A compact solder joint resistance sensor with 200mΩ range and 100μΩ resolution

For safety-critical automotive and robotics applications physical health sensing and failure-prediction are required to meet stringent reliability requirements. To detect and predict a failure[1] in the PCB interconnect interface of a chip requires accurate on-chip measurement of the solder-joint resistance.

The challenges associated with the on-chip solder-joint measurement are besides the small resistance range of 200mΩ, required resolution of 100μΩ the accuracy over time and limited force current. Previous work related to a current sensor design[2] shows that it should be feasible to achieve the required resistance resolution when a 100mA force current is applied through the resistance and then measuring the voltage. For the resistance measurement in this application the absolute accuracy over time is also important which can be obtained using a ratiometric measurement using an on-chip reference resistor. In this project you will look into achieving the required resistance measurement resolution while minimizing the force current,  ensuring accuracy over time and with a small die size.

The project includes the design and tape-out of a prototype chip in 160nm technology.

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