# ULN2804A

**STMicroelectronics** · Darlington Transistor Arrays · DIP-18

ULN2804A from STMicroelectronics, in a DIP-18. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

## Pinout

| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | IN1 | input | Input of Darlington driver 1 (10.5 kΩ input resistor for 6-15 V CMOS/PMOS on ULN2804A), drives OUT1; absolute maximum input voltage 30 V. |
| 2 | IN2 | input | Input of Darlington driver 2 (10.5 kΩ input resistor for 6-15 V CMOS/PMOS on ULN2804A), drives OUT2; absolute maximum input voltage 30 V. |
| 3 | IN3 | input | Input of Darlington driver 3 (10.5 kΩ input resistor for 6-15 V CMOS/PMOS on ULN2804A), drives OUT3; absolute maximum input voltage 30 V. |
| 4 | IN4 | input | Input of Darlington driver 4 (10.5 kΩ input resistor for 6-15 V CMOS/PMOS on ULN2804A), drives OUT4; absolute maximum input voltage 30 V. |
| 5 | IN5 | input | Input of Darlington driver 5 (10.5 kΩ input resistor for 6-15 V CMOS/PMOS on ULN2804A), drives OUT5; absolute maximum input voltage 30 V. |
| 6 | IN6 | input | Input of Darlington driver 6 (10.5 kΩ input resistor for 6-15 V CMOS/PMOS on ULN2804A), drives OUT6; absolute maximum input voltage 30 V. |
| 7 | IN7 | input | Input of Darlington driver 7 (10.5 kΩ input resistor for 6-15 V CMOS/PMOS on ULN2804A), drives OUT7; absolute maximum input voltage 30 V. |
| 8 | IN8 | input | Input of Darlington driver 8 (10.5 kΩ input resistor for 6-15 V CMOS/PMOS on ULN2804A), drives OUT8; absolute maximum input voltage 30 V. |
| 9 | GND | power_in | Common emitter ground of all eight Darlington transistors. |
| 10 | COMMON | passive | Common free-wheeling (suppression) diode cathode connection for inductive loads, with clamp diode forward voltage 2 V max at 350 mA. |
| 11 | OUT8 | output | Open-collector Darlington output 8, rated 500 mA continuous (600 mA peak) and 50 V in the OFF state. |
| 12 | OUT7 | output | Open-collector Darlington output 7, rated 500 mA continuous (600 mA peak) and 50 V in the OFF state. |
| 13 | OUT6 | output | Open-collector Darlington output 6, rated 500 mA continuous (600 mA peak) and 50 V in the OFF state. |
| 14 | OUT5 | output | Open-collector Darlington output 5, rated 500 mA continuous (600 mA peak) and 50 V in the OFF state. |
| 15 | OUT4 | output | Open-collector Darlington output 4, rated 500 mA continuous (600 mA peak) and 50 V in the OFF state. |
| 16 | OUT3 | output | Open-collector Darlington output 3, rated 500 mA continuous (600 mA peak) and 50 V in the OFF state. |
| 17 | OUT2 | output | Open-collector Darlington output 2, rated 500 mA continuous (600 mA peak) and 50 V in the OFF state. |
| 18 | OUT1 | output | Open-collector Darlington output 1, rated 500 mA continuous (600 mA peak) and 50 V in the OFF state. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | STMicroelectronics |
| Package | DIP-18 |
| Category | Transistors/Thyristors |
| Pins | 18 |

## CAD (KiCad official)

- Symbol: `ULN2804A`
- Footprint: `Package_DIP:DIP-18_W7.62mm`
- 3D model: DIP-18 (KiCad packages3D, STEP)
- 3D model files: `uln2804a-etched.step` / `uln2804a-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `uln2804a.step` / `uln2804a.glb` are the bare package body.

## Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

- **Datasheet:** [STMicroelectronics datasheet](https://www.st.com/resource/en/datasheet/uln2804a.pdf) (14 pp, sha256 `78d49085c6e74186`, retrieved 2026-10-08, tier: manufacturer)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-sonnet-5-5` (text+vision), consensus `claude-opus-5-5` (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
- **CAD:** KiCad official libraries (CC-BY-SA 4.0).

[Datasheet PDF](docs/uln2804a-datasheet.pdf)