A MOS switched-capacitor ladder filter in SIMOX technology for high temperature applications up to 300/spl deg/C

This paper describes techniques and methods used to realize a seventh order switched-capacitor low pass filter in SIMOX technology. The filter has Bessel characteristic and a 3 dB-bandwidth of 20 Hz at a clock frequency of 100 kHz. Special design of transistors and transmission gates results in drastically reduced leakage currents at high temperatures. The power supply voltage of the switched-capacitor filter is 10 V. The temperature range is extended up to 300/spl deg/C. Experimental results of the transistors, the transmission gates, the operational amplifier, and the complete filter are presented.