NCA9555

Overview

The NCA9555 is a 16-bit I2C-bus I/O port manufactured by NOVOSENSE, designed for general-purpose parallel input/output expansion in I2C applications. It operates within a supply voltage range of 2.3V to 5.5V and supports clock frequencies up to 400 kHz. The device features an open-drain interrupt output and utilizes a 24-TSSOP package with dimensions of 0.173 inches (4.40mm) width. It functions across a temperature range of -40°C to 85°C and provides 10mA current drive capability per output pin.

Feature Summary

• Provides 16-bit GPIO expansion via I2C and SMBus interfaces
• Supports hardware address selection for multi-device bus sharing
• Includes polarity inversion registers for flexible logic configuration
• Features internal power-on reset and noise filtering on SCL/SDA inputs

Applications

• ACPI power switch control systems
• Sensor interface expansion
• Button and LED indicator arrays
• Fan control circuits

Procurement Notes

Verify the specific ordering suffix against the manufacturer's official datasheet to ensure correct packaging options such as tape and reel or cut tape. Confirm that the selected variant meets the required moisture sensitivity level and RoHS compliance standards for your assembly process. Cross-reference the component status to ensure availability before finalizing procurement plans.

Selection Notes

Select this component when system design requires expanding microcontroller I/O lines using standard I2C communication protocols. Ensure the host controller supports the 400 kHz clock speed and can handle the open-drain interrupt signaling. Verify that the operating voltage range aligns with the target application's power supply constraints and that the thermal performance fits within the specified industrial temperature limits.

Part Context

The NCA9555 belongs to the family of CMOS I/O expanders produced by NOVOSENSE. It serves as a bridge between serial I2C buses and parallel digital ports, enabling efficient pin management in embedded systems. The device integrates essential protection features like ESD tolerance and latch-up immunity to ensure reliability in noisy industrial environments.

Replacement Considerations

Consult official substitution guides from NOVOSENSE for verified compatible alternatives. Do not assume functional equivalence with other manufacturers' 16-bit I/O expanders without verifying register compatibility and electrical specifications.

FAQ

How many devices can share the same I2C bus?

Up to eight NCA9555 devices can be connected to a single I2C bus by utilizing the three hardware address pins (A0, A1, A2) to set unique addresses.

What is the function of the polarity inversion register?

The polarity inversion register allows users to reverse the reading polarity of the input ports, providing flexibility in interfacing with active-low or active-high sensors without software modification.

Does the device support SMBus communication?

Yes, the NCA9555 is compatible with both I2C and SMBus protocols, supporting clock frequencies up to 400 kHz.