NCT7717U TR

Overview

The NCT7717U TR is a local thermal sensor IC manufactured by Nuvoton Technology Corporation. It features an integrated 8-bit ADC providing 1°C resolution temperature measurement with typical accuracy of ±2°C between 20°C and 40°C, and maximum accuracy of ±3°C across the -40°C to +125°C range. The device operates on a 3.3V supply with a typical operating current of 700 µA. It utilizes an SMBus interface for data access and includes an ALERT# pin for hardware power-on setting or interrupt control. The component is available in SOT-23-5 packages.

Feature Summary

• Supports SMBus interface with byte write and read protocols for register access
• Provides active-low open-drain ALERT# output for system protection or shutdown
• Enables hardware power-on alert point configuration via pull-up resistors
• Offers configurable conversion rates and fault queue functions

Applications

• PC motherboard monitoring
• Notebook thermal management
• Embedded environment temperature sensing

Procurement Notes

Verify the specific package variant (SOT-23-5 or TSOT-23-5) required for the design, as indicated by the suffix U or -T. Confirm that the application voltage aligns with the specified 3.3V ±5% operating range. Ensure the selected pull-up resistor value matches the desired hardware power-on alert threshold if utilizing that feature. Check availability status as distribution may vary by region.

Selection Notes

Select this component when a low-power, high-accuracy local temperature sensor is needed for systems requiring SMBus connectivity. The device is suitable for applications where hardware-based thermal shutdown is necessary without remote sensors. Consider the 8-bit resolution and ±2°C typical accuracy for standard commercial temperature monitoring tasks within the specified operating temperature range.

Part Context

The NCT7717U belongs to Nuvoton's thermal sensor IC family designed for embedded and computing environments. It provides on-die temperature sensing capabilities specifically optimized for PC and notebook architectures. The series supports I2C-compatible communication protocols, facilitating integration into existing system management buses for efficient thermal data acquisition.

Replacement Considerations

NCT7717U-T serves as the alternative package version of the NCT7717U, offering identical electrical specifications in a TSOT-23-5 form factor instead of SOT-23-5.

FAQ

How is the default alert temperature determined upon power-up?

The default alert temperature can be set via hardware strapping using different pull-up resistor values connected to the ALERT# pin, such as 2kΩ for 75°C or 7.5kΩ for 90°C.

What are the available ALERT# output modes?

The NCT7717U supports three ALERT# output modes: comparator mode, interrupt mode, and SMBus alert mode, which can be configured via the Configuration Register.

What is the temperature measurement data format?

The local temperature data is provided in an 8-bit two's complement digital format with a 1°C resolution.