SIT3490EESA from SIT, in a SOP-8. 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	VCC	power_in	Positive supply input. Operating range 3.0V to 5.5V (absolute max +7V). Typical supply current ICC = 240µA (max 400µA). Bypass locally to GND.
2	RO	output	Receiver output (CMOS logic). RO is high when A−B ≥ +200mV and low when A−B ≤ −200mV. VOH ≥ VCC−1.5V at −4mA; VOL ≤ 0.4V at +4mA.
3	DI	input	Driver input (CMOS logic). A low on DI forces Y low and Z high; a high on DI forces Y high and Z low. VIH ≥ 2.0V, VIL ≤ 0.8V, input leakage ±2µA.
4	GND	power_in	Device ground. Reference for all voltages on the part.
5	Y	output	Non-inverting differential driver output to the RS-485/RS-422 bus. Differential swing VOD ≥ 1.5V into RL = 54Ω. ±15kV HBM ESD protected. Includes short-circuit and over-voltage protection.
6	Z	output	Inverting differential driver output to the RS-485/RS-422 bus. Complementary to Y. ±15kV HBM ESD protected; short-circuit and over-voltage protected.
7	B	input	Inverting differential receiver input from the RS-485/RS-422 bus. 1/8 unit-load, RIN ≈ 96kΩ. Common-mode range −7V to +12V. ±15kV HBM ESD.
8	A	input	Non-inverting differential receiver input from the RS-485/RS-422 bus. 1/8 unit-load, RIN ≈ 96kΩ. Common-mode range −7V to +12V. ±15kV HBM ESD.

Key specifications

Parameter	Value
Manufacturer	SIT
Package	SOP-8
Category	Interface
Pins	8

Ordering variants

Same part, different packaging or reel option.

SIT3490EESA
SIT3490EESAEEPA
SIT3490EESAEEUA

CAD (KiCad official)

Symbol: SIT3490EESA
Footprint: Package_SO:SOIC-8_3.9x4.9mm_P1.27mm
3D model: SOP-8 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`sit3490eesa.step`	122 KB	You want the bare part, or you mark your own boards.
`sit3490eesa-etched.step`	2.3 MB	You want the part with `SIT3490EESA` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 577 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: SIT datasheet (13 pp, sha256 4e2651818bcb1ad0, 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