Nano-power switched-capacitor bandpass filters for medical implantable pacemakers and defibrillators

This paper presents switched-capacitor bandpass filters used within the sense system of implantable medical devices such as cardiac pacemakers and defibrillators. This work examines the methods; including filter architecture, discrete-time transformation, and operational amplifier (opamp) topology; to reduce current consumption and to lower supply voltages for switched capacitor filters to reach nano-watt level of power consumption. The implemented fourth-order intra-cardiac signal bandpass filter is in a standard analog CMOS process and has power consumption of 210 nW using 1024 Hz system clock.