In emerging technologies such as AR/VR headsets, achieving fast thermal response times and high accuracy can help optimize performance, safety, and user experience. Fast thermal response times minimize the delay between actual and measured temperatures, which is essential in environments where immediate reaction to temperature changes is necessary to prevent system failures and enhance reliability.
This application note examines the thermal response characteristics of the TMP116 (0.20°C accuracy), TMP117 (0.10°C accuracy), and TMP119 (0.08°C accuracy) temperature sensors. The application note highlights the impact of package selection and PCB design on thermal performance. Sensors with lower thermal mass, like the TMP117, in the DSBGA package, offer a faster thermal response times compared to those in WSON/QFN packages, due to the reduction the IC thermal mass. Achieving real-time precise surface temperature measurements in various applications, it is important to have minimal thermal resistance between the measured object surface and the sensor package. High thermal resistance can lead to sensor temperature shift from the measured object, as well as a delayed thermal response time.
This application note provides information about thermal resistance measurements made for different kinds of sensor packages mounted on varying thicknesses of rigid PCB, as well as flexible PCB. Flexible PCB, with reduced thermal mass, demonstrate significant advantages in settling time, achieving quicker and more accurate temperature readings.
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High-accuracy temperature sensing is critical in many applications. Achieving this requires minimal thermal resistance between the measured object surface and the sensor package. High thermal resistance can cause a sensor's temperature reading to shift away from the actual object temperature and delay thermal response time. This application note details the thermal resistance measurements conducted on different sensor packages, such as the TMP116, TMP117, and TMP119, mounted on varying thicknesses of rigid PCB and flexible PCB.
The primary objective of these measurements was to understand how package selection and PCB design impact thermal performance. By comparing sensors with different thermal masses and configurations, we aimed to identify the setups that provide the quickest and most accurate thermal response. Sensors with lower thermal mass, like the TMP117 and TMP119 in a WCSP DSBGA package, showed significantly faster response times than those in WSON/QFN packages, highlighting the importance of reducing the IC thermal mass.
Additionally, flexible PCB were examined due to their potential for reducing overall thermal mass and enhancing thermal performance. Our experiments demonstrated that flexible PCB can achieve quicker and more accurate temperature readings than rigid PCB. This finding underscores the benefits of flexible PCB in applications where rapid thermal response is essential.
This document provides detailed results from these thermal resistance measurements and offers practical design tips for optimizing the thermal response of temperature sensors in various applications. By leveraging the insights from this study, designers and layout engineers can make informed decisions about sensor packaging and PCB design to achieve designed for thermal performance.