Dual NPN in a compact SC-74 — what the 45 V / 500 mA rating means on the board
The Infineon BC817UE6327HTSA1 is a dual NPN transistor in a SC-74, SOT-457 surface-mount package, integrating two matched 45 V collector-emitter breakdown, 500 mA collector current devices on a single substrate. With a minimum DC current gain (hFE) of 160 at 100 mA collector current and 1 V VCE, it is sized for medium-current switching and linear amplification in space-constrained designs — motor pre-drive stages, relay and solenoid coil drivers, signal-level line drivers, and load switches where two transistors share a common footprint. The 170 MHz transition frequency (fT) supports switching up into the low-MHz range, adequate for PWM frequencies in motor control and DC-DC converter feedback loops. Maximum power dissipation is 330 mW, so the thermal budget in a dense board needs checking when both transistors run near the 500 mA ceiling simultaneously.
Last Buy — the sourcing window is closing
Infineon has placed the BC817UE6327HTSA1 in Last Buy status. That means the final production run is in progress or has closed, and once franchised-distributor inventory is exhausted, the part will only be available through independent surplus and broker channels. The BC817 base product number covers a range of single and dual NPN variants in different packages and gain groupings — a cross-reference to an active BC817-series part in the same SC-74 footprint may be possible, but the exact hFE bin and package suffix need verification against the original design's test limits.
Package and rework — SC-74 / SOT-457 handling notes
The SC-74 (SOT-457) is a 6-lead surface-mount package with a 1.5 mm body width and 0.95 mm pin pitch — standard for small-signal dual transistors. Reflow profile follows standard MSL 1 / MSL 3 moisture sensitivity (verify on the reel label); if the moisture barrier bag has been open beyond the floor-life window, a 24-hour bake at 125 °C is needed before reflow to prevent popcorning. Hot-air rework is straightforward at 300–320 °C with a 2–3 second dwell per lead. The package is lead-free compatible (RoHS), but the specific plating finish should be confirmed from the date code lot — older production may use SnPb plating.