AN 769: Intel FPGA Remote Temperature Sensing Diode Implementation Guide

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ID 683139
Date 4/06/2022
Public
Document Table of Contents
Document Table of Contents x
1. Introduction 2. Implementation Overview 3. Implementation Consideration 4. Evaluation Results 5. Conclusion 6. Document Revision History for AN 769: Intel FPGA Remote Temperature Sensing Diode Implementation Guide
3. Implementation Consideration x
3.1. Ideality Factor (η-Factor) Mismatch 3.2. Series Resistance Error 3.3. Temperature Diode Beta Variation 3.4. Differential Input Capacitor 3.5. Offset Compensation
4. Evaluation Results x
4.1. Evaluation with Maxim Integrated* 's MAX31730 Temperature Sensing Chip Evaluation Board 4.2. Evaluation with Texas Instruments* 's TMP468 Temperature Sensing Chip Evaluation Board
1. Introduction
2. Implementation Overview
3. Implementation Consideration
4. Evaluation Results
5. Conclusion
6. Document Revision History for AN 769: Intel FPGA Remote Temperature Sensing Diode Implementation Guide

3.4. Differential Input Capacitor

The capacitor (CF) on P and N pins acts like a low-pass filter that helps to filter the high frequency noise and improve the electromagnetic interference (EMI).

You must be careful during capacitor selection because the large capacitance can affect the rise time of the switched current source and introduce a huge measurement error. Typically, the temperature sensing chip manufacturer provides the recommended capacitance value in their data sheet. Refer to the capacitor manufacturer's design guidelines or recommendation before you decide the capacitance value.

Figure 5. Differential Input Capacitance


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