The ULQ2003A and ULQ2004A are high-voltage high-current Darlington transistor arrays. Each consists of seven npn Darlington pairs that feature high-voltage outputs with common-cathode clamp diodes for switching inductive loads. The collector-current rating of a single Darlington pair is 500 mA. The Darlington pairs can be paralleled for higher current capability. Applications include relay drivers, hammer drivers, lamp drivers, display drivers (LED and gas discharge), line drivers, and logic buffers.

The ULQ2003A has a 2.7-k series base resistor for each Darlington pair, for operation directly with TTL or 5-V CMOS devices. The ULQ2004A has a 10.5-kseries base resistor to allow operation directly from CMOS devices that use supply voltages of 6 V to 15 V.