A fully-integrated two-channel A/D interface for the acquisition of cardiac signals in implantable pacemakers

This work presents an input stage for a cardiac pacemaker fully integrated in a 0.35/spl mu/m CMOS technology. The system can acquire and digitize to 8 bits both atrial and ventricular electrical activity. Log-domain circuits are exploited to amplify and filter the input signal, while /spl Sigma//spl Delta/ modulation is exploited to convert it. The design is power optimized, indeed the power consumption is limited to 4.8/spl mu/W with a power supply down to 1.8V. The total area is 2.2mm/sup 2/ and experimental data prove correct filtering and a total DR of at least 47dB.