BL3085A from BL Shanghai Belling, 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	RO	output	Receiver Output. CMOS output driven from the differential A/B receiver comparator. High-Z when the receiver is disabled (/RE=1). VOH >= 4.0V at IO=8mA (5V), VOL <= 0.4V at IO=8mA.
2	/RE	input	Receiver Output Enable (active low). /RE=0 enables the receiver; /RE=1 disables (RO High-Z). With /RE=1 and DE=0 the device enters shutdown mode (ICC <= 10 uA).
3	DE	input	Driver Output Enable (active high). DE=1 enables the differential driver on A/B; DE=0 places A/B in High-Z. With /RE=1 and DE=0 the device enters shutdown mode.
4	DI	input	Driver Input. CMOS logic input driving the differential A/B outputs when DE=1 (DI=1 -> A=high, B=low). Input hysteresis typ. 100 mV; VIH >= 2.0V, VIL <= 0.8V.
5	GND	power_in	Ground reference for the device. All voltages are referred to this pin.
6	A	bidirectional	Non-inverting receiver input and non-inverting driver output (RS-485 bus line A). Withstands +/-13V bus voltage; receiver input resistance >= 96 kOhm (1/8 unit load). Differential threshold VTH between -200 mV and -50 mV.
7	B	bidirectional	Inverting receiver input and inverting driver output (RS-485 bus line B). Withstands +/-13V bus voltage; +/-15 kV IEC 61000-4-2 contact ESD protection.
8	VCC	power_in	Power supply input. Operating range +3.0V to +3.6V (3.3V option) or +4.5V to +5.5V (5V option); absolute max +7V. Typical ICC ~350 uA (5V) / ~270 uA (3.3V), shutdown ICC <= 10 uA. Bypass with 0.1 uF to GND.

Key specifications

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

Ordering variants

Same part, different packaging or reel option.

BL3085A(H)

CAD (KiCad official)

Symbol: BL3085A
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
`bl3085a.step`	122 KB	You want the bare part, or you mark your own boards.
`bl3085a-etched.step`	1.9 MB	You want the part with `BL3085A` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 459 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 (11 pp, sha256 c911764fb5bb997a, 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