TCA4307DGKR from Texas Instruments, 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	EN	input	Active-high chip enable. When low, the device enters low-current mode, disables rise-time accelerators and pre-charge, drives READY low, and isolates SDAIN/SCLIN from SDAOUT/SCLOUT. Tie to VCC for normal operation if not used. VIH >= 0.7VCC, VIL <= 0.3VCC.
2	SCLOUT	bidirectional	Serial clock output to the card-side I2C bus. Open-drain, requires a pull-up resistor. Isolated from SCLIN until EN is high and start-up is complete.
3	SCLIN	bidirectional	Serial clock input from the backplane-side I2C bus. Open-drain, requires a pull-up resistor. Pre-charged to 1 V during insertion to minimize glitching.
4	GND	power_in	Device ground reference.
5	READY	output	Open-drain connection flag / rise-time accelerator control. Low when EN is low or during start-up; goes high when EN is high, start-up is complete, and the two bus sides are connected. Connect a ~10 kOhm pull-up to VCC. IOL = 3 mA, VOL <= 0.4 V.
6	SDAIN	bidirectional	Serial data input from the backplane-side I2C bus. Open-drain, requires a pull-up resistor. Pre-charged to 1 V during live insertion.
7	SDAOUT	bidirectional	Serial data output to the card-side I2C bus. Open-drain, requires a pull-up resistor. Isolated from SDAIN until EN is high and start-up is complete.
8	VCC	power_in	Main input supply from the backplane, 2.3 V to 5.5 V. Sets the supply voltage for the backplane-side I2C devices and the internal pull-ups from SDAOUT/SCLOUT. Place a 0.1 uF bypass capacitor close to this pin.

Key specifications

Parameter	Value
Manufacturer	Texas Instruments
Package	MSOP-8
Category	Comm/UART
Pins	8

Ordering variants

Same part, different packaging or reel option.

TCA4307DGKR
TCA4307DGKRDGKT
TCA4307DGKRDRGR
TCA4307DGKRDRGT

CAD (KiCad official)

Symbol: TCA4307DGKR
Footprint: Package_SO:MSOP-8_3x3mm_P0.65mm
3D model: MSOP-8 (KiCad packages3D, STEP)

Provenance

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

Datasheet: Texas Instruments datasheet (29 pp, sha256 904278fd916371ef, 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