TCA9509DGKR from Texas Instruments, in a VSSOP-8-0.65mm. 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	VCCA	power_in	A-side supply voltage (0.9 V to 5.5 V). Sets the low-voltage side reference for the internal buffer; no external pullups required on A-side.
2	SCLA	bidirectional	Serial clock bus, A side. Open-drain I2C clock line referenced to VCCA (0.9 V to 5.5 V). A-side uses internal 1 mA current source pull-up and 200 Ω pull-down driver.
3	SDAA	bidirectional	Serial data bus, A side. Open-drain I2C data line referenced to VCCA (0.9 V to 5.5 V). No external pull-up required on A-side.
4	GND	power_in	Supply ground reference for the device.
5	EN	input	Active-high repeater enable input. Drivers are disabled when EN is low; state should only change when both bus sides are idle. VIH >= 0.7 x VCCA, VIL <= 0.3 x VCCA.
6	SDAB	bidirectional	Serial data bus, B side. Open-drain SMBus/I2C data line; connect to VCCB through an external pull-up resistor (typ. 10 kΩ). Supports up to 400 pF bus capacitance.
7	SCLB	bidirectional	Serial clock bus, B side. Open-drain SMBus/I2C clock line; connect to VCCB through an external pull-up resistor (typ. 10 kΩ).
8	VCCB	power_in	B-side and device supply voltage (2.7 V to 5.5 V). Drivers are not enabled unless VCCB > 2.5 V and VCCA > 0.8 V.

Key specifications

Parameter	Value
Manufacturer	Texas Instruments
Package	VSSOP-8-0.65mm
Category	Interface
Pins	8

Ordering variants

Same part, different packaging or reel option.

TCA9509DGKR
TCA9509DGKRRVHR
TCA9509DGKRRVH

CAD (KiCad official)

Symbol: TCA9509DGKR
Footprint: Package_SO:VSSOP-8_2.3x2mm_P0.5mm
3D model: VSSOP-8-0.65mm (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`tca9509dgkr.step`	122 KB	You want the bare part, or you mark your own boards.
`tca9509dgkr-etched.step`	2.4 MB	You want the part with `TCA9509DGKR` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 581 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: Texas Instruments datasheet (28 pp, sha256 c74926d43228afe4, 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