Quad Darlington array for inductive loads
The STMicroelectronics ULN2074B packs four NPN Darlington pairs into a single 16-PowerDIP, each rated for 1.75 A collector current and 50 V collector-emitter breakdown. This is a classic relay, solenoid, and stepper-motor driver array — the Darlington configuration gives you a gain of several thousand, so a logic-level 2 mA base drive saturates the output at 1.25 A with a Vce(sat) of 1.4 V max.
Package and thermal considerations
The 1 W power ceiling (total across all four channels) sets the thermal budget — at 1.25 A per channel with 1.4 V saturation drop, each channel dissipates roughly 1.75 W under continuous conduction, so the duty cycle or ambient temperature must be managed to stay within the package limit. Operating temperature spans -20°C to 85°C.
Peer comparison — ULN2075B vs ULN2074B
The closest functional sibling is the ULN2075B, which shares the same 4 NPN Darlington topology, 1.75 A switching current, and 1 W power rating in an identical 16-PowerDIP. The deciding difference is the collector-emitter breakdown voltage: 50 V on the ULN2074B versus 80 V on the ULN2075B. If your load rail runs above 50 V, the ULN2075B is the drop-in — same pinout, same footprint, same thermal envelope. The ULN2067B also offers 80 V breakdown with the same current rating and package.