40 A, 300 V standard recovery diode in a fully isolated TO-220FP
The STMicroelectronics STTH40P03SFP is a standard recovery rectifier diode rated for 300 V DC reverse voltage and 40 A average rectified current, housed in a TO-220-3 Full Pack (TO-220FP) through-hole package. Forward voltage is specified at 1.1 V at 40 A, with a reverse leakage of 50 µA at 300 V. The junction temperature maximum is 175°C. Recovery time is standard recovery (>500 ns, >200 mA), placing this part in the line-frequency rectification class rather than fast-switching applications.
Obsolete — no direct ST replacement on record
For a production BOM line, the practical path is either to qualify a functionally equivalent standard-recovery 300 V, 40 A diode in a TO-220FP package from another manufacturer, or to source remaining stock through independent distribution. Date-code provenance matters here — stock surfacing well after the last-time-buy window should be verified against the manufacturer PCN before accepting into inventory.
The standard recovery classification (>500 ns, >200 mA) tells you this diode is optimised for 50/60 Hz line-frequency rectification, not for high-frequency switching supplies or PFC stages. In a 300 V, 40 A bulk rectifier role — think input bridge in a power supply, battery charger output, or motor drive DC bus — the slower recovery is fine and typically yields a lower forward voltage drop than an ultrafast part at the same current. If the design calls for switching above a few kilohertz, this part will have excessive reverse recovery losses; an ultrafast or hyperfast diode would be the correct choice.
Package and mounting — TO-220FP isolated tab
The TO-220-3 Full Pack (supplier device package TO-220FP) is a through-hole package with a fully encapsulated metal tab. This saves assembly time and improves thermal transfer, but the thermal resistance junction-to-case is typically higher than a non-isolated TO-220 — budget for heatsink sizing accordingly. The three through-hole leads are on the standard 2.54 mm pitch and fit a common TO-220 footprint.