Eight-channel Darlington relay and solenoid driver
The STMicroelectronics ULN2802A integrates eight NPN Darlington pairs in a single 18-pin DIP, each rated for 500 mA continuous collector current and a 50 V collector-emitter breakdown. The 1000 minimum DC current gain at 350 mA means the base-drive current from a logic gate or microcontroller output stays below 500 µA per channel — no external driver transistor needed between a 5 V CMOS output and a 24 V relay coil. With a maximum Vce saturation of 1.6 V at 500 µA base current and 350 mA load, the on-state voltage drop across the output transistor stays low enough that the power dissipated in the package (2.25 W total across all eight channels) does not force a heatsink in most bench or panel applications — provided the combined load current stays within the package thermal budget.
Through-hole DIP package and thermal profile
Housed in the standard 18-lead 0.300-inch wide DIP (EIAJ/IPC 18-DIP), the ULN2802A mounts directly into a through-hole socket or solders into a plated-through-hole PCB. The 7.62 mm row spacing matches legacy prototyping boards and industrial I/O modules that still use DIP footprints — a deliberate choice for designs that need hand-solderability or socketed replacement. The junction temperature range spans -20°C to 150°C, which covers most indoor industrial and commercial enclosures. The 2.25 W total power dissipation is the sum of all eight channels' conduction loss plus any transient peaks; derating applies above 25°C ambient, and a 150°C junction ceiling means the part survives brief overloads without immediate failure.
Active production and compliance posture
The part ships in Tube packaging and carries a ROHS3 compliance rating, which covers the ten restricted substances plus the four phthalates under EU 2015/863. No REACH or UL documentation is confirmed in the listing, but the ROHS3 declaration is the baseline for EU-market shipments. For a BOM that needs a proven Darlington array in a through-hole package, this part is a direct drop-in for the industry-standard pinout shared by the ULN2003A family (though the ULN2802A offers eight channels versus seven). The active status means authorized-channel supply is the normal route; if a shortage hits, independent inventory with date-code traceability is the fallback — but the laser etch and package markings should match ST's plant font for the week code on the tube label.