The STPS3170AFN is a Schottky barrier rectifier from STMicroelectronics rated for 170 V DC reverse voltage and 3 A average forward current, housed in an SMA Flat Leads package for surface-mount assembly.
Fast recovery characteristic and switching application
Reverse leakage is 4 µA at the rated 170 V reverse voltage — low enough to avoid thermal runaway in most 48 V to 170 V bus applications, but leakage rises exponentially with junction temperature, so thermal derating is advised above 125 °C junction.
For a drop-in replacement, the buyer should qualify a same-rated Schottky in the SMA Flat Leads footprint — 170 V, 3 A, 820 mV Vf — from the current STPS3xx or equivalent series.
The SMA Flat Leads package (SMAflat Notch) is a low-profile surface-mount body with flat leads — no J-bend or gull-wing — which simplifies solder-joint inspection and reduces tombstoning risk during reflow. The base product number is STPS3170; the AFN suffix denotes the SMA Flat Leads variant.