4 A at 200 V — the conduction and blocking numbers that define the fit
The STTH4R02B-TR is a 4 A average rectified, 200 V reverse-voltage fast recovery diode in the DPAK (TO-252) surface-mount package. The forward voltage drop is 1.05 V max at the full 4 A forward current — at this operating point the conduction loss is 4.2 W, which sets the minimum copper area on the DPAK tab pad to keep the junction below the 175 °C maximum. Reverse leakage is 3 µA typical at the 200 V blocking voltage and 25 °C junction — negligible for the off-state loss budget, but it doubles roughly every 10 °C rise, so at 125 °C junction the leakage contribution should be factored into the standby power calculation.
30 ns reverse recovery — the switching-speed parameter for the converter design
The 30 ns reverse recovery time (trr) places this diode in the fast-recovery class (≤ 500 ns, > 200 mA). In a continuous-conduction-mode boost or flyback converter operating at 100 kHz, a 30 ns trr keeps the reverse-recovery charge low enough that the MOSFET's turn-on loss is dominated by the output capacitance, not the diode tail current. The DPAK package's exposed tab carries the cathode connection and is the primary thermal path. On a typical 2-layer board with 1 oz copper and a 300 mm² pad area under the tab, the junction-to-ambient thermal resistance runs roughly 80 °C/W — the 4.2 W conduction loss at 4 A pushes the junction to about 85 °C above ambient, which keeps the junction well inside the 175 °C ceiling for most ambient temperatures below 85 °C.
Active production, RoHS3 compliant — lifecycle status for the BOM line
ROHS3 compliance covers the ten restricted substances including the four phthalates — no exemption expiry concerns for EU-market shipments. The DPAK package is lead-free and compatible with standard reflow profiles (peak 260 °C).