# SZMMSZ5248BT1G

**onsemi** · Zener Diodes · SOD-123

SZMMSZ5248BT1G from onsemi, in a SOD-123. 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 | The cathode is indicated by the polarity band on the package, and the device is rated for 500 mW total power dissipation on an FR-5 board at TL = 75°C, derated 6.7 mW/°C above 75°C. |
| 2 | Anode | passive | The anode is the second terminal of the SOD-123 package per the Style 1 pin assignment, and the datasheet states no separate pin-level electrical limits for it. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | onsemi |
| Package | SOD-123 |
| 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 |
|---|---|---|---|---|---|---|---|
| Reverse Zener voltage (nominal 18 V, 5% B-suffix) | VZ | 17.1 | 18 | 18.9 | V | @ IZT 7.0 mA; junction in thermal equilibrium, TL = 30°C ±1°C | 3 |
| Zener voltage tolerance (B suffix) |  | -5 |  | 5 | % | B suffix, standard tolerance on nominal Zener voltage | 3 |
| Maximum Zener impedance | ZZT |  |  | 21 | Ω | @ IZT 7.0 mA; IZ(AC) = 0.1 IZ(dc), f = 1 kHz | 3 |
| Maximum Zener impedance at knee current | ZZK |  |  | 600 | Ω | @ IZK 0.25 mA; IZ(AC) = 0.1 IZ(dc), f = 1 kHz | 3 |
| Reverse leakage current | IR |  |  | 0.1 | µA | @ VR 14 V | 3 |
| Forward voltage | VF |  |  | 0.9 | V | @ IF 10 mA | 3 |
| Total power dissipation on FR-5 board | PD |  |  | 500 | mW | @ TL = 75°C (FR-5 board, Note 1) | 1 |
| Power derating above 75°C | PD |  | 6.7 |  | mW/°C | derated above TL = 75°C | 1 |
| Thermal resistance, junction-to-ambient | RJA |  |  | 340 | °C/W | Junction-to-ambient (Note 2), infrared scan method | 1 |
| Thermal resistance, junction-to-lead | RJL |  |  | 150 | °C/W | Junction-to-lead (Note 2) | 1 |
| Junction and storage temperature range | TJ, Tstg | -55 |  | 150 | °C |  | 1 |

## CAD (KiCad official)

- Symbol: `SZMMSZ5248BT1G`
- Footprint: `Diode_SMD:D_SOD-123F`
- 3D model: SOD-123 (KiCad packages3D, STEP)
- 3D model files: `szmmsz5248bt1g-etched.step` / `szmmsz5248bt1g-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `szmmsz5248bt1g.step` / `szmmsz5248bt1g.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [onsemi datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8589957618002395136) (8 pp, sha256 `7dac1afb22a50027`, retrieved 2026-10-18, tier: lcsc)
- **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/szmmsz5248bt1g-datasheet.pdf)