The LTC3874 dual-phase synchronous step-down slave controller generates currents up to 200 A when paired with a companion master controller by extending the phase count in multiphase applications. Compatible master controllers include the LTC3866, LTC3875, and LTC3774—all have current-mode control and enable the use of low (0.2 mΩ) dc-resistance (DCR) power inductors without any sense resistor to maximize converter efficiency and boost power density. Developed by Linear Technology, the LTC3874 includes accurate phase-to-phase current sharing, which is critical in multiphase slave designs. Up to 12 phases can be paralleled and clocked out-of-phase to minimize filtering. Input voltage ranges from 4.5 to 38 V; fixed output voltage ranges up to 5.5 V. The device has a fixed operating frequency from 250 kHz to 1 MHz; it also can be synchronized to an external clock. Onboard gate drivers (1.1 Ω) help diminish MOSFET switching losses. Current-sense threshold limits from 16 to 72 mV minimize power loss and accurately set the overcurrent trip point. Packaging is a 28-lead, 4- by 5-mm QFN. Applications include power distribution, redundant (n+1) supplies, industrial systems, digital signal processing, and ASIC power.