PCA9535PW,112

I/o Expanders Overview

The PCA9535PW,112 is a 24-pin CMOS device providing 16 bits of General Purpose parallel Input/Output expansion for I2C-bus/SMBus applications. It operates within an operating power supply voltage range of 2.3 V to 5.5 V and supports clock frequencies from 0 Hz to 400 kHz. The device features 5 V tolerant I/Os, low standby current, and an active LOW interrupt output. It includes polarity inversion registers and noise filters on SCL/SDA inputs. The package is TSSOP24 with dimensions of 7.9 mm length, 4.4 mm width, and 1.1 mm height.

I/o Expanders Feature Summary

• Provides 16 configurable general-purpose I/O pins accessible via standard I2C or SMBus interfaces.
• Features an open-drain interrupt output that activates when input states change relative to the Input Port register.
• Includes polarity inversion registers to allow active HIGH or active LOW operation without software changes.

I/o Expanders Applications

• ACPI power switches
• Sensor interface expansion
• Push button status reading
• LED control circuits

I/o Expanders Procurement Notes

Verify the specific ordering suffix '112' corresponds to the bulk pack configuration as defined in NXP documentation. Confirm the manufacturer designation aligns with NXP Semiconductors specifications rather than third-party distributors. Ensure the component matches the TSSOP24 package variant listed in the official datasheet.

I/o Expanders Selection Notes

Select this component when 16-bit GPIO expansion is required over I2C/SMBus with low power consumption. It serves as a low-power alternative to the PCA9555 by removing internal I/O pull-up resistors. Verify compatibility with system voltage levels between 2.3 V and 5.5 V and ensure sufficient I2C bus address space for up to eight devices.

I/o Expanders Part Context

The PCA9535 series enhances the NXP family of I2C-bus I/O expanders with higher drive capability and smaller packaging. It is pin-to-pin and address compatible with the PCF8575 but requires software adjustments due to architectural enhancements. The device shares the same fixed I2C address structure as the PCA9555, allowing mixed combinations on the same bus.

I/o Expanders Replacement Considerations

PCA9535CPW,112: Identical function but with open-drain outputs only.

I/o Expanders FAQ

How does the PCA9535 differ from the PCA9555?

The PCA9535 removes the internal I/O pull-up resistors found in the PCA9555, which significantly reduces power consumption when the I/Os are held LOW.

What is the default state of the I/O ports at reset?

At power-on reset, all 16 I/O pins default to input mode with high-impedance drivers.

Can multiple PCA9535 devices share the same I2C bus?

Yes, three hardware address pins (A0, A1, A2) allow up to eight devices to share the same I2C bus/SMBus.