||MOSFET-C filters is popular in analog filters, the major reason is the simplicity. They are easily implemented with opamps and have similar architectures to active RC filters , this saves much of the design time.|
The frequency response of analog continuous time filters is determined by resistors, capacitors, inductors or transconductors. However, the process variation, temperature drift and aging, make the integrated RC time constants vary about 30 percent ~.
We proposed a switched-capacitor tuning circuit , which can be used in MOSFET-C Filter and the novel tuning circuit doesn’t need off chip capacitor. The novel circuit has following advantages (1). Small chip size. (2). Simplicity (3). Low reference clock frequency.