This training covers the fundamental design techniques required to implement a successful capacitive sensing hardware design. This series will explore a number of design topics, including: Basic layout guidelines overlays, back lighting; Dealing with moisture; Self capacitance sensors; Mutual capacitance sensors; and Proximity sensors.
For anti-tampering, it is common to try to detect the presence of a strong magnet. In this section, we will cover the use of hall sensors for low-power detection of strong magnetic fields in three dimensions. Details on our magnetic tamper detection reference design, TIDA-00839, will be provided as well as some of the design considerations that were kept in mind when creating this reference design.
In this section, we will cover how to harden a meter against these magnetic tamper attacks by using shunts for current sensors. For poly-phase implementations, I will go over how to use isolated delta sigma modulators to add the necessary isolation to use shunt current sensors and create magnetically immune poly-phase energy measurement systems. The TIDA-00601 and TIDA-01094 reference designs, which show how to implement a poly-phase isolated shunt measurement system, will be discussed as well as the associated AMC1304 high-side power supplies used in these designs.
The TMP116 digital precision temperature sensor for the -55 to +125ºC range achieves higher accuracy than the Class AA PT sensor with a 1-point calibration. A small PCB including TI's TPD1E10B06 or TPD1E04U04 protection devices can be sealed into a RTD metal tube and meet the EN 61000-4-2 and -4-4 levels of ESD protection. The 64-bit internal EEPROM inside TMP116 stores user defined calibration data into the digital temperature sensor, simplifying integration with application MCUs, such as MSP430FR6047, FR6989 or CC13xx/26xx wireless MCU families.