Semtech dc/dc converters deliver high efficiency across full load range

semtechecospeedCamarillo, Calif. — Semtech Corp. has launched the SC173 and SC174 buck regulators that tout an ultra-fast transient response and high efficiency across the full load range. 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.

These devices are well suited for set-top boxes, portable products, power supply modules, as well as office automation, networking and communications equipment and other embedded products.

The SC173 and SC174 POL regulators 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, said 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 percent 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 EcoSpeed converters are programmable from 200 kHz to 1 MHz 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.

To meet fast recovery requirements from low-power standby to full-power steady-state mode, the SC173 and SC174 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, said Semtech. This results in up to 95 percent peak standby efficiency.

When the load changes from standby to steady state, the EcoSpeed technology cycle-by-cycle response exits UPSAVE mode providing very fast power-up response time. UPSAVE ensures that the device switching frequency stays above the 25-kHz threshold, thereby eliminating audible resonance, said Semtech.

The EcoSpeed architecture allows the SC173 and SC174 to work with ceramic input and output capacitors. This, together with no external compensation components optimizes bill-of-material (BOM) costs and reduces time-to-design.

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

Availability: Immediately in volume production. Evaluation boards (SC174EVB and SC173EVB) are also available.
Pricing: $1.80 for the SC173 and $1.90 for the SC174 each in quantities of 3,000.
Ordering codes are SC174MLTRT and SC173MLTRT.