The PCA9554A open-drain interrupt ( INT) output is activated when any input state differs from its corresponding Input Port register state and is used to indicate to the system master that an input state has changed.
INT can be connected to the interrupt input of a microcontroller. By sending an interrupt signal on this line, the remote I/O can inform the microcontroller if there is incoming data on its ports without having to communicate via the I2C bus. Thus, the PCA9554A can remain a simple slave device.
The device’s outputs (latched) have high-current drive capability for directly driving LEDs and low current consumption.
Three hardware pins (A0, A1, and A2) are used to program and vary the fixed I2C address and allow up to eight devices to share the same I2C bus or SMBus.
The PCA9554A is pin-to-pin and I2C address compatible with the PCF8574A. However, software changes are required, due to the enhancements in the PCA9554A over the PCF8574A.
The PCA9554A and PCA9554 are identical except for their fixed I2C address. This allows for up to 16 of these devices (8 of each) on the same I2C/SMBus.
| Type | Title | Date | ||
|---|---|---|---|---|
| * | Data sheet | PCA9554A Remote 8-Bit I2C and SMBus I/O Expander With Interrupt Output and Configuration Registers datasheet (Rev. F) | PDF | HTML | 12 Mar 2021 |
| Application note | I2C Dynamic Addressing | 25 Apr 2019 | ||
| Selection guide | Logic Guide (Rev. AB) | 12 Jun 2017 | ||
| Application note | Choosing the Correct I2C Device for New Designs | PDF | HTML | 07 Sep 2016 | |
| Application note | Understanding and Interpreting Standard-Logic Data Sheets (Rev. C) | 02 Dec 2015 | ||
| Application note | Understanding the I2C Bus | PDF | HTML | 30 Jun 2015 | |
| Application note | Maximum Clock Frequency of I2C Bus Using Repeaters | 15 May 2015 | ||
| Application note | I2C Bus Pull-Up Resistor Calculation | PDF | HTML | 13 Feb 2015 | |
| Application note | Programming Fun Lights With TI's TCA6507 | 30 Nov 2007 | ||
| Application note | Semiconductor Packing Material Electrostatic Discharge (ESD) Protection | 08 Jul 2004 |
For additional terms or required resources, click any title below to view the detail page where available.
| Package | Pins | Download |
|---|---|---|
| SOIC (DW) | 16 | View options |
| SSOP (DB) | 16 | View options |
| SSOP (DBQ) | 16 | View options |
| TSSOP (PW) | 16 | View options |
| TVSOP (DGV) | 16 | View options |
| VQFN (RGT) | 16 | View options |
| VQFN (RGV) | 16 | View options |
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