ULN2803A 8-channel Darlington array (DIP-18) with ESP32
Supply 3.3-5 V
Bus GPIO
Pins and ESP32 wiring
| Pin | Role | ESP32 pin | Notes |
|---|---|---|---|
| 1B | Input (the ESP32 drives it) | D25 | Pins 1 to 8: inputs, 3.3 V logic works |
| 2B | Input (the ESP32 drives it) | D26 | |
| 3B | Input (the ESP32 drives it) | D27 | |
| 4B | Input (the ESP32 drives it) | D32 | |
| 5B | Input (the ESP32 drives it) | D33 | |
| 6B | Input (the ESP32 drives it) | D23 | |
| 7B | Input (the ESP32 drives it) | D19 | |
| 8B | Input (the ESP32 drives it) | D18 | |
| GND | Ground | GND | Pin 9 |
| COM | Not wired to the ESP32 | — | Pin 10: to the load supply + (flyback diodes inside) |
| 8C | Not wired to the ESP32 | — | Pins 11 to 18: outputs, pull the load to GND (500 mA max each) |
| 7C | Not wired to the ESP32 | — | |
| 6C | Not wired to the ESP32 | — | |
| 5C | Not wired to the ESP32 | — | |
| 4C | Not wired to the ESP32 | — | |
| 3C | Not wired to the ESP32 | — | |
| 2C | Not wired to the ESP32 | — | |
| 1C | Not wired to the ESP32 | — |
Suggested wiring for the 30-pin ESP32 DevKit, avoiding flash, input-only and strapping pins. BoardPilot checks it for you as you wire.
Sources
- Texas Instruments ULN2803A datasheet, Pin functions; 500 mA per channel; 50 V outputs with clamp diodes
Try it in 3D in BoardPilot
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Part data: CC BY 4.0, free to reuse with credit to BoardPilot.