PCA8574APW,112

I/o Expanders Overview

The PCA8574APW,112 is a remote 8-bit I/O expander for the I2C-bus manufactured by NXP Semiconductors. It operates within a supply voltage range of 2.3 V to 5.5 V and supports I2C bus frequencies up to 400 kHz. The device features eight quasi-bidirectional ports with latched outputs capable of sinking 25 mA per bit and a total package sink capability of 200 mA. It includes an active LOW open-drain interrupt output (INT) and three hardware address inputs (A0, A1, A2) allowing for eight programmable slave addresses. The typical standby current is 4.5 µA, and it functions in temperatures from -40 °C to +85 °C. The component is housed in a TSSOP16 plastic thin shrink small outline package.

I/o Expanders Feature Summary

• Provides general-purpose remote I/O expansion via a two-wire bidirectional I2C-bus interface.
• Features eight quasi-bidirectional ports that default to inputs at power-up with weak internal pull-ups.
• Includes an active LOW open-drain interrupt output to notify microcontrollers of input state changes without polling.
• Offers low standby current consumption suitable for mobile applications.

I/o Expanders Applications

• LED signs and displays
• Key pads
• Industrial control systems
• Medical equipment
• PLCs

I/o Expanders Procurement Notes

Verify the specific ordering suffix ',112' corresponds to the tube packing method as defined in the official datasheet. Confirm the manufacturer is NXP Semiconductors. Ensure the part number matches the TSSOP16 package variant. Check for RoHS compliance status if required by your project specifications. Validate the operating temperature range against your environmental requirements.

I/o Expanders Selection Notes

Select this component when an I2C-based solution is required to expand GPIO capabilities on a microcontroller system. It is suitable for applications needing direct LED driving due to its high sink current capability. Consider the fixed slave address map distinct from the PCF8574 series to avoid bus conflicts. Evaluate the need for interrupt-driven input monitoring versus continuous polling.

I/o Expanders Part Context

This component belongs to the PCA8574/PCA8574A family of remote I/O expanders. It serves as a drop-in replacement for the PCF8574T/3 and PCF8574AT/3 series, offering improved performance characteristics such as higher bus speed and greater drive current. The 'A' designation indicates a different fixed portion of the slave address compared to the non-'A' version.

I/o Expanders Replacement Considerations

The PCA8574D is a drop-in replacement for the PCF8574T/3. The PCA8574AD replaces the PCF8574AT/3. The PCA8574TS replaces the PCF8574TS/3. The PCA8574ATS replaces the PCF8574ATS/3. These replacements offer migration paths from older PCF series devices.

I/o Expanders FAQ

How does the PCA8574 differ from the PCF8574?

The PCA8574 and PCF8574 are functionally identical but have different fixed portions of their slave addresses. This allows both types to coexist on the same I2C bus without address conflict. The PCA8574 also offers a wider voltage range and higher drive current.

What is the purpose of the INT pin?

The INT pin is an active LOW open-drain output that signals the microcontroller when any input port state differs from its corresponding register state. This allows the MCU to detect input changes without continuously polling the I2C bus.

Can multiple PCA8574 devices be used on the same bus?

Yes, up to eight PCA8574 devices and eight PCA8574A devices can be used on the same I2C bus, supporting up to 16 devices total or 128 I/Os, by configuring the three hardware address pins (A0, A1, A2).