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Contents

README

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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.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 (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