ABSTRACT
This chapter provides switched-capacitor (SC) filter for extreme environment application and a second-order low-pass filter with novel tunable CMOS resistor. The SC filters present some advantages such as its programmability of the cutoff frequency by means of varying the clock frequency. The clock frequency of the SC filter is much higher than its cutoff frequency. With the development of aerospace exploration, design considerations for extreme environments have attracted attentions. Key to the success of developing a system in an extreme temperature range is to realize a robust and precise reference source. For an SC filter, the op-amp’s performance is sensitive to the accuracy and stability of the on-chip current reference. The clock phase control is an important issue in the switched capacitor filter design. Dual clock phases are used as the non-overlapped clock phases for this SC filter. Active tunable resistors are used in a lot of applications such as voltage controlled amplifiers, automatic gain control systems, and tunable filters.
