# CD143A-SR70

**BOURNS** · ESD And Surge Protection (TVS/ESD) · SOT-143

CD143A-SR70 from BOURNS, in a SOT-143. 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 | VN | power_in | Pin 1 (VN) is a rail terminal of the steering diode array as labeled in the Device Pinout table; the datasheet gives no separate voltage or current limit for this pin, only device-level ratings such as 70 V repetitive peak reverse voltage and 85 V reverse breakdown voltage. |
| 2 | I/O 1 | bidirectional | Pin 2 (I/O 1) is one of the two protected data/signal lines, with ESD protection of ±8 kV contact and ±15 kV air discharge per IEC 61000-4-2 and a 3 pF typical capacitance between I/O pins. |
| 3 | I/O 2 | bidirectional | Pin 3 (I/O 2) is the second protected data/signal line, with ESD protection of ±8 kV contact and ±15 kV air discharge per IEC 61000-4-2 and a 3 pF typical capacitance between I/O pins. |
| 4 | VP | power_in | Pin 4 (VP) is a rail terminal of the steering diode array as labeled in the Device Pinout table; the datasheet gives no separate voltage or current limit for this pin, only device-level ratings such as 70 V repetitive peak reverse voltage and 85 V reverse breakdown voltage. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | BOURNS |
| Package | SOT-143 |
| Category | Circuit Protection |
| Pins | 4 |

## Electrical characteristics

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

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Capacitance | Cj |  |  | 10 | pF | @ 0 V 1 MHz, measured between I/O pins and ground | 1 |
| Repetitive Peak Reverse Voltage |  |  |  | 70 | V |  | 1 |
| Reverse Breakdown Voltage | VBR | 85 |  |  | V | I @ 50 μA | 1 |
| Forward Clamping Voltage | VFC |  |  | 1.5 | V | 8/20 μs IPP @ 1 A | 1 |
| Forward Clamping Voltage | VFC |  |  | 7 | V | 8/20 μs IPP @ 24 A | 1 |
| Reverse Leakage Current | IR |  |  | 1 | μA | @ VRRM | 1 |
| ESD Protection Contact Discharge |  |  |  | 8 | kV | IEC 61000-4-2 Contact Discharge | 1 |
| ESD Protection Air Discharge |  |  |  | 15 | kV | IEC 61000-4-2 Air Discharge | 1 |
| EFT Protection |  |  |  | 40 | A | IEC 61000-4-4 @ 5/50 ns | 1 |
| Surge Protection |  |  |  | 24 | A | IEC 61000-4-5 @ 8/20 μs, Level 2 (Line-Gnd) & Level 3 (Line-Line) | 1 |
| Forward Peak Pulse Current | IPP |  |  | 24 | A | tp = 8/20 μs | 1 |
| Operating Temperature Range | TJ | -55 | 25 | 150 | °C |  | 1 |
| Storage Temperature Range | TSTG | -55 | 25 | 150 | °C |  | 1 |

## CAD (KiCad official)

- Symbol: `CD143A-SR70`
- Footprint: `Package_TO_SOT_SMD:SOT-143`
- 3D model: SOT-143 (KiCad packages3D, STEP)
- 3D model files: `cd143a-sr70-etched.step` / `cd143a-sr70-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `cd143a-sr70.step` / `cd143a-sr70.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [BOURNS datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8589785120757747712) (4 pp, sha256 `bbd953b40f1387cc`, 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/cd143a-sr70-datasheet.pdf)