# ESDAULC45-1BF4

**STMicroelectronics** · ESD And Surge Protection (TVS/ESD) · 0201

ESDAULC45-1BF4 from STMicroelectronics, in a 0201. 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 | Pin 1 | passive | Pin 1 is marked by the bar on the package and is the orientation reference for placement, per the footprint and marking figures; the datasheet gives no separate electrical function or limit for this terminal. |
| 2 | Pin 2 | passive | Pin 2 is the second terminal of this bidirectional single-line ESD protection diode shown in the 0201 footprint; the datasheet gives no separate electrical function or limit for this terminal. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | STMicroelectronics |
| Package | 0201 |
| Category | Circuit Protection |
| Pins | 2 |

## CAD (KiCad official)

- Symbol: `ESDAULC45-1BF4`
- Footprint: `Diode_SMD:D_0201_0603Metric`
- 3D model: 0201, generated from the KiCad footprint (body from the F.Fab outline, terminals on the pads, 0.3 mm nominal _01005_ height). Neither the vendor nor KiCad ships a 3D model for this package, so the dimensions are nominal, not the manufacturer's CAD (STEP)

## Provenance

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

- **Datasheet:** [STMicroelectronics datasheet](https://www.st.com/resource/en/datasheet/esdaulc45-1bf4.pdf) (12 pp, sha256 `b9811d5275f131b1`, retrieved 2026-10-08, tier: manufacturer)
- **Extractor:** `ds2sf` (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
- **CAD:** KiCad official libraries (CC-BY-SA 4.0).

[Datasheet PDF](docs/esdaulc45-1bf4-datasheet.pdf)