30 ns reverse recovery — what it buys the switching node
The STMicroelectronics STTH1R02 is a standard fast-recovery rectifier in a DO-41 axial package, rated for 200 V reverse voltage and 1.5 A average forward current. That trr number means the diode stops conducting fast enough to avoid cross-conduction losses and ringing that would eat into efficiency or radiate. The 1 V forward drop at 1.5 A sets a conduction loss of about 1.5 W — the DO-41 leaded body handles that with adequate PCB lead length or a heatsink clip, but it is not a Schottky; for sub-100 V rails a 40 V Schottky would run cooler.
Leakage and junction temperature — the thermal reality
Reverse leakage is 3 µA at the full 200 V rating, which keeps blocking losses negligible in off-line supplies — no thermal runaway concern at high line. The junction is rated to 175 °C maximum, which gives headroom for the 1.5 W conduction loss plus ambient heat in a cramped chassis. That 175 °C Tj max is typical for ST's fast-recovery Turbo 2 series; it means the part survives a short overload without immediate failure, but continuous operation near that limit shortens life expectancy. For a 105 °C ambient environment, derate the forward current from 1.5 A down to about 1 A using the thermal resistance curve in the datasheet.
DO-41 axial — the package and mounting
The STTH1R02 ships in the DO-204AL / DO-41 axial-leaded package. Through-hole mounting with 0.025-inch diameter leads; the body length is about 5.2 mm. For reflow soldering, the leads are tin-plated and solderable per MIL-STD-750. No moisture sensitivity level concern — the DO-41 epoxy body is hermetic enough for standard factory floor exposure. The Cut Tape (CT) and Tape & Box (TB) packaging options suit both hand-assembly and automated insertion.