# BAS521

**TECH PUBLIC** · Schottky Diodes · SOD-523

BAS521 from TECH PUBLIC, in a SOD-523. 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 | CATHODE | passive | Cathode terminal of the BAS521 Schottky barrier diode, marked PIN1 on the SOD523 package; the datasheet limits are 300 V peak repetitive reverse voltage, 250 mA continuous forward current (TS ≤ 90°C) and 4.5 A peak forward surge current (1 ms square wave). |
| 2 | ANODE | passive | Anode terminal of the BAS521 Schottky barrier diode, marked PIN2 on the SOD523 package; the datasheet limits are a 300 V DC blocking voltage, 250 mA continuous forward current (TS ≤ 90°C) and 1 A repetitive forward current (1 ms). |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | TECH PUBLIC |
| Package | SOD-523 |
| Category | Diodes |
| Pins | 2 |

## CAD (KiCad official)

- Symbol: `BAS521`
- Footprint: `Diode_SMD:D_SOD-523`
- 3D model: SOD-523 (KiCad packages3D, STEP)
- 3D model files: `bas521-etched.step` / `bas521-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `bas521.step` / `bas521.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [TECH PUBLIC datasheet](docs/bas521-datasheet.pdf) (3 pp, sha256 `1054f7a20610ba99`, retrieved 2026-10-21, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-5-5` (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/bas521-datasheet.pdf)