NXP's GPIO expanders are a simple, cost-effective way to monitor and control several peripheral signals. They make it easy for designers to add extra I/O to their design and thereby free up the microprocessor's GPIO for other, more important functions. NXP is the industry leader in serial-interface GPIO expanders, and offers a broad selection of cost-effective, easy-to-use options. NXP's I2C-bus GPIO expanders support three operating modes for data transfer: Standard Mode, with data transfer rates from 0 kbps to 100 kbps, Fast Mode (Fm), with data transfer rates from 0 kbps to 400 kbps, and Fast-mode Plus (Fm+) with data rates from 0 kbps to 1 Mbps. Since the newer Fm+ GPIO are backward compatible all the way back to Standard Mode, it's easy to expand existing designs without changing the bus master device.
NXP offers a broad portfolio of I²C‑bus GPIO expanders that provide cost‑effective, flexible I/O expansion for designers. The document lists the available devices (e.g., PCA8574, PCF8575, PCA9558) and describes their operating modes, including Standard, Fast and Fast‑mode Plus, which support up to 1 Mbps.
The expanders are grouped by output structure—totem‑pole, quasi‑bidirectional and open‑drain—each with distinct electrical characteristics such as voltage tolerance, standby current and maximum drive current. Evaluation modules and development kits are also mentioned for rapid prototyping.
| Operating Voltage Range | 2.3 V – 5.5 V |
|---|---|
| Standby Current | 0.25 pA (typical) |
| Maximum Output Drive Current | 25 mA per pin |
| Number of Device Addresses | 64 |
Up to 64 device addresses are available on the I²C bus.
Each pin can source or sink up to 25 mA.