The Toshiba TBD62781APG is an 8-channel high-side power switch array built with P-channel MOSFET outputs, each rated for 400 mA continuous and a 50 V maximum load voltage. Typical on-resistance of 1.6 Ω means at full rated current each channel drops about 640 mV and dissipates 256 mW — in an 18-pin DIP without a heatsink, that adds up fast if all eight channels run near the limit. The 1:1 input-to-output ratio with non-inverting logic and no Vcc supply pin (the gate drive is self-biased from the load) simplifies the interface: a logic-high on the input turns the corresponding output on. This part is aimed at driving resistive and inductive loads like relays, solenoids, lamps, and small motors in industrial control panels, programmable logic controllers, and vending or gaming machines.
Thermal budget in a DIP — the 400 mA per-channel limit
The 400 mA per-channel rating is the absolute maximum at 25°C ambient; in practice, the 18-DIP's thermal impedance (junction-to-ambient around 70–90°C/W, typical for a DIP without airflow) limits the total simultaneous load. If you need all eight channels on at full current, the combined 3.2 A and 2 W dissipation will push the junction above 85°C in still air. For continuous duty above 200 mA per channel, forced airflow or a socket with a heat-sinking contact is worth considering.
For a through-hole power driver in a mature package, this part remains a safe choice for production lines that still assemble DIPs, and for legacy board support where a surface-mount retrofit would require a layout change.