The PCA9544A is a 4-channel, bidirectional translating multiplexer 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 ( INT3– INT0), 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.
| Top documentation | Type | Title | Format options | Date |
|---|---|---|---|---|
| * | Data sheet | PCA9544A Low Voltage 4-Channel I2C and SMBus Multiplexer With Interrupt Logic datasheet (Rev. G) | PDF | HTML | Mar 11, 2021 |
| Application note | I2C Solutions for Hot Swap Applications (Rev. A) | Jan 31, 2023 | ||
| Application note | I2C Dynamic Addressing | Apr 25, 2019 | ||
| Application note | Choosing the Correct I2C Device for New Designs | PDF | HTML | Sep 7, 2016 | |
| Application note | Understanding the I2C Bus | PDF | HTML | Jun 30, 2015 | |
| Application note | Maximum Clock Frequency of I2C Bus Using Repeaters | May 15, 2015 | ||
| Application note | I2C Bus Pull-Up Resistor Calculation | PDF | HTML | Feb 13, 2015 | |
| Application note | Troubleshooting I2C Bus Protocol | Oct 19, 2009 |
For additional terms or required resources, click any title below to view the detail page where available.
| Package | Pins | CAD symbols, footprints & 3D models |
|---|---|---|
| TSSOP (PW) | 20 | Ultra Librarian |
| TVSOP (DGV) | 20 | Ultra Librarian |
| SOIC (DW) | 20 | Ultra Librarian |
| VQFN (RGY) | 20 | Ultra Librarian |
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