# BZX585-B4V3

**Nexperia** · Zener Diodes · SOD-523(SC-79)

BZX585-B4V3 from Nexperia, in a SOD-523(SC-79). 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 | K | passive | Cathode, indicated by the marking bar on the package; the cathode tab is the reference for the stated total power dissipation of 300 mW (device mounted on FR4 PCB with about 35 mm² Cu at the cathode tab) and for the thermal resistance junction-to-solder-point (65 K/W max). |
| 2 | A | passive | Anode of the Zener diode; the datasheet gives no pin-specific limit for this terminal, so the device ratings apply (for example forward current IF max 200 mA and Tj −65 °C to 150 °C). |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Nexperia |
| Package | SOD-523(SC-79) |
| Category | Diodes |
| Pins | 2 |

## Electrical characteristics

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

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Working voltage (B tolerance series, nominal 4.3 V) | VZ | 4.21 |  | 4.39 | V | Tj = 25 °C unless otherwise specified | 4 |
| Working voltage tolerance (B series) | VZ tolerance | -2 |  | 2 | % | Sel B (±2 % series) | 1 |
| Differential resistance (rdiff, upper-current column pair) | rdiff |  | 410 | 600 | Ω | IZ = 1 mA | 4 |
| Differential resistance (rdiff, lower-current column pair) | rdiff |  | 80 | 90 | Ω | IZ = 5 mA | 4 |
| Temperature coefficient | SZ | -3.5 | -1.7 | 0 | mV/K | IZ = 5 mA | 4 |
| Reverse current | IR |  |  | 3 | µA | VR = 1.0 V | 4 |
| Diode capacitance | Cd |  |  | 350 | pF | f = 1 MHz; VR = 0 V | 4 |
| Non-repetitive peak reverse current | IZSM |  |  | 6 | A | tp = 100 µs; square wave; Tj = 25 °C before surge | 4 |
| Forward voltage | VF |  |  | 0.9 | V | IF = 10 mA; pulse test tp ≤ 300 µs; δ ≤ 0.02 | 4 |
| Forward voltage | VF |  |  | 1.1 | V | IF = 100 mA; pulse test tp ≤ 300 µs; δ ≤ 0.02 | 4 |
| Forward current | IF |  |  | 200 | mA |  | 3 |
| Non-repetitive peak reverse power dissipation | PZSM |  |  | 40 | W | tp = 100 µs; square wave; Tamb = 25 °C; prior to surge | 3 |
| Total power dissipation | Ptot |  |  | 300 | mW | Tamb = 25 °C; FR4 PCB, approx. 35 mm² Cu at cathode tab | 3 |
| Junction temperature | Tj | -65 |  | 150 | °C |  | 3 |
| Ambient temperature | Tamb | -65 |  | 150 | °C |  | 3 |
| Storage temperature | Tstg | -65 |  | 150 | °C |  | 3 |
| Thermal resistance, junction to ambient | Rth(j-a) |  |  | 350 | K/W | In free air; FR4 PCB, approx. 35 mm² Cu at cathode tab | 3 |
| Thermal resistance, junction to solder point | Rth(j-sp) |  |  | 65 | K/W | Soldering point of cathode tab | 3 |

## CAD (KiCad official)

- Symbol: `BZX585-B4V3`
- Footprint: `Diode_SMD:D_SOD-523`
- 3D model: SOD-523(SC-79) (KiCad packages3D, STEP)
- 3D model files: `bzx585-b4v3-etched.step` / `bzx585-b4v3-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `bzx585-b4v3.step` / `bzx585-b4v3.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Nexperia datasheet](https://assets.nexperia.com/documents/data-sheet/BZX585-B4V3.pdf) (13 pp, sha256 `ce6f045443a822c0`, retrieved 2026-10-30, tier: manufacturer)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-5-5` (text), consensus `claude-sonnet-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/bzx585-b4v3-datasheet.pdf)