Translates the two lines of an I2C or SMBus bus between a lower and a higher voltage domain, so a 1.8 or 3.3 V controller talks to 5 V devices on the same bus. Each channel is a pass transistor with no direction control, so it handles the open-drain, bidirectional traffic automatically, and the two VREF pins set the levels for each side. An EN pin isolates the buses when low. A tiny, standard fix for mixed-voltage I2C.

Pinout

Pin	Name	Type	Function
1	GND	power_in	Ground, 0 V reference for the device.
2	VREF1	power_in	Low-voltage-side reference supply voltage for SCL1 and SDA1. Recommended operating range 0 V to 5.5 V; supports translation from 1.2 V up to (VREF2 - 0.6 V).
3	SCL1	bidirectional	Serial clock, low-voltage side. Open-drain I2C/SMBus clock line referenced to VREF1. High-impedance when EN is low.
4	SDA1	bidirectional	Serial data, low-voltage side. Open-drain I2C/SMBus data line referenced to VREF1. High-impedance when EN is low.
5	SDA2	bidirectional	Serial data, high-voltage side. Open-drain I2C/SMBus data line referenced to VREF2. High-impedance when EN is low.
6	SCL2	bidirectional	Serial clock, high-voltage side. Open-drain I2C/SMBus clock line referenced to VREF2. High-impedance when EN is low.
7	VREF2	power_in	High-voltage-side reference supply voltage for SCL2 and SDA2. Recommended operating range 0 V to 5.5 V; must be between VREF1 + 0.6 V and 5.5 V for translation.
8	EN	input	Switch enable input. When high, the translator switch is ON and SCL1/SDA1 connect to SCL2/SDA2. When low, the switch is off and all I/Os are high-impedance (also isolates the bus, e.g. a 400-kHz bus from a 100-kHz bus).

Key specifications

Parameter	Value
Type	Dual bidirectional I2C/SMBus level translator
Low side	1.0-3.6 V
High side	1.8-5.5 V
Channels	2 (SCL, SDA)
Direction control	None (pass-transistor)
Enable	EN pin isolates buses
Package	VSSOP-8

Ordering variants

Same part, different packaging or reel option.

PCA9306DCUR (VSSOP-8, tape & reel)
PCA9306DCUT (VSSOP-8, small reel)
PCA9306DQER (X2SON-8)

CAD (KiCad official)

Symbol: Interface:PCA9306 (KiCad official)
Footprint: Package_SO:VSSOP-8_2.3x2mm_P0.5mm
3D model: VSSOP-8 (KiCad packages3D, STEP)

Provenance

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

Datasheet: Texas Instruments datasheet (38 pp, sha256 1cd97c734729f2bf, 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