A 14-bit 100-kHz continuous-time delta-sigma analog-to-digital converter for Hall effect based current sensor application

Systems on chip can integrate a number of different functions in a single die and replace a PCB with many discrete components with a single integrated circuit. Therefore their popularity increased over years. Sensor systems are good examples of system-on-chip designs. This work is also a part of a sensor system on a chip. The sensor system consists of sensor cores, preamplifiers, analog-to-digital converter, digital calibration and digital-to-analog converter. System needs an analog-to-digital converter because calibration of the sensor is in digital domain. Delta sigma ADC is preferred due to the sensor system requirements of high-resolution and low speed. Integrated circuit design steps are modelling, schematic level design, physical design and lab measurements after production. In this work, first, Simulink and Verilog-A model of full ADC system is prepared and requirements of sensor system are satisfied. SNQR of the ADC is about 100 dB using ideal models. Next, ideal blocks are replaced with their schematic level realizations using transistors, resistors and capacitors that are provided by the foundry. TSMC 0.18um process is used in this work. In this step, non-idealities affect the system performance and SQNR of the ADC is reduces to 87 dB. Following schematic level design, physical design step starts. During physical design, Placement of each component on the chip and their interconnections are realized. There are some verification steps that ensure the physical design is ready for production (DRC, LVS, ERC, etc.). After these verifications are completed, post layout simulations are executed. Post-layout simulation adds parasitics effects to the simulation to have more realistic results. SQNR of the ADC including post-layout parasitics is around 77 dB, which meet our specification. After manufacturing the chip is charaterized in our test labs Since the chip is not only an ADC chip, but a sensor system on chip and the ADC is a sub-block of this sensor system some problems arose during measurements of the ADC. However, the ADC works mostly as expected in the system chip. As a conclusion, a delta sigma ADC for a sensor system on chip application is designed and realized in this work with using a common integrated circuit design flow. After manufacturing the chip is characterized and the ADC is found to be functional.