Dual-phase PMBus controller for high-density POL rails
The LTC3884IUK#PBF is a dual-output, 2-phase step-down switching regulator controller from the PolyPhase® series, integrating an I²C/PMBus serial interface for telemetry and configuration. Operating from a 4.5 V to 38 V supply rail, it drives external N-channel MOSFETs in a buck topology with synchronous rectification, supporting a switching frequency range of 200 kHz to 1 MHz. The 48-lead WFQFN exposed-pad package (7x7 mm) keeps the thermal path short for the controller itself — the power dissipation is in the external FETs, but the pad still needs a solid via-stitch to the ground plane.
PMBus telemetry and control features
Control features include enable, frequency control, phase control, and power-good flagging — the phase-control pin lets you interleave the two channels for ripple cancellation at the output capacitor. The PMBus interface reads output voltage, current, and temperature telemetry, and writes margining and fault-limit registers — useful for ATE or in-system calibration without touching a trim pot. Clock synchronization allows multiple LTC3884 parts to share a common switching edge, reducing beat-frequency ripple on a shared input bus.