component
SR3.3
Public Made by Adomby adom
TECH PUBLIC ESD And Surge Protection (TVS/ESD), SOT-143. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
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SR3.3
TECH PUBLIC · ESD And Surge Protection (TVS/ESD) · SOT-143
SR3.3 from TECH PUBLIC, 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 | GND | power_in | Common lower rail of the diode array, where the steering diodes from pins 2 and 3 return and the TVS diode connects to pin 4; the datasheet specifies CJ 0.6 pF typ (0.9 pF max) from IO to GND at VR=0V, f=1MHz. |
| 2 | IO1 | passive | Protected I/O line steered by diodes to the pin 4 and pin 1 rails; CJ 0.6 pF typ (IO to GND) and 0.3 pF typ (IO to IO), reverse working voltage 3.3V max, ESD ±30kV air/contact per IEC 61000-4-2. |
| 3 | IO2 | passive | Protected I/O line steered by diodes to the pin 4 and pin 1 rails; CJ 0.6 pF typ (IO to GND) and 0.3 pF typ (IO to IO), reverse working voltage 3.3V max, ESD ±30kV air/contact per IEC 61000-4-2. |
| 4 | VCC/TVS+ | power_in | Common upper rail of the diode array, where the steering diodes from pins 2 and 3 connect and the TVS diode connects to pin 1; breakdown voltage 4.2V min at 1mA and reverse working voltage 3.3V max. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | TECH PUBLIC |
| Package | SOT-143 |
| Category | Circuit Protection |
| Pins | 4 |
CAD (KiCad official)
- Symbol:
SR3.3 - Footprint:
Package_TO_SOT_SMD:SOT-143 - 3D model: SOT-143 (KiCad packages3D, STEP)
- 3D model files:
sr3-3-etched.step/sr3-3-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);sr3-3.step/sr3-3.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: TECH PUBLIC datasheet (4 pp, sha256
036b584d4cd00a58, retrieved 2026-10-18, tier: lcsc) - Extractor: parts-factory
2.0.0/extract_pins 0.3, primaryclaude-sonnet-5-5(vision), consensusclaude-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).
# SR3.3
**TECH PUBLIC** · ESD And Surge Protection (TVS/ESD) · SOT-143
SR3.3 from TECH PUBLIC, 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 | GND | power_in | Common lower rail of the diode array, where the steering diodes from pins 2 and 3 return and the TVS diode connects to pin 4; the datasheet specifies CJ 0.6 pF typ (0.9 pF max) from IO to GND at VR=0V, f=1MHz. |
| 2 | IO1 | passive | Protected I/O line steered by diodes to the pin 4 and pin 1 rails; CJ 0.6 pF typ (IO to GND) and 0.3 pF typ (IO to IO), reverse working voltage 3.3V max, ESD ±30kV air/contact per IEC 61000-4-2. |
| 3 | IO2 | passive | Protected I/O line steered by diodes to the pin 4 and pin 1 rails; CJ 0.6 pF typ (IO to GND) and 0.3 pF typ (IO to IO), reverse working voltage 3.3V max, ESD ±30kV air/contact per IEC 61000-4-2. |
| 4 | VCC/TVS+ | power_in | Common upper rail of the diode array, where the steering diodes from pins 2 and 3 connect and the TVS diode connects to pin 1; breakdown voltage 4.2V min at 1mA and reverse working voltage 3.3V max. |
## Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | TECH PUBLIC |
| Package | SOT-143 |
| Category | Circuit Protection |
| Pins | 4 |
## CAD (KiCad official)
- Symbol: `SR3.3`
- Footprint: `Package_TO_SOT_SMD:SOT-143`
- 3D model: SOT-143 (KiCad packages3D, STEP)
- 3D model files: `sr3-3-etched.step` / `sr3-3-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `sr3-3.step` / `sr3-3.glb` are the bare package body.
## Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- **Datasheet:** [TECH PUBLIC datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8602998837275336704) (4 pp, sha256 `036b584d4cd00a58`, retrieved 2026-10-18, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-sonnet-5-5` (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/sr3-3-datasheet.pdf)