PCA9535CD,112

I/o Expanders Overview

The PCA9535CD,112 is a 24-pin CMOS I/O expander providing 16 bits of General Purpose parallel Input/Output expansion for I2C-bus and SMBus applications. It operates within a supply voltage range of 2.3 V to 5.5 V with 5 V tolerant I/Os. The device features an active LOW open-drain interrupt output, polarity inversion registers, and noise filters on SCL/SDA inputs. It supports clock frequencies from 0 Hz to 400 kHz and includes ESD protection exceeding 2000 V HBM. The component is housed in an SO24 plastic small outline package.

I/o Expanders Feature Summary

• Provides 16 configurable GPIO pins with individual input/output direction selection via configuration registers.
• Features an active LOW open-drain interrupt output that signals state changes without continuous bus polling.
• Includes polarity inversion registers to allow flexible logic level interpretation for input data.

I/o Expanders Applications

• ACPI power switch control
• Sensor interface expansion
• Push button scanning
• LED driver control

I/o Expanders Procurement Notes

Verify the specific ordering suffix '112' corresponds to the tube packing method as documented in the NXP datasheet. Confirm the manufacturer designation matches NXP Semiconductors rather than other vendors offering compatible parts. Ensure the package type is identified as SO24 (SOT137-1) during receipt inspection.

I/o Expanders Selection Notes

Select this variant when an SO24 surface-mount package is required for the PCB layout. Choose the PCA9535CD over the PCA9535CPW if the board space accommodates the wider body width of the SOIC package. Verify that the application does not require internal pull-up resistors, as this version lacks them unlike the PCA9555.

I/o Expanders Part Context

This component belongs to the PCA9535 family of 16-bit I2C/SMBus I/O expanders. It is functionally identical to the PCA9555 but excludes internal I/O pull-up resistors to reduce power consumption when outputs are held low. It maintains pin-to-pin and address compatibility with the PCF8575 series, though software modifications are necessary due to architectural enhancements.

I/o Expanders Replacement Considerations

The PCA9535D,112 serves as a direct replacement within the same package family. The TCA9535 is also pin-compatible and register-compatible. Note that while physically interchangeable, software changes are required when migrating between these variants due to functional differences.