factory-based support.