BETAULN2803AEight-channel Darlington driver
Switch eight loads from logic—with the complete power budget in view.
ULN2803A combines eight NPN Darlington drivers and eight clamp diodes in an 18-pin package. Each logic input controls an open-collector output that sinks current through an external load. This reference follows Toshiba ULN2803APG in DIP-18 and ULN2803AFWG in wide SOP-18. Each input has a 2.7 kΩ resistor for TTL or 5 V CMOS control; pin 9 is the shared ground return and pin 10 is the clamp-diode common. Connect COM to the positive coil supply for inductive loads. The 500 mA single-output stress rating is not an eight-channel continuous-current allowance: duty cycle, voltage drop, ambient temperature and package dissipation all matter.
