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Semtech has launched two buck regulators suitable for office automation, networking and communications equipment, set-top boxes, portable products, power supply modules and other embedded products.

The SC173 and SC174 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.

The new POL regulators help designers meet demanding ‘green’ power requirements by efficiently managing both standby- and full-current demands.

The SC173 and SC174 converters use the company’s Ecospeed architecture to achieve the best of conventional current mode, voltage mode and constant on-time control topologies, with minimal trade-offs.

This architecture enables ultra-fast transient response and high efficiency across light- to full-power loads, while eliminating the need for external compensation components, providing a space-saving and cost-effective power management solution, according to Semtech.

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 per cent accuracy and predictable electromagnetic interference (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 optimise their power supplies to maximise either the conversion efficiency or the solution size.

They also incorporate the company’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 said to be increasingly important to comply with emerging ‘green’ initiatives.

However, most electronic products also require a 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 for low-power standby requirements, thereby reducing the switching losses associated with the power FET gate charge.

This results in up to 95 per cent 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.

Upsave also ensures that the device switching frequency stays above the 25kHz threshold, thus eliminating audible resonance.

The Ecospeed architecture allows the SC173 and the SC174 to work with ceramic input and output capacitors.

This, combined with the fact there are no external compensation components, optimises BOM costs and reduces customers’ time to design.

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

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

The SC173 and the SC174 are available immediately in production quantities and are priced at USD1.80 (GBP1.20) each for the SC173 and USD1.90 each for the SC174 in 3,000-piece lots.

Ordering codes are SC174MLTRT and SC173MLTRT.

Evaluation boards (SC174EVB and SC173EVB) are also available.

Semtech offers design assistance, including field- and factory-based support.

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