This 8-bit input/output (I/O) expander for the two-line bidirectional bus (I2C) is designed for 2.5V to 6V VCC operation.
The PCF8574 device provides general-purpose remote I/O expansion for most microcontroller families by way of the I2C interface [serial clock (SCL), serial data (SDA)].
The device features an 8-bit quasi-bidirectional I/O port (P0–P7), including latched outputs with high-current drive capability for directly driving LEDs. Each quasi-bidirectional I/O can be used as an input or output without the use of a data-direction control signal. At power on, the I/Os are high. In this mode, only a current source to VCC is active.
| Top documentation | Type | Title | Format options | Date |
|---|---|---|---|---|
| * | Data sheet | PCF8574 Remote 8-Bit I/O Expander for I2 C Bus datasheet (Rev. K) | PDF | HTML | Sep 24, 2024 |
| Application note | Understanding Transient Drive Strength vs. DC Drive Strength in Level-Shifters (Rev. A) | PDF | HTML | Jul 3, 2024 | |
| 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 | |
| More literature | PCF8574 and PCF8574A Application Clip | Aug 18, 2004 | ||
| More literature | I2C Application Clip | Jul 19, 2004 | ||
| More literature | I2C and Serial Bus Devices Application Clip | Jul 10, 2003 | ||
| Application note | Improving System Interrupt Management Using the PCF8574 and PCF8574A I/O Expande | Jul 27, 2001 |
For additional terms or required resources, click any title below to view the detail page where available.
| Package | Pins | CAD symbols, footprints & 3D models |
|---|---|---|
| PDIP (N) | 16 | Ultra Librarian |
| TSSOP (PW) | 20 | Ultra Librarian |
| TVSOP (DGV) | 20 | Ultra Librarian |
| VQFN (RGY) | 20 | Ultra Librarian |
| SOIC (DW) | 16 | Ultra Librarian |
| VQFN (RGT) | 16 | Ultra Librarian |
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