Synchronous buck controller for 4V to 38V rails
It drives external N-channel MOSFETs to deliver a regulated positive output from input rails spanning 4V to 38V, making it suitable for intermediate bus conversion in industrial, telecom, and automotive power systems. The controller operates with a programmable switching frequency from 250kHz to 750kHz, letting the designer trade inductor size against switching losses. The 99% maximum duty cycle allows the output to stay in regulation through input voltage dips nearly down to the output voltage, useful for hold-up or battery-backed designs. Control features include current limit, enable input, frequency control via an external resistor, programmable soft start, and output tracking for supply sequencing.
Housed in a 16-lead WFQFN with exposed pad (3mm x 3mm body), the LTC3851IUD#PBF is a surface-mount device. The supplier device package is 16-QFN (3x3).