4-Channel I2C And SMBus Multiplexer With Interrupt Logic - PCA9544A


4-Channel I2C And SMBus Multiplexer With Interrupt Logic


Recommended alternative parts

  • TCA9544A  - The device has the SAME FUNCTIONALITY and PINOUT as the compared device but is NOT an exact equivalent.   TCA9544A is an enhanced version of the PCA9544A with an extended supply voltage range and performance enhancements related to Power-On Reset.


The PCA9544A is a quad bidirectional translating switch controlled via the I2C bus. The SCL/SDA upstream pair fans out to four downstream pairs, or channels. One SCL/SDA pair can be selected at a time, and this is determined by the contents of the programmable control register. Four interrupt inputs (INT3INT0), one for each of the downstream pairs, are provided. One interrupt output (INT) acts as an AND of the four interrupt inputs.

A power-on reset function puts the registers in their default state and initializes the I2C state machine, with no channel selected.

The pass gates of the switches are constructed such that the VCC pin can be used to limit the maximum high voltage, which will be passed by the PCA9544A. This allows the use of different bus voltages on each pair, so that 1.8-V, 2.5-V, or 3.3-V parts can communicate with 5-V parts, without any additional protection. External pull-up resistors pull the bus up to the desired voltage level for each channel. All I/O pins are 5-V tolerant.

For all available packages, see the orderable addendum at the end of the data sheet.


  • 1-of-4 Bidirectional Translating Switches
  • I2C Bus and SMBus Compatible
  • Four Active-Low Interrupt Inputs
  • Active-Low Interrupt Output
  • Three Address Pins, Allowing up to Eight Devices on the I2C Bus
  • Channel Selection Via I2C Bus
  • Power Up With All Switch Channels Deselected
  • Low RON Switches
  • Allows Voltage-Level Translation Between 1.8-V, 2.5-V, 3.3-V, and 5-V Buses
  • No Glitch on Power Up
  • Supports Hot Insertion
  • Low Standby Current
  • Operating Power-Supply Voltage Range of 2.3 V to 5.5 V
  • 5.5-V Tolerant Inputs
  • 0 to 400-kHz Clock Frequency
  • Latch-Up Performance Exceeds 100 mA Per JESD 78
  • ESD Protection Exceeds JESD 22
    • 2000-V Human-Body Model (A114-A)
    • 200-V Machine Model (A115-A)
    • 1000-V Charged-Device Model (C101)

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Parametrics Compare all products in I2C Multiplexer, Switch

tpd max (ns)
Operating Temperature Range (C)
Max Frequency (kHz)
I2C Address
Channel Width
Simultaneously Active Channels
Special Features
PCA9544A PCA9545A
1    1   
-40 to 85    -40 to 85   
400    400   
1110 xxx    1110 0xx   
4    4   
1    1 to 4   
Interrupt Output
5V Tolerant I/O   
Interrupt Output
Reset Input
5V Tolerant I/O