PCF8574RGYR

I/o Expanders Overview

The PCF8574RGYR is a remote 8-bit I/O expander for the I2C bus, manufactured by Texas Instruments. It operates within a supply voltage range of 2.5 V to 6 V and supports an I2C clock frequency up to 100 kHz. The device features eight quasi-bidirectional I/O pins (P0–P7) with latched outputs capable of directly driving LEDs. It includes an open-drain interrupt output (INT) triggered by input state changes. The component is housed in a 20-pin VQFN package measuring 4.5 mm × 3.5 mm. It functions across a temperature range of -40°C to +85°C with a maximum standby current of 10 μA.

I/o Expanders Feature Summary

• Provides general-purpose remote I/O expansion via the two-line bidirectional I2C interface.
• Features latched outputs with high-current drive capability suitable for directly driving LEDs.
• Includes an open-drain interrupt output that signals microcontrollers upon port input changes.

I/o Expanders Applications

• Telecom shelters including filter units
• Servers and routers for telecom switching equipment
• Personal computers and personal electronics
• Industrial automation systems
• Products with GPIO-limited processors

I/o Expanders Procurement Notes

Verify the specific ordering suffix RGYR against the manufacturer's official documentation to confirm the exact package type and reel specifications. Ensure compatibility with system voltage levels and I2C bus timing requirements before integration. Cross-reference the datasheet revision date to confirm technical accuracy.

I/o Expanders Selection Notes

Select this component when designing systems requiring additional digital inputs or outputs accessible via the I2C protocol. It is suitable for applications where minimizing microcontroller pin usage is critical. Verify that the required operating voltage falls within the 2.5 V to 6 V range and that the thermal characteristics of the VQFN package meet the design constraints.

I/o Expanders Part Context

The PCF8574 series consists of remote 8-bit I/O expanders designed for I2C bus communication. The PCF8574RGYR specifically denotes the version packaged in a 20-lead Very Thin Quad Flatpack No-Lead (VQFN) format. This family allows for efficient expansion of I/O capabilities in embedded systems without consuming valuable processor pins.

I/o Expanders Replacement Considerations

PCF8574APWR

I/o Expanders FAQ

How does the PCF8574 handle interrupt signaling?

The device generates an interrupt signal on the INT pin whenever there is a rising or falling edge on any port configured as an input. The interrupt circuit resets upon reading from or writing to the port that generated the interrupt.

What is the power-on reset behavior of the PCF8574?

Upon power-up, all I/Os are set to a high state. A power-on reset feature ensures the device returns to default conditions if the supply voltage drops below the POR threshold or experiences a glitch, provided the voltage cycle meets specified ramp rates.

Can the PCF8574 be used to drive LEDs directly?

Yes, the device features latched outputs with high-current drive capability, allowing it to directly drive LEDs. However, external current-limiting resistors are typically required depending on the LED specifications and supply voltage.