Phase Extender, Slave Step-Down Controller for up to 240A
A dual-phase synchronous step-down slave controller, the LTC3870, that can generate currents up to 240A when paired with a companion master controller by extending the phase count in multiphase applications has been added to the line-up at Linear Technology Corp.. Compatible master controllers include the LTC3880 and LTC3883 digital power system management controllers. The LTC3870 is an alternative to Linear Technology's full-featured controllers and provides the essential functions for multiphase slave designs.
It operates over an input voltage range of 4.5V to 60V and produces a fixed output voltage up to 14V. Up to 12 phases can be paralleled and clocked out-of-phase to minimize filtering. Its peak current-mode architecture allows for accurate phase-to-phase current sharing even for dynamic loads. Applications include power distribution, redundant (n+1) supplies, industrial systems, DSP and ASIC power.
The LTC3870 has a fixed operating frequency from 250kHz to 1MHz, or it can be synchronized to an external clock. The 1.1-Ohm onboard all N-channel gate drivers minimize MOSFET switching losses. Precise programmable current sense threshold limits from 50mV to 72mV minimize power loss and accurately set the overcurrent trip point.
Additional features include selectable continuous or discontinuous light load operation, programmable phase shift control and overvoltage protection. The LTC3870 is available in a 28-lead 4mm x 5mm QFN package. The 1,000-piece price starts at $2.35 each.
