What this driver does and where it fits
The Texas Instruments ULQ2003ADR is a 7-channel NPN Darlington transistor array from the ULx200xA series, designed as a low-side switch for inductive loads. The inverting input polarity means a logic low on the input turns the output on — standard for microcontroller GPIO that defaults high at reset, preventing unintended load activation during power-up.
500 mA per channel — what it means for your load budget
The 500 mA per-output rating is the absolute maximum; running all seven channels simultaneously at full current pushes the package dissipation past the SOIC's thermal limit. For continuous duty, derate per channel or limit the number of active outputs.