# BZB784-C3V9

**Nexperia** · Zener Diodes · SOT-323(SC-70)

BZB784-C3V9 from Nexperia, in a SOT-323(SC-70). 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 of the first voltage regulator diode; the datasheet gives no pin-specific limit beyond the device totals (Ptot 350 mW with 2 diodes loaded, 180 mW with 1 diode loaded, IF max 200 mA). |
| 2 | cathode | passive | Cathode of the second voltage regulator diode; the datasheet gives no pin-specific limit beyond the device totals (Ptot 350 mW with 2 diodes loaded, 180 mW with 1 diode loaded, IF max 200 mA). |
| 3 | common anode | passive | Common anode shared by both diodes, connecting to the anode side of the two cathode pins 1 and 2 in the SOT323 (SC-70) package. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Nexperia |
| Package | SOT-323(SC-70) |
| Category | Diodes |
| Pins | 3 |

## Electrical characteristics

Limits as printed in the datasheet (page.json `metadata.characteristics` carries them as data).

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Continuous forward current | IF |  |  | 200 | mA |  | 3 |
| Non-repetitive peak reverse current | IZSM |  |  | 6 | A | tp = 100 μs; square wave; Tamb = 25 °C; prior to surge | 5 |
| Total power dissipation (2 diodes loaded) | Ptot |  |  | 350 | mW | Tamb = 25 °C; 2 diodes loaded; note 1 | 3 |
| Total power dissipation (1 diode loaded) | Ptot |  |  | 180 | mW | Tamb = 25 °C; 1 diode loaded | 3 |
| Non-repetitive peak reverse dissipation | PZSM |  |  | 40 | W | tp = 100 μs; square wave; Tamb = 25 °C; prior to surge | 3 |
| Storage temperature | Tstg | -65 |  | 150 | °C |  | 3 |
| Junction temperature | Tj |  |  | 150 | °C |  | 3 |
| Thermal resistance junction to soldering point (2 diodes loaded) | Rth j-s |  | 140 |  | K/W | 2 diodes loaded; note 1 | 4 |
| Thermal resistance junction to soldering point (1 diode loaded) | Rth j-s |  | 265 |  | K/W | 1 diode loaded; note 1 | 4 |
| Thermal resistance junction to ambient (2 diodes loaded) | Rth j-a |  | 355 |  | K/W | 2 diodes loaded; note 2 | 4 |
| Thermal resistance junction to ambient (1 diode loaded) | Rth j-a |  | 680 |  | K/W | 1 diode loaded; note 2 | 4 |
| Forward voltage | VF |  |  | 0.9 | V | IF = 10 mA; see Fig.2 | 4 |
| Reverse current | IR |  |  | 3 | μA | VR = 1 V | 4 |
| Working voltage | VZ | 3.7 |  | 4.1 | V | at IZ = 5 mA; Tj = 25 °C | 5 |

## CAD (KiCad official)

- Symbol: `BZB784-C3V9`
- Footprint: `Package_TO_SOT_SMD:SOT-323_SC-70`
- 3D model: SOT-323(SC-70) (KiCad packages3D, STEP)
- 3D model files: `bzb784-c3v9-etched.step` / `bzb784-c3v9-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `bzb784-c3v9.step` / `bzb784-c3v9.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Nexperia datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8588915887059980288) (9 pp, sha256 `3f7233f6a26109d3`, retrieved 2026-10-20, tier: lcsc)
- **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/bzb784-c3v9-datasheet.pdf)