750 mA buck with a 42 V input ceiling
The LT3973IMSE#TRPBF is a step-down switching regulator from Analog Devices, built around a current-mode, fixed-frequency buck topology. Its 4.2 V to 42 V input range covers 12 V and 24 V industrial rails with headroom for transients; the 42 V abs-max means a 24 V nominal bus that glitches to 36 V during a load-dump stays inside the safe operating area without an external clamp. The single adjustable output delivers up to 750 mA, with the feedback set point at 1.21 V minimum and a 24 V maximum ceiling.
Package and thermal: 10-MSOP with exposed pad
Housed in a 10-lead MSOP with an exposed pad (3.00 mm width), the part relies on the paddle for heat sinking. The junction temperature range is -40°C to 125°C, which covers under-hood automotive and industrial cabinet ambient without derating. The synchronous rectifier is external (the LT3973 uses a freewheeling diode), so the layout needs a Schottky diode close to the SW pin with short, wide traces. The RT pin programs the switching frequency; a 0.1% resistor keeps the frequency tolerance tight enough for EMI filter design.
Active production, tape-and-reel supply
The TRPBF suffix indicates tape-and-reel packaging — 2,500 pieces per reel — which is the standard volume format for pick-and-place assembly. Cut-tape quantities are also available for prototyping.