ULN2003

September 26, 2014

3112

ULN2003 is a high voltage and high current Darlington array IC. It contains seven open collector darlington pairs with common emitters. A darlington pair is an arrangement of two bipolar transistors.

ULN2003 belongs to the family of ULN200X series of ICs. Different versions of this family interface to different logic families. ULN2003 is for 5V TTL, CMOS logic devices. These ICs are used when driving a wide range of loads and are used as relay drivers, display drivers, line drivers etc. ULN2003 is also commonly used while driving Stepper Motors. Refer Stepper Motor interfacing using ULN2003.

Each channel or darlington pair in ULN2003 is rated at 500mA and can withstand peak current of 600mA. The inputs and outputs are provided opposite to each other in the pin layout. Each driver also contains a suppression diode to dissipate voltage spikes while driving inductive loads. The schematic for each driver is given below:

Pin Description:

Pin No	Function	Name
1	Input for 1^st channel	Input 1
2	Input for 2^nd channel	Input 2
3	Input for 3^rd channel	Input 3
4	Input for 4^th channel	Input 4
5	Input for 5^th channel	Input 5
6	Input for 6^th channel	Input 6
7	Input for 7^th channel	Input 7
8	Ground (0V)	Ground
9	Common free wheeling diodes	Common
10	Output for 7^th channel	Output 7
11	Output for 6^th channel	Output 6
12	Output for 5^th channel	Output 5
13	Output for 4^th channel	Output 4
14	Output for 3^rd channel	Output 3
15	Output for 2^nd channel	Output 2
16	Output for 1^st channel	Output 1