Buck-boost controller with synchronous rectification
The LTC3780EUH#TRPBF is a single-phase, positive-output buck-boost switching regulator controller from Analog Devices. It drives external N-channel MOSFETs in a four-switch topology that regulates the output whether the input rail is above, below, or equal to the target voltage — no need for a separate boost stage or a post-regulator when the battery voltage crosses the output setpoint. The controller operates from a 4 V to 30 V supply rail and switches between 200 kHz and 400 kHz, set by an external timing resistor. The 99% maximum duty cycle lets it maintain regulation through deep-dropout conditions where the input falls close to the output.
Industrial temperature range and QFN footprint
The 32-lead WFQFN with exposed pad (5 mm × 5 mm) pulls heat into the PCB ground plane; the datasheet's recommended land pattern and thermal-via array are required to keep the junction below the 85°C ceiling at full load. Control features include current limit, enable, power-good flag, and a programmable soft-start that ramps the output without inrush overshoot. The synchronous rectifier driver eliminates the freewheeling Schottky diode in most designs — the external bottom MOSFET's body diode handles the dead-time conduction, and the synchronous switch recovers the inductor energy that a diode would dissipate.
The 32-QFN (5×5) package is MSL-1 per J-STD-020 (moisture sensitivity level 1), meaning no bake required before reflow if the shelf life in the sealed bag has not been exceeded.