ADT7421ARMZ-RL7

Overview

The ADT7421ARMZ-RL7 is a dual-channel digital thermometer and under/overtemperature alarm manufactured by onsemi. It features Beta Cancellation Technology for accurate measurement of small geometry CPU temperatures, with local accuracy of ±2.75°C and remote accuracy ranging from ±1.75°C to ±3.25°C. The device operates on a 3.0 V to 3.6 V supply, drawing up to 4.0 mA at maximum conversion rates. It provides 1°C resolution locally and 0.25°C remotely via a 2-Wire SMBus interface. The sensor supports switchable temperature ranges of 0°C to +125°C or -40°C to +125°C in an 8-lead MSOP package.

Feature Summary

• Beta Cancellation Technology automatically compensates for thermal transistor variations in sub-45 nm processes.
• Series Resistance Cancellation neutralizes parasitic resistance effects on the remote channel.
• Dual output configuration allows ALERT interrupt signaling or THERM fan control functionality.

Applications

• Desktop and notebook computer thermal management
• Industrial controller temperature monitoring
• Smart battery pack protection systems

Procurement Notes

Verify component authenticity through authorized distribution channels. Confirm RoHS compliance status and lead-free packaging specifications prior to integration. Ensure storage conditions adhere to moisture sensitivity level requirements to prevent package damage during soldering.

Selection Notes

Select this model when precise monitoring of embedded thermal transistors in modern processors is required. The integrated beta cancellation eliminates the need for external calibration. Verify that the system voltage remains within the 3.0 V to 3.6 V operational window.

Part Context

This component belongs to the ADT7421 family of precision temperature sensors. It maintains pin and register compatibility with legacy devices such as the ADM1032 and ADT7461, facilitating direct upgrades in existing designs without schematic modifications.

Replacement Considerations

Direct substitutes include the ADT7421ARMZ and ADT7421ARMZ-REEL. These variants share identical electrical characteristics and pinouts but differ only in reel packaging quantities rather than functional performance.

FAQ

How does the ADT7421 handle series resistance on the remote sensor?

The device automatically cancels up to 50 Ohms of typical series resistance found on the D+ and D- inputs, removing the need for manual offset calibration.

What is the default SMBus address for this sensor?

The default SMBus address is 0x4C. An alternative address of 0x4D is available for the ADT7421-2 variant to support multiple devices on the same bus.

Can the ALERT output be used as a second temperature threshold trigger?

Yes, Pin 6 can be reconfigured via the Configuration Register to function as a second THERM output (THERM2) instead of an alert interrupt.