It comes in a surface-mount DPAK (TO-252-3) package. This class of diode is typically used as a boost diode in power-factor-correction stages, as a freewheeling diode in flyback converters, or as a snubber clamp in switched-mode power supplies where the 95 ns trr keeps switching losses manageable at frequencies up to the low hundreds of kilohertz.
The 95 ns trr places this diode in the fast-recovery class (≤500 ns at >200 mA). In a continuous-conduction-mode PFC stage running at 70–100 kHz, that recovery time keeps the reverse-recovery charge low enough that the MOSFET turn-on losses stay within budget. If the design pushes toward 200 kHz or higher, a diode with a sub-50 ns trr (such as an SiC Schottky) would be a better fit, but for the majority of 100 W to 300 W offline supplies this recovery speed is well matched to the silicon MOSFETs it typically partners with.
Forward drop and leakage — the thermal side
At 5 A the forward voltage is 1.3 V max, which at full rated current gives about 6.5 W conduction loss — a number that drives the heatsinking decision for the DPAK package. The reverse leakage is 5 µA at 600 V, a figure that roughly doubles every 10 °C rise above 25 °C junction temperature. With a maximum junction temperature of 175 °C, the designer should derate the average current if the ambient forces the junction above 125 °C, or the leakage-induced standby loss can become significant in a no-load condition.
Any stock in the channel is residual inventory or surplus. For a new design or a repair BOM that needs a guaranteed supply, the practical path is to qualify a replacement. ST does not list a direct successor for this exact order code, but the STTH5L06 family shares the same die and package across multiple reel/tube variants — the STTH5L06 series (base product number STTH5L06) is the same silicon in different shipping formats. For a pin-compatible drop-in, look at the STTH5L06FP (TO-220FPAC) if through-hole is acceptable, or the STTH5L06G (D²PAK) for a larger surface-mount footprint. Neither is a direct DPAK replacement, so a board layout change may be needed.