PCA9555DB,112

I/o Expanders Overview

The PCA9555DB,112 is a 24-pin CMOS device providing 16-bit General Purpose parallel Input/Output (GPIO) expansion for I2C-bus/SMBus applications. It operates within a supply voltage range of 2.3 V to 5.5 V and supports clock frequencies from 0 Hz to 400 kHz. The device features five packages; this specific part number utilizes the SSOP24 plastic shrink small outline package with 24 leads and a body width of 5.3 mm. It includes an active LOW interrupt output, polarity inversion registers, and internal power-on reset. ESD protection exceeds 2000 V HBM per JESD22-A114, 200 V MM per JESD22-A115, and 1000 V CDM per JESD22-C101.

I/o Expanders Feature Summary

• Provides 16 bits of general-purpose parallel input/output expansion via I2C-bus or SMBus interface
• Features individual I/O configuration allowing each pin to be set as input or output
• Includes an open-drain interrupt output activated when any input state differs from its corresponding register
• Supports up to eight devices on the same bus using three hardware address pins

I/o Expanders Applications

• ACPI power switches
• Sensors
• Push buttons
• LEDs
• Fans

I/o Expanders Procurement Notes

Verify the ordering suffix '112' corresponds to the tube packing method and standard marking for the SSOP24 package. Confirm the minimum order quantity aligns with the specified bulk pack requirements. Ensure the ambient temperature range meets the application needs, as the device is rated for -40 °C to +85 °C. Cross-reference the type number with the manufacturer's current product data sheet to confirm availability and revision status.

I/o Expanders Selection Notes

Select this component when 16 additional GPIOs are required for I2C-based systems. The SSOP24 package offers a compact form factor suitable for space-constrained designs. Consider the 5 V tolerant I/Os if interfacing with mixed voltage logic levels. Verify that the system master can handle the required register configurations and interrupt handling logic as detailed in Application Note AN469.

I/o Expanders Part Context

The PCA9555 series enhances the NXP Semiconductors family of I2C-bus I/O expanders by offering higher drive capability, lower supply current, and smaller packaging compared to predecessors like the PCF8575. While pin-to-pin and I2C-bus address compatible with the PCF8575, software changes are necessary due to these enhancements. The fixed I2C-bus address is shared with the PCA9554, allowing flexible combinations on the same bus.

I/o Expanders Replacement Considerations

PCF8575: Pin-compatible but requires software updates due to functional differences.

I/o Expanders FAQ

How many devices can share the same I2C bus?

Up to eight devices can share the same I2C-bus/SMBus using the three hardware address pins A0, A1, and A2.

What happens to the I/O pins at power-on reset?

At reset, all 16 I/O pins default to inputs with high-impedance output drivers and a weak pull-up to VDD.

Can the PCA9555 be used with 5V logic?

Yes, the device supports a supply voltage range of 2.3 V to 5.5 V and features 5 V tolerant I/Os.