NCT7491RQR2G

Thermal Management Overview

The NCT7491RQR2G is a two-wire serially programmable hardware monitor manufactured by onsemi. It monitors two remote temperature zones and its own ambient temperature, featuring a PECI 3.0 single-wire interface for CPU temperature monitoring. The device implements an SMBus compatible master to read thermal sensors automatically. It controls three fans via PWM and monitors four fan speeds. Four analog inputs measure 12 V, 5 V, 2.5 V, and VCCP channels, while supply and PECI VTT voltages are also monitored. Values are compared against programmable limits to generate interrupts or therm outputs. It operates within a 3.0 V to 3.6 V supply range and supports -40°C to 125°C temperatures in a 24-lead QSOP package.

Thermal Management Feature Summary

• Integrates PECI 3.0 master interface for direct CPU temperature monitoring alongside SMBus compatible master functionality for automatic sensor reading.
• Provides automated thermal management through three PWM fan control outputs and four tachometer monitoring inputs with automatic speed control capabilities.
• Includes comprehensive voltage monitoring for system rails including 12 V, 5 V, 2.5 V, VCCP, VDD supply, and PECI VTT via dedicated analog inputs.
• Features series resistance cancellation on remote sensors to improve accuracy and generates alerts or therm outputs when monitored parameters exceed programmed limits.

Thermal Management Applications

• Server and workstation motherboard thermal management
• Data center hardware monitoring systems
• Industrial equipment cooling control

Thermal Management Procurement Notes

Verify the specific suffix RQR2G corresponds to the 24-lead QSOP package variant during procurement. Confirm that the operating temperature range meets the -40°C to 125°C requirement for your application environment. Ensure the 3.0 V to 3.6 V supply voltage aligns with your system design. Check for RoHS compliance status if required by your manufacturing standards. Validate the SMBus address configuration pins to prevent bus conflicts in multi-device setups.

Thermal Management Selection Notes

Select this component when PECI 3.0 integration is required for CPU monitoring alongside standard SMBus sensor access. Choose this part if the application demands simultaneous control of multiple fans and monitoring of various voltage rails. Consider this device for designs requiring series resistance cancellation for accurate remote sensing. Verify that the 24-lead QSOP package fits the available PCB space constraints.

Thermal Management Part Context

The NCT7491 belongs to onsemi's thermal monitoring family, designed for complex electronic systems requiring detailed environmental oversight. This specific model integrates both PECI and SMBus masters, distinguishing it from simpler monitors. It serves as a central hub for thermal and voltage data in high-performance computing environments.

Thermal Management FAQ

Does the NCT7491RQR2G support PECI 3.0?

Yes, the NCT7491RQR2G includes a PECI 3.0 single-wire interface specifically designed to monitor CPU temperatures.

How many fans can be controlled by this device?

The device can automatically control the speed of three fans using PWM control and monitor the speed of four additional fans.