# 1SMA4740A SMA

**XCH(旭昌辉)** · IC · SMA

1SMA4740A SMA from XCH(旭昌辉), in a SMA. 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 of the zener diode; operated at positive voltage versus the anode in reverse (zener) regulation, with the 1SMA4740A at 10 V nominal VZ (9.50 V min to 10.5 V max) at IZT = 25 mA, and 1 W maximum total power dissipation. |
| 2 | A | passive | Anode of the zener diode; forward voltage is max 1.2 V at IF = 200 mA, with junction and storage temperature range of -55 to +150 °C. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | XCH(旭昌辉) |
| Package | SMA |
| Category |  |
| 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 |
|---|---|---|---|---|---|---|---|
| Zener voltage (1SMA4740A, nominal 10 V) | VZT | 9.5 | 10 | 10.5 | V | at IZT (test current 25 mA); VZT tested with pulses (20 ms) | 2 |
| Dynamic impedance | ZZT |  |  | 7 | Ω | at IZT = 25 mA | 2 |
| Admissible Zener current | IZM |  |  | 95 | mA |  | 2 |
| Power dissipation | PD |  |  | 1 | W | Tc = 75 °C (series rating, 1SMA4728A thru 1SMA4777A) | 1 |
| Forward voltage | VF |  |  | 1.2 | V | IF = 200 mA | 1 |
| Junction temperature range | TJ | -55 |  | 150 | °C |  | 1 |
| Storage temperature range | TS | -55 |  | 150 | °C |  | 1 |

## CAD (KiCad official)

- Symbol: `1SMA4740A SMA`
- Footprint: `Diode_SMD:D_SMA`
- 3D model: SMA (KiCad packages3D, STEP)
- 3D model files: `1sma4740a-sma-etched.step` / `1sma4740a-sma-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `1sma4740a-sma.step` / `1sma4740a-sma.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [XCH(旭昌辉) datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8603157446084861952) (3 pp, sha256 `8898909dec2ee3ad`, retrieved 2026-10-17, tier: lcsc)
- **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/1sma4740a-sma-datasheet.pdf)