Darlington Array 8 NPN, 2803, DIP18 Package

The STMICROELECTRONICS ULN2803A is a high-performance eight-channel Darlington transistor array housed in a convenient 18-pin DIP (Dual In-line Package). This integrated circuit is specifically engineered to drive high-current loads directly from low-power digital logic circuits, making it an essential component for interfacing microcontrollers, microprocessors, and other logic families with demanding peripheral devices.

Each of the eight Darlington pairs features common emitters and integral suppression (flyback) diodes, which are crucial for safely driving inductive loads such as relays, solenoids, stepper motors, and lamps. This built-in protection eliminates the need for external diodes, simplifying circuit design and improving reliability. The array offers a robust output capability, with a peak load current rating of 600mA and a continuous current rating of 500mA per channel, capable of withstanding up to 50V in the OFF state.

Key Features & Design Benefits

• Simplified Interfacing: Includes 2.7kOhm input resistors, allowing direct connection to 5V TTL and CMOS logic families without the need for additional current-limiting components.
• Optimised Board Layout: Inputs are pinned opposite to the outputs, a design feature that greatly simplifies printed circuit board (PCB) routing and reduces potential for noise.
• Enhanced Current Capacity: Outputs can be paralleled together to achieve a higher total current capability for driving particularly demanding loads.
• Wide Operating Range: Designed for reliable performance across an operating ambient temperature range of -20°C to +85°C, with a total power dissipation (Pd) of 2.25W.

Specifications

• Transistor Polarity: NPN
• Number of Channels: 8 Outputs
• Collector-Emitter Voltage (Vceo): 50V
• DC Collector Current (Continuous): 500mA
• DC Current Gain (hFE): 100