Step-down controller for wide-input industrial rails
The MAX1745EUB+T: The 100% duty-cycle capability means the high-side FET can stay on continuously, useful when the input voltage drops close to the target output — a common scenario in battery-backed or cold-crank systems. Switching frequency runs up to 330 kHz, which sets the practical inductor size and output filter corner. At the upper end of the range, the inductor shrinks, but the switching losses in the external FET and the controller's own gate-drive draw increase. The controller does not include a synchronous rectifier — the low-side freewheeling diode is external, so the bill-of-materials cost stays lower at the expense of efficiency at high step-down ratios.
Package and board-fit for the 10-uMAX footprint
The controller is supplied in a 10-lead TFSOP/MSOP package (3.00 mm body width), with the supplier device package designated 10-uMAX/uSOP. The 0.50 mm lead pitch and exposed die-attach paddle (if present on the variant) demand a PCB layout that keeps the high-current switch node and the sensitive feedback trace separated — the datasheet layout example is the reference, not a suggestion.