The Toshiba TTA004B,Q is a PNP silicon transistor in a through-hole TO-126N package, designed for general-purpose switching and amplifier stages where the collector needs to sink up to 1.5 A continuous at a 160 V Vceo ceiling. Rated for 10 W power dissipation at the case, the device's safe operating area is bounded by the junction temperature limit of 150°C — the thermal resistance from junction to case determines the actual derating curve for the target heatsink or board copper.
Switching and gain profile
The 100 MHz transition frequency (fT) places the TTA004B,Q in the audio and low-speed switching band — it handles PWM up to a few hundred kHz with acceptable gain roll-off, but is not intended for RF or high-speed gate drive above 1 MHz.
The TO-126N (TO-225AA variant) is a three-lead through-hole package with a metal tab for heatsinking — the tab is electrically common to the collector, so the mounting hardware must be isolated or the heatsink must float if the collector is not at ground potential. Supplied in Bulk tube — no tape-and-reel option is listed, which is typical for through-hole power transistors destined for hand-insertion or low-volume assembly.
RoHS compliant per the manufacturer's declaration; no additional REACH, UL, or IEC certification is cited in the available documentation.