300 mA per channel — sizing the load budget
The headline output rating is 300 mA per driver, specified for the low-side (sinking) current only — there is no high-side sourcing capability, as the outputs are open-collector. When sizing the load, remember that both channels share the same package thermal path; driving both near the 300 mA limit simultaneously at 70°C ambient requires checking the derating curve. For a single relay or lamp load at 200 mA, the SN75451BP runs cool with margin.
Through-hole 8-DIP — board fit and rework
The 8-DIP (0.300" row spacing) package is a through-hole part, which means it plugs into a socket or solders into plated-through holes. For prototyping, a DIP socket lets you swap drivers without desoldering. In production, through-hole adds assembly cost versus surface-mount, but for low-volume builds, legacy board repairs, or designs where vibration resistance from a socketed part matters, the 8-PDIP form factor is deliberate.