PCF8574AT/3,512

I/o Expanders Overview

The PCF8574AT/3,512 is an NXP remote 8-bit I/O expander for the I2C-bus with interrupt. It provides general-purpose remote I/O expansion via a two-wire bidirectional I2C-bus interface operating at 100 kHz. The device features eight quasi-bidirectional ports (P0–P7) that default to inputs at power-up and can be independently assigned as inputs or outputs without direction control signals. It operates on a supply voltage of 2.5 V to 6 V with a typical standby current of 2.5 µA. The package is SO16, and it supports an operating temperature range from -40 °C to +85 °C.

I/o Expanders Feature Summary

• I2C-bus to parallel port expander
• Active LOW open-drain interrupt output
• Latched outputs directly drive LEDs
• Eight programmable slave addresses using three address pins

I/o Expanders Applications

• LED signs and displays
• Key pads
• Industrial control
• Medical equipment
• PLC

I/o Expanders Procurement Notes

Verify the specific ordering suffix /3,512 against the manufacturer's official documentation to confirm the packing method and tube dry pack specifications. Ensure the component matches the standard marking requirements for the SO16 package version listed in the datasheet. Cross-reference the part number with authorized distributors to confirm availability and authenticity before procurement.

I/o Expanders Selection Notes

Select this component when a microcontroller requires additional I/O lines via a standard I2C interface. It is suitable for applications needing low standby current and direct LED driving capabilities. Consider the SO16 package constraints and the requirement for external pull-up resistors on the SDA and SCL lines. Verify that the 100 kHz bus speed meets the system timing requirements.

I/o Expanders Part Context

The PCF8574AT/3,512 belongs to the PCF8574 family of remote I/O expanders. It is functionally identical to the PCF8574A series but utilizes a different fixed portion of the slave address, allowing both types to coexist on the same I2C bus. This family is designed for expanding GPIO resources in embedded systems where pin count is limited.

I/o Expanders Replacement Considerations

PCA9674 is a drop-in replacement offering higher I2C frequency and increased sink current. PCA8574 provides similar functionality with a wider voltage range. Check migration path tables for compatibility regarding address mapping and interrupt handling.