The STMicroelectronics TIP3055 is a classic NPN silicon power transistor in the TO-247-3 through-hole package. The 3 V saturation voltage at 10 A collector current under 3.3 A base drive is a key number for thermal design — that's about 30 W of conduction loss at full rated current, which demands a substantial heatsink. The TO-247-3 package is a workhorse: three leads, a metal tab for screw-mounting to a heatsink, and it survives hot-air rework well — the leads are thick enough to take a desoldering iron without lifting a pad.
STMicroelectronics no longer manufactures this part in volume. For a production BOM, this means the primary channel is closed — you're looking at the surplus and broker market to fill orders. The TO-247-3 footprint is common across many power transistors, so a pin-compatible replacement is feasible, but you'll need to compare saturation voltage, gain, and switching speed against your application's requirements.
Sourcing reality for the TIP3055
Because this part is obsolete, standard distribution stock is depleted. We source the TIP3055 through our independent supply network — new-old-stock and surplus inventory from verified brokers. If you have a BOM line that needs filling, send us the quantity and target price; we'll pull from our multi-source channel to match it. No minimums beyond what the lot size dictates.