π122E31 from 2Pai Semi, in a SOIC-8-N. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin	Name	Type	Function
1	VDD1	power_in	Supply voltage for Isolator Side 1. Operating range 3.0 V to 5.5 V. Bypass to GND1 with a low-ESR ceramic capacitor (0.1 µF to 10 µF recommended).
2	VOA	output	Logic Output A on Side 1. Digital output of the reverse channel A whose input (VIA) is on Side 2. Drives CMOS levels referenced to VDD1/GND1; IOH/IOL rated ±6 mA.
3	VIB	input	Logic Input B on Side 1. CMOS digital input driving forward channel B whose output (VOB) is on Side 2. VIH ≥ 0.7·VDD1, VIL ≤ 0.3·VDD1; input current ±10 µA max.
4	GND1	power_in	Ground reference for Isolator Side 1. Return for VDD1 and Side 1 I/O signals.
5	GND2	power_in	Ground reference for Isolator Side 2. Return for VDD2 and Side 2 I/O signals; isolated from GND1 by the internal capacitive barrier (3.0 kVrms for 1 min).
6	VOB	output	Logic Output B on Side 2. Digital output of the forward channel B driven by VIB. Drives CMOS levels referenced to VDD2/GND2; IOH/IOL rated ±6 mA.
7	VIA	input	Logic Input A on Side 2. CMOS digital input driving reverse channel A whose output (VOA) is on Side 1. VIH ≥ 0.7·VDD2, VIL ≤ 0.3·VDD2; input current ±10 µA max.
8	VDD2	power_in	Supply voltage for Isolator Side 2. Operating range 3.0 V to 5.5 V. Bypass to GND2 with a low-ESR ceramic capacitor (0.1 µF to 10 µF recommended).

Key specifications

Parameter	Value
Manufacturer	2Pai Semi
Package	SOIC-8-N
Category	Comm/UART
Pins	8

Ordering variants

π122E31
π122E31Q
π122E31π122E61
π122E31π122E61Q

CAD (KiCad official)

Symbol: π122E31
Footprint: Package_SO:SOIC-8_3.9x4.9mm_P1.27mm
3D model: SOIC-8-N (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`122e31.step`	122 KB	You want the bare part, or you mark your own boards.
`122e31-etched.step`	1.4 MB	You want the part with `122E31` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 359 faces against 147 in the bare model. It survives export, section views, and rendering in any CAD tool, and it drops straight into KiCad or Fusion with no extra setup.

Provenance

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

Datasheet: 2Pai Semi datasheet (18 pp, sha256 46f1f75769a4de29, retrieved 2026-08-17, tier: lcsc)
Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF