Boost converters suit low-voltage applications

A Semtech product story

Edited by the Electronicstalk editorial team Jul 23, 2010

Semtech has announced a boost converter platform offering what it claims are the world's smallest step-by-step regulators for low-voltage applications.

The SC120, SC121 and SC122 boost inputs from as low as 0.7V to a regulated output settable from 1.8V to 5.0V and are available in 1.5 x 2mm ultra-slim (0.6mm maximum) plastic packages.

The devices are ideally suited for portable applications powered by alkaline, NiMH, or one-cell Li-ion batteries, or as point-of-load regulators in non-portable applications where a low voltage needs to be boosted to a higher voltage rail for localised use.

The SC120 features and performance include: 1.2MHz low-noise PWM operation; an internal low-on-resistance switch and synchronous rectifier for up to 94 per cent efficiency; automatic PSAVE mode for light-load efficiency; an anti-ringing circuit that dampens stray oscillations on the inductor terminal; +/- 1.5 per cent initial accuracy; internal/external feedback modes; soft-start, thermal and current limit protection; and a 0.1uA real shutdown mode that reverses the rectifier's body-diode and actively discharges the output fully to ground.

For highly noise-sensitive applications, the SC121 eliminates the PSAVE mode in favour of forced-PWM operation at all loads.

For specialised keep-alive applications, the SC122 utilises PSAVE mode only and allows the output voltage to float high during shutdown by eliminating active discharge.

The SC122 also limits the input to no more than 1.6V and the output to a fixed 3.3V.

For ease-of-use, the SC12x devices utilise internal loop compensation and internal soft-start to minimise external components.

Grounding the feedback pin enables internally fixed 3.3V regulation mode, which requires three small external components: two ceramic capacitors and an inductor.

For setting other output voltages from 1.8V to 5.0V via external feedback, only two small resistors and a small feed-forward capacitor are added.

The SC120, SC121 and SC122 are available in a 1.2 x 2mm, six-pin MLPD-UT package.

The SC120 is also available in a six-pin SOT23 package.

All devices are lead-free, halogen-free, and WEEE and RoHS compliant to meet worldwide environmental and regulatory requirements.

Evaluation boards (SC120EVB, SC121SKEVB, SC121EVB, and SC122EVB) are also available.

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