30 V, 22 A N-channel in a TO-220 — the rail-switch workhorse
The STP22NF03L is a 30 V, 22 A N-channel power MOSFET from STMicroelectronics' STripFET™ II series, housed in a through-hole TO-220 package. It is designed for low-voltage switching applications such as load switches, DC-DC converters, and motor drives in 12 V automotive or industrial systems. The 50 mOhm maximum on-resistance at 11 A gate drive of 10 V keeps conduction losses manageable in continuous operation, while the 9 nC gate charge at 5 V enables reasonably fast switching without a heavy gate-drive burden.
Obsolete — plan the replacement now
For existing BOM lines, a same-function N-channel MOSFET with a 30 V drain-source rating, 22 A continuous drain current, and a TO-220 package should be evaluated for pin-compatible substitution. The 1 V threshold voltage at 250 µA suggests a logic-level gate drive part could match the original switching behaviour without redesigning the gate drive circuit.
The 30 V drain-source voltage gives roughly 2× derating on a 12 V rail, adequate for most automotive load-dump transients if the TVS clamps below 30 V. At lower gate voltages the on-resistance will rise — the drive voltage spec of 5 V to 10 V means the part is optimised for 10 V drive but still functional at 5 V with higher Rds(on).