PCF8574NE4

I/o Expanders Overview

The PCF8574NE4 is an 8-bit I/O expander for the I2C bus, manufactured by Texas Instruments. It operates within a supply voltage range of 2.5V to 6V and supports a maximum clock frequency of 100 kHz. The device features an 8-bit quasi-bidirectional I/O port (P0–P7) with latched outputs capable of driving LEDs directly. It includes an open-drain interrupt output (INT) that triggers on any rising or falling edge of the port inputs. The component is housed in a 16-pin PDIP package and functions across an operating temperature range of -40°C to 85°C.

I/o Expanders Feature Summary

• Provides remote I/O expansion via a two-line bidirectional I2C interface
• Features latched outputs with high-current drive capability for direct LED driving
• Includes an open-drain interrupt output triggered by input state changes
• Compatible with most microcontroller families without data-direction control signals

I/o Expanders Applications

• Telecom shelters: filter units
• Servers and routers
• Personal computers and electronics
• Industrial automation systems
• Products with GPIO-limited processors

I/o Expanders Procurement Notes

Verify the specific ordering suffix NE4 corresponds to the 16-pin PDIP package variant when sourcing. Confirm compliance with RoHS standards and lead time requirements through authorized distributors. Ensure the procurement documentation matches the Texas Instruments part number exactly to avoid confusion with other package types like SOIC or TSSOP.

I/o Expanders Selection Notes

Select this component when system design requires expanding general-purpose I/O lines using the I2C protocol. It is suitable for applications needing low standby current consumption and compatibility with 3.3V or 5V logic levels. Consider the 16-pin PDIP package if through-hole mounting is required for prototyping or specific mechanical constraints.

I/o Expanders Part Context

The PCF8574NE4 belongs to the PCF8574 family of remote 8-bit I/O expanders. This series is designed to address GPIO limitations in microcontrollers by providing additional input and output ports over the I2C bus. The NE4 suffix specifically denotes the PDIP package version, distinguishing it from surface-mount alternatives such as SOIC or VQFN packages available within the same product line.

I/o Expanders Replacement Considerations

PCF8574N

I/o Expanders FAQ

How does the PCF8574 handle input/output direction configuration?

The PCF8574 uses a quasi-bidirectional design where each I/O pin can function as an input or output without a dedicated direction control signal. Writing a '1' configures the pin as an input (high impedance), while writing a '0' configures it as an output.

What is the purpose of the INT pin on the PCF8574?

The INT pin provides an open-drain interrupt output. It is activated whenever there is a rising or falling edge on any of the port inputs configured as inputs, allowing the microcontroller to respond to external events without continuous polling.

Can the PCF8574 directly drive LEDs?

Yes, the PCF8574 features latched outputs with high-current drive capability, allowing it to directly drive LEDs without additional driver circuits, provided the current limits specified in the datasheet are not exceeded.