Compact PCF8574A I2C Open-Collector Board V2

*The RoHS icon on this product indicates that the PCBs, components, solder, and chemicals are all lead-free and RoHS compliant. Additionally, this product is produced using a lead-free process. Unfortunately, we are currently unable to provide documentation confirming that this product is RoHS compliant.

Resources:

• User Manual (.pdf)
• Schematic (.pdf)
• PCF8574 Datasheet (.pdf)
• 3D Models (.step)

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Package Includes:

• 1x Board

This package does not include Din-Rail PCB holders and cables.

Notes:

• This board uses 4-pin, 2.0mm pin pitch connectors for I2C bus.

Features:

• PCF8574A I2C bus I/O expander
• 8 open-collector outputs
• Operating voltage: 2.5Vdc to 5.5Vdc
• On-board reverse polarity protection circuit
• 100kHz I2C Bus frequency
• Address selection via 3 jumpers(supports up to 8 addresses)
• Support up to 16 boards on a single I2C bus
• Compatible with most microcontrollers
• Maximum load voltage: 50Vdc
• Rated Collector Current: 500mA (using a single output)
• PCB dimensions: 67 x 27 mm

This is an I2C bus output board designed as a remote 8-output expander via the I2C bus, based on the PCF8574A, making it an ideal open-collector expander for the I2C bus. The board is designed to be compatible with most microcontrollers.

The PCF8574A is an I2C bus controller that communicates with a microcontroller and receives commands to control the output ports. It supports a 100kHz I2C bus frequency and can be connected to the I2C port of most microcontrollers.

For output driving, the board uses the ULN2803A, which provides 8 open-collector outputs. Each output can handle a maximum current of 500mA (when using a single output) and a voltage of up to 50V.

The board's address is set using three jumpers, allowing up to 8 different addresses, so 8 boards can be connected on the same I2C bus. Additionally, 16 boards can be connected on a single bus by using 8 boards with PCF8574 and 8 boards with PCF8574A, as these two ICs have different address ranges.

The board includes a reverse polarity protection circuit to prevent damage from incorrect power supply connections.

Difference Between I2C-OC805SAV2 and I2C-OC805SV2
The I2C-OC805SAV2 uses the PCF8574A, while the I2C-OC805SV2 uses the PCF8574. These two chips have different I2C addresses.

Note: The power dissipation of the ULN2803A chip is an important factor for each application. You must calculate the power dissipation according to your specific usage.

Important Warning To prevent damage to the board, do not plug or unplug I2C cables while the power supply is on. Always turn off the power supply before connecting or disconnecting I2C cables.