Dual NPN in a compact TSOT-23-6 — what the ratings tell you
The ROHM QSX8TR is a dual NPN transistor in a TSOT-23-6 package, rated for 30V collector-emitter breakdown and 1A continuous collector current. With a minimum DC current gain of 270 at 100 mA collector current and 2V Vce, it offers high beta for low-base-current drive — useful when the upstream driver is a 3.3V or 5V logic output with limited sourcing capability. The 320 MHz transition frequency marks it as a fast-switching device suited for DC-DC converter drive, signal-level translation, or pre-driver stages where the dual die saves board area versus two discrete SOT-23s.
1.25W in a small footprint — thermal reality
The 1.25W maximum power dissipation in the TSOT-23-6 package means the junction-to-ambient thermal path is constrained. At 1A continuous switching, the Vce(sat) of 350 mV at 500 mA gives a rough dissipation of 175 mW per transistor at that point — within the package limit with margin. But if you push both transistors near 1A simultaneously at high duty cycle, the 1.25W ceiling gets tight. The 150°C junction temperature rating is the hard stop; derate the load if the board sees ambient above 85°C. A quick thermal calculation on the combined dissipation against the package rating is the right check before committing the layout.