January 16, 2014 – Linear Technology Korea (CEO Hong Sa-gwak) announced the launch of the LTC3874, a dual synchronous step-down slave controller that generates up to 300A of current when paired with a compatible master controller by extending the number of phases in multi-phase applications. Compatible controllers include the LTC3866, LTC3875, and LTC3774, all of which feature true current mode control, enabling the use of low-DCR (0.2 milliohm) DC resistance power inductors without sense resistors, thereby maximizing converter efficiency and increasing power density.

The LTC3874 complements Linear Technology's low DCR peak current mode controllers and provides all necessary functions for multi-phase slave designs, including accurate inter-phase current sharing even under dynamic loads. The device operates within an input voltage range of 4.5V to 38V and generates a fixed output voltage of up to 5.5V. Up to 12 phases can be paralleled, with phase offset minimizing filtering requirements. Applications include power distribution, redundant (n+1), industrial systems, and power supplies for DSPs and ASICs.

The LTC3874 offers fixed operating frequencies ranging from 250kHz to 1MHz or can be synchronized with an external clock. A robust 1.1 Ohm on-board gate driver minimizes MOSFET switching losses. Precise programmable current sense thresholds of 16mV to 72mV minimize power loss and accurately set overcurrent trip points. Additional features include selectable continuous or discontinuous light load operation, programmable phase transition control, and overvoltage protection.

Photo caption: Phase extender slave step-down controller