The STP70NF03L is a 30 V, 70 A N-channel MOSFET from ST's STripFET™ II generation, built for low-voltage power switching in a through-hole TO-220 package. The ±18 V max gate rating means standard 10 V or 12 V gate drives are fine, but logic-level 5 V drive will not achieve the minimum Rds(on) — note the drive voltage spec calls for 5 V minimum and 10 V for the best on-resistance.
100 W dissipation in a TO-220 — thermal planning matters
The 100 W maximum power dissipation is rated at the case temperature (Tc), not ambient — a TO-220 bolted to a heatsink can handle that, but without one the junction will exceed the 175 °C absolute maximum at a fraction of that power. The 175 °C junction rating is military-grade, meaning the die itself can survive sustained high-temperature operation if the thermal path is designed for it. For a 70 A load at 9.5 mOhm, conduction loss alone is about 47 W at full current — well within the 100 W ceiling, but only if the heatsink keeps Tc under control.
Obsolete — sourcing this part today
ST has marked the STP70NF03L as obsolete. The only supply channel is the independent distribution and surplus market — broker-sourced new-old-stock or pulled inventory. Date codes will vary, and the risk of counterfeit or re-marked parts goes up when the factory pipeline is dry.