PCF8575CTS/1,112

I/o Expanders Overview

The PCF8575CTS/1,112 is a silicon CMOS remote 16-bit I/O expander for the I2C-bus. It provides general-purpose expansion via two bidirectional lines (SDA and SCL). The device features 16 quasi-bidirectional ports (P00–P07, P10–P17) with latched outputs capable of directly driving LEDs. Operating supply voltage ranges from 4.5 V to 5.5 V, with a maximum standby current of 10 μA. It supports FAST I2C-bus speeds up to 400 kbits/s. Addressing is configured by three hardware pins (A0, A1, A2), allowing up to eight devices on one bus. An open-drain interrupt output (INT) signals port state changes.

I/o Expanders Feature Summary

• Provides 16-bit remote I/O expansion through a standard two-line I2C interface.
• Features quasi-bidirectional ports that operate without explicit direction control signals.
• Includes an open-drain interrupt output to notify the microcontroller of input events.
• Supports multiple device addressing using three hardware address pins.

I/o Expanders Applications

• Remote digital input/output expansion for microcontrollers
• Direct LED driving applications
• I2C bus slave transmitter/receiver systems

I/o Expanders Procurement Notes

Verify the package type matches the SSOP24 specification (SOT340-1) with a body width of 5.3 mm. Confirm the operating voltage range requirements align with the specified 4.5 V to 5.5 V limit. Ensure the design accommodates the low standby current consumption of 10 μA maximum. Check compatibility with the target microcontroller's I2C timing parameters.

I/o Expanders Selection Notes

Select this component when a system requires expanding GPIO count via I2C without complex configuration registers. The quasi-bidirectional nature simplifies software logic but requires careful handling of high-level inputs on previously low-written pins to avoid excessive current flow. Verify that the host controller supports the required I2C clock frequency and acknowledge protocols.

I/o Expanders Part Context

This part belongs to the PCF8575C family of remote I/O expanders manufactured by Philips Semiconductors (now NXP). It utilizes an SSOP24 plastic shrink small outline package. The device functions as a slave on the I2C bus, translating serial data into parallel port states or vice versa.

I/o Expanders Replacement Considerations

Compatible substitutes include other 16-bit I2C I/O expanders such as the PCA9535 or PCA9555, provided they support similar voltage ranges and interrupt functionalities. Ensure pinout compatibility or verify necessary schematic modifications during replacement.

I/o Expanders FAQ

How does the quasi-bidirectional I/O function?

The ports act as inputs or outputs without a dedicated direction register. Writing a '1' sets the pin to a high-impedance input state, while writing a '0' actively drives it low. Reading returns the external pin state.

What triggers the interrupt output?

An interrupt is generated by any rising or falling edge on the port inputs. The INT signal remains active until the port data is read or written, resetting the interrupt condition.

Can multiple PCF8575CTS devices share the same bus?

Yes, up to eight devices can be connected to a single I2C bus by configuring the three hardware address pins (A0, A1, A2) to unique combinations.