New chips targeting PSUs

Semtech has unveiled two new devices for the design of isolated power supplies.

Semtech has unveiled two new devices for the design of isolated power supplies for distributed power architectures in telecommunications, data processing, point-of-use industrial systems, space-sensitive switching power supplies, and other applications.

Available in SO-8 packaging, the SC4820 devices are low-power pulse width modulator (PWM) controllers intended for power conversion using push-pull or bridge topologies, typically in point-of-use off-line or DC-to-DC fixed-frequency, current-mode switching power supplies.

Intended for converting a typical 18V to 75V telecommunications supply rail to a 12V supply rail, the SC4820 controller can be adapted to other input voltage ranges. In an example application, the 12V output from the SC4820 controller could be converted to two separate, highly-efficient, well regulated low voltage supplies (3.3V, 5V, etc.), using a device such as Semtech’s complementary dual output SC2420 bi-phase/dual channel secondary side controller.

The SC4820 devices provide improved efficiency and utilisation of the power transformer, as well as providing 250 kHz (SC4820A) and 500 kHz (SC4820B) trimmed switching frequencies.

Devices and evaluation boards are sampling now. Production volumes shipped in tape and reel packaging will be available in December 2000. The devices are priced at $2.08 in 1,000 piece OEM quantities.

Semtech’s are at www.semtech.com.