Step-down controller for non-isolated rails
The LTC1771EMS8#TRPBF is a current-mode step-down (buck) switching regulator controller from Analog Devices. It drives an external N-channel MOSFET to regulate a positive output voltage from a 2.8V to 18V input rail. The 100% maximum duty cycle allows the output to approach the input voltage closely, useful for low-dropout regulation where the input rail sags near the target output.
Control features and output stage
The controller provides a single-phase positive output with a transistor-driver stage, meaning it requires an external power MOSFET and inductor to complete the regulator. Synchronous rectification is not implemented internally, so the low-side switch is a Schottky diode. Built-in control features include an enable pin for shutdown and a soft-start pin to limit inrush current during startup. No clock synchronization input is provided. The 2.8V minimum supply voltage lets it operate from 3.3V or 5V intermediate buses, while the 18V maximum covers 12V industrial rails and battery-powered systems.
Housed in an 8-lead MSOP (also compatible with 8-TSSOP footprint), 3.00 mm body width, the package is suited for space-constrained designs. The supplier device package is 8-MSOP.