ULN2004ADR – TEXAS INSTRUMENTS

The ULN2004ADR is a monolithic Darlington transistor array integrated circuit, housed in a 16-pin plastic DIP package. It comprises seven independent Darlington pairs, each featuring a high-voltage, high-current output transistor capable of withstanding a collector-emitter voltage (Vceo) of 50V and sustaining a collector current (Ic) of 500mA. Each Darlington pair incorporates a free-wheeling diode for inductive load protection, crucial for driving inductive loads like relays and solenoids. The input logic voltage range is typically 1.5V to 7V, allowing compatibility with various logic families. The device operates efficiently within a typical ambient temperature range of -25°C to +85°C._x000D_
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The ULN2004ADR’s primary advantage lies in its ability to directly drive high-power loads from low-power logic signals, eliminating the need for discrete transistors and associated circuitry. This simplifies design, reduces component count, and minimizes board space. Common applications include driving relays in industrial control systems, controlling stepper motors in low-power applications, and interfacing with electromechanical actuators. However, the 500mA current limit per channel should be carefully considered when selecting loads. Its inherent protection diodes mitigate the risks associated with inductive switching transients. Careful attention to heatsinking may be required for sustained high-current operation.