# ESDA37LY

**STMicroelectronics** · ESD And Surge Protection (TVS/ESD) · SOT-23

ESDA37LY from STMicroelectronics, in a SOT-23. 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 | I/O1 | passive | Protected line 1 (Transil cathode, unidirectional diode to pin 3), with 37 V min and 43.3 V max breakdown voltage at 1 mA and 36 V stand-off voltage; pins 1 and 2 alone form a bidirectional suppressor. |
| 2 | I/O2 | passive | Protected line 2 (Transil cathode, unidirectional diode to pin 3), with 37 V min and 43.3 V max breakdown voltage at 1 mA and 36 V stand-off voltage; pins 1 and 2 alone form a bidirectional suppressor. |
| 3 | GND | power_in | Common anode of both Transil diodes, connected to ground as the return for ESD and surge current (up to 6.3 A peak pulse current, 8/20 µs). |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | STMicroelectronics |
| Package | SOT-23 |
| Category | Circuit Protection |
| Pins | 3 |

## CAD (KiCad official)

- Symbol: `ESDA37LY`
- Footprint: `Package_TO_SOT_SMD:SOT-23`
- 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files: `esda37ly-etched.step` / `esda37ly-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `esda37ly.step` / `esda37ly.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/esda37ly.pdf) (12 pp, sha256 `ae72cb53fa1cc894`, retrieved 2026-10-07, 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/esda37ly-datasheet.pdf)