Dual-phase synchronous buck controller for 4V to 38V rails
The LTC3857EGN-1#PBF is a dual-output, dual-phase synchronous step-down DC/DC controller from Analog Devices' PolyPhase® series. It drives two independent buck rails or a single rail with interleaved phases, using an external transistor driver output. The controller accepts a 4V to 38V supply range and delivers a positive output configuration with synchronous rectification for efficiency above 95% in typical designs.
Switching frequency and timing flexibility
This lets the designer trade off inductor size against switching losses — lower frequencies suit noise-sensitive audio or high-step-ratio rails, while higher frequencies shrink magnetics for space-constrained boards. The maximum duty cycle of 99.4% supports very low dropout operation, useful when the input rail sags close to the output target.
Control features for sequencing and protection
Built-in control features include an enable pin for sequencing, soft-start to limit inrush, power-good output for rail monitoring, and output voltage tracking for supply-rail sequencing in multi-rail systems. The tracking function allows the second output to follow the first during startup and shutdown — critical for FPGA and SoC core voltages that must not lag the I/O rail.
It is ROHS3 compliant (lead-free), so it meets the EU RoHS exemption-free standard.
For urgent BOM fills, we can source from multiple inventory partners.