This paper describes the development of a very low-power preamplifier inten
ded for use in pasteless-electrode recording of the human electrocardiogram
, The expected input signal range is 100 mu V-10 mV from a lead-II electrod
e configuration. The amplifier provides a gain of 43 dB in a 3-dB bandwidth
of 0.05 Hz-2 kHz with a defined high input impedance of 75 M Omega. It use
s a driven common electrode to enhance rejection of common-mode interfering
signals, including low-frequencg motion artifact, achieving a common-mode
rejection ratio (CMRR) of better than 80 dB over its entire bandwidth, The
gain and phase characteristics meet the recommendations of the American Hea
rt Association, ensuring low distortion of the output ECG signal and making
it suitable for clinical monitoring. The amplifier has a power consumption
of 30 mu W operating from a 3.3-V battery and is intended for use in small
, lightweight, portable electrocardiographic equipment and heart-rate monit
oring instrumentation.