THVD1550DR from Texas Instruments, 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	R	output	Receive data output. Digital output that reflects the differential state of the A/B bus inputs when the receiver is enabled.
2	/RE	input	Receiver enable, active low. Has a 2 MΩ internal pull-up so the receiver defaults to disabled when the pin is left floating.
3	DE	input	Driver enable, active high. Has a 2 MΩ internal pull-down so the driver defaults to disabled (Hi-Z bus) when the pin is left floating.
4	D	input	Driver data input. Digital input whose logic level is transmitted differentially onto the A/B bus when the driver is enabled.
5	GND	power_in	Device ground reference (0 V).
6	A	bidirectional	RS-485 bus I/O port A (non-inverting, complementary to B). ±18-kV IEC 61000-4-2 ESD contact and ±25-kV air-gap protected differential bus line.
7	B	bidirectional	RS-485 bus I/O port B (inverting, complementary to A). ±18-kV IEC 61000-4-2 ESD contact and ±25-kV air-gap protected differential bus line.
8	VCC	power_in	5-V supply. Recommended operating range 4.5 V to 5.5 V. Bypass with a 100 nF ceramic capacitor to GND close to the pin.

Key specifications

Parameter	Value
Manufacturer	Texas Instruments
Package	SOIC-8
Category	Interface
Pins	8

Ordering variants

Same part, different packaging or reel option.

THVD1550DR
THVD1550DRD
THVD1550DRDGKR
THVD1550DRDGK

CAD (KiCad official)

Symbol: THVD1550DR
Footprint: Package_SO:SOIC-8_3.9x4.9mm_P1.27mm
3D model: SOIC-8 (KiCad packages3D, STEP)

Provenance

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

Datasheet: Texas Instruments datasheet (43 pp, sha256 6548e9b62323185e, retrieved 2026-08-17, tier: manufacturer)
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