What is ULN2803A? – Darlington Sink Driver – Toshiba

What is ULN2803A?

This is a high-voltage, high-current Darlington transistor array. It consists of eight NPN Darlington pairs that feature high-voltage outputs with common-cathode clamp diodes for inductive load transient suppression. The ULN2803A is commonly used in a range of electronic circuits to interface low-level logic to high-power loads, such as motors, solenoids, and lamps.

Part Number: ULN2803A

Function: 8-Channel Darlington Sink Driver

Package:  AP type : DIP-18pin, AFW type-SOL-18pin

Manufacturer: Toshiba

ULN2803A datasheet


The ULN2803A / ULN2803AP / ULN2803AFW Series are high−voltage, high−current darlington drivers comprised of eight NPN darlington pairs. All units feature integral clamp diodes for switching inductive loads. Applications include relay, hammer, lamp and display (LED) drivers. High-voltage, high-current darlington drivers comprised of eight NPN darlington pairs.

Advantages Vs Disadvantages


1. High-current capability
2. High-voltage outputs with inductive load transient suppression
3. Compact size with multiple channels in a single package
4. Low saturation voltage, which reduces power consumption
5. High input impedance and low input current make it easy to drive with low-level logic signals


1. The Darlington pairs have a high saturation voltage, which can lead to power dissipation and heating of the device

2. The ULN2803A does not provide isolation between the input and output, which can be a concern in some applications

3. The device is not suitable for high-speed switching applications


1. Output current (single output) : 500 mA (Max.)

2. High sustaining voltage output : 50 V (Min.)

3. Output clamp diodes

4. Inputs compatible with various types of logic.

ULN2803A Datasheet PDF Download

ULN2803A pdf

Other data sheets are available within the file:

ULN2803, ULN2803AFW, ULN2803AP, ULN2804