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Description:
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This thesis investigates the various techniques to achieve large time constants and the ultimate limitations therein . A novel circuit technique for the realization of large time constants for high pass corners in switched -capacitor filters is also proposed and compared with existing techniques . The switched -capacitor technique is insensitive to parasitic capacitances and is area efficient and it requires only two clock phases . The circuit is used to build a typical switched -capacitor front end with a gain of 10 . The low pass corner is fixed at 200 Hz . The high pass corner is varied from 0 .159Hz to 4 Hz and various performance parameters , such as power consumption , silicon area etc . , are compared with conventional techniques and the advantages and disadvantages of each technique are demonstrated . The front -ends are fully differential and are chopper stabilized to protect against DC offsets and 1 /f noise . The front -end is implemented in AMI0 .6um technology with a supply voltage of 1 .6V and all transistors operate in weak inversion with currents in the range of tens of nano -amperes . |