SIT3490EEUA from SIT, in a MSOP-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, 3.0 V to 5.5 V nominal (absolute max +7 V). Bypass locally with a 0.1 uF ceramic capacitor to GND.
2	RO	output	Receiver output (CMOS logic). RO is high when A-B >= +200 mV and low when A-B <= -200 mV. Drives VOH >= VCC-1.5 V at IOUT = -4 mA and VOL <= 0.4 V at IOUT = +4 mA.
3	DI	input	Driver input (CMOS logic, VIH >= 2.0 V, VIL <= 0.8 V). A low on DI forces output Y low and Z high; a high on DI forces Y high and Z low.
4	GND	power_in	Ground reference for supply and all signals.
5	Y	output	Non-inverting driver output. Connect to the RS-485/RS-422 differential bus. Driver has short-circuit current limiting (35 mA to 250 mA to 0-12 V and -35 mA to -250 mA to -7-0 V) and ±15 kV HBM ESD protection.
6	Z	output	Inverting driver output. Connect to the RS-485/RS-422 differential bus opposite polarity from Y. ±15 kV HBM ESD protected.
7	B	input	Inverting receiver input from the RS-485/RS-422 differential bus. 1/8 unit-load (RIN >= 96 kΩ); tolerates -7 V to +12 V common-mode. ±15 kV HBM ESD protected.
8	A	input	Non-inverting receiver input from the RS-485/RS-422 differential bus. 1/8 unit-load (RIN >= 96 kΩ); tolerates -7 V to +12 V common-mode. ±15 kV HBM ESD protected.

Key specifications

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

Ordering variants

Same part, different packaging or reel option.

SIT3490EEUA
SIT3490EEUAEESA
SIT3490EEUAEEPA

CAD (KiCad official)

Symbol: SIT3490EEUA
Footprint: Package_SO:MSOP-8_3x3mm_P0.65mm
3D model: MSOP-8 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`sit3490eeua.step`	123 KB	You want the bare part, or you mark your own boards.
`sit3490eeua-etched.step`	2.3 MB	You want the part with `SIT3490EEUA` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 565 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