2-Bit Bidirectional I2C Bus and SMBus Voltage-Level Shifter

2-Bit Bidirectional I2C Bus and SMBus Voltage-Level Shifter - PCA9306


The PCA9306 device is a dual bidirectional I2C and SMBus voltage-level translator with an enable (EN) input, and is operational from 1.2-V to 3.3-V VREF1 and 1.8-V to 5.5-V VREF2.

The PCA9306 device allows bidirectional voltage translations between 1.2 V and 5 V, without the use of a direction pin. The low ON-state resistance (RON) of the switch allows connections to be made with minimal propagation delay. When EN is high, the translator switch is ON, and the SCL1 and SDA1 I/O are connected to the SCL2 and SDA2 I/O, respectively, allowing bidirectional data flow between ports. When EN is low, the translator switch is off, and a high-impedance state exists between ports.

In addition to voltage translation, the PCA9306 device can be used to isolate a 400-kHz bus from a 100-kHz busby controlling the EN pin, and disconnecting the slower bus during fast-mode communication.


  • 2-Bit Bidirectional Translator for SDA and SCL
    Lines in Mixed-Mode I2C Applications
  • I2C and SMBus Compatible
  • Less Than 1.5-ns Maximum Propagation Delay to
    Accommodate Standard-Mode and Fast-Mode I2C
    Devices and Multiple Masters
  • Allows Voltage-Level Translation Between
    • 1.2-V VREF1 and 1.8-V, 2.5-V, 3.3-V,
      or 5-V VREF2
    • 1.8-V VREF1 and 2.5-V, 3.3-V,
      or 5-V VREF2
    • 2.5-V VREF1 and 3.3-V or 5-V VREF2
    • 3.3-V VREF1 and 5-V VREF2
  • Provides Bidirectional Voltage Translation With No
    Direction Pin
  • Low 3.5-Ω ON-State Resistance Between Input
    and Output Ports Provides Less Signal Distortion
  • Open-Drain I2C I/O Ports (SCL1, SDA1, SCL2,
    and SDA2)
  • 5-V Tolerant I2C I/O Ports to Support Mixed-Mode
    Signal Operation
  • High-Impedance SCL1, SDA1, SCL2, and SDA2
    Pins for EN = Low
  • Lockup-Free Operation for Isolation When
    EN = Low
  • Flow-Through Pinout for Ease of Printed-Circuit-
    Board Trace Routing
  • Latch-Up Performance Exceeds 100 mA Per
    JESD 78, Class II
  • ESD Protection Exceeds JESD 22
    • 2000-V Human-Body Model (A114-A)
    • 1000-V Charged-Device Model (C101)
    • I2C, SMBus, PMBus, MDIO, UART, Low-Speed
      SDIO, GPIO, and Other Two-Signal Interfaces
    • Servers
    • Routers (Telecom Switching Equipment)
    • Personal Computers
    • Industrial Automation

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Parametrics Compare all products in I2C Level Shifters, Buffers, and Hubs

Number of Outputs
fSCLK (Max) (MHz)
VCC (Max) (V)
VCC (Min) (V)
Frequency (Max) (kHz)
Channel Width
Master Side I2C Bus Capacitance Supported (pF)
Slave Side I2C Bus Capacitance Supported (pF)
Operating Temperature Range (C)
Package Group
PCA9306 PCA9306-Q1 TCA9406
2    2    2   
0.4    0.4    1   
5.5    5.5    5.5   
1.2    1.2    1.65   
400    400    1000   
2    2    2   
400    400    400   
400    400    400   
5V Tolerant I/O
Enable Pin
Low Voltage
Open-Drain I/O Type   
5V Tolerant I/O
Enable Pin
Low Voltage
Open-Drain I/O Type   
5V Tolerant I/O
Enable Pin
Open-Drain I/O Type   
-40 to 85    -40 to 105
-40 to 85   
-40 to 85   

Other qualified versions of PCA9306

Version Part Number Definition
Automotive PCA9306-Q1 Q100 devices qualified for high-reliability automotive applications targeting zero defects