ULN2803A Octal Darlington Transistor Array
Darlington Transistor Arrays, SOIC18/DIP18
Aliase:ULN2803, 8-Channel Darlington Driver
DIP-18 Top View
18 Pins
Pinout Table18
| Pin | Signal / Name | Type | Alternative Functions |
|---|---|---|---|
| 1 | I1 | Digital | Input Channel 1 — logic input with integrated 2.7kΩ series resistor; 5V and 3.3V logic compatible; HIGH turns output transistor ON |
| 2 | I2 | Digital | Input Channel 2 |
| 3 | I3 | Digital | Input Channel 3 |
| 4 | I4 | Digital | Input Channel 4 |
| 5 | I5 | Digital | Input Channel 5 |
| 6 | I6 | Digital | Input Channel 6 |
| 7 | I7 | Digital | Input Channel 7 |
| 8 | I8 | Digital | Input Channel 8 |
| 9 | GND | Ground | System Ground (0V) — emitter side of all Darlington transistors |
| 10 | COM | Power | Flyback Diode Common — connect to inductive load supply voltage (e.g., relay coil VCC); catches back-EMF when load switches off; leave open if no inductive loads |
| 11 | O8 | Digital | Open-Collector Output Channel 8 — sinks up to 500mA per channel; max 50V; connect load between output and supply |
| 12 | O7 | Digital | Open-Collector Output Channel 7 |
| 13 | O6 | Digital | Open-Collector Output Channel 6 |
| 14 | O5 | Digital | Open-Collector Output Channel 5 |
| 15 | O4 | Digital | Open-Collector Output Channel 4 |
| 16 | O3 | Digital | Open-Collector Output Channel 3 |
| 17 | O2 | Digital | Open-Collector Output Channel 2 |
| 18 | O1 | Digital | Open-Collector Output Channel 1 |