BL3085B from BL Shanghai Belling, in a SOIC-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	RO	output	Receiver Output. Outputs logic high when A-B differential input is greater than +200mV; outputs logic low when less than -200mV. High-impedance when /RE is high.
2	/RE	input	Receiver Output Enable, active low. When low, the receiver output RO is enabled; when high, RO is high-impedance.
3	DE	input	Driver Output Enable, active high. When high, the differential driver outputs A and B are enabled; when low, the driver outputs are high-impedance.
4	DI	input	Driver Input. Logic input to the differential driver. A logic low forces A low and B high; a logic high forces A high and B low.
5	GND	power_in	Ground reference (0 V) for supply and I/O signals.
6	A	bidirectional	Non-inverting driver output and non-inverting receiver input for the RS-485/RS-422 differential bus.
7	B	bidirectional	Inverting driver output and inverting receiver input for the RS-485/RS-422 differential bus.
8	VCC	power_in	Positive supply voltage input, 4.75V to 5.25V (5V nominal). Bypass to GND with a 0.1µF capacitor close to the pin.

Key specifications

Parameter	Value
Manufacturer	BL Shanghai Belling
Package	SOIC-8
Category	Interface
Pins	8

Ordering variants

BL3085BSOP-8

CAD (KiCad official)

Symbol: BL3085B
Footprint: Package_SO:SOIC-8_3.9x4.9mm_P1.27mm
3D model: SOIC-8 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`bl3085b.step`	122 KB	You want the bare part, or you mark your own boards.
`bl3085b-etched.step`	2.0 MB	You want the part with `BL3085B` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 488 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: BL Shanghai Belling datasheet (8 pp, sha256 1079f010a53bee3f, 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