Use of  right leg drive amplifier

Document created by analog-archivist Employee on Feb 23, 2016
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What is the right leg drive amplifier used for? Do I need to use it?


The Right Leg Drive (RLD) amplifier can reduce the common-mode voltage
interference that typically affects biopotential measurements. For enhanced
performance a three electrode solution is recommended (where the third
electrode is the output of the RLD amplifier).

A performance somewhere in between the two and three electrode solutions can be
achieved with a two electrode system where the RLD amplifier instead of driving
its own electrode, drives the input pull up resistors where VIN+ and VIN- are
connected to (see Figure 62 in the datasheet).

Heart Rate monitors (for peak detection) with short cables, such as a chest
strap may not need to use the RLD amplifier. Applications with long cables will
benefit the most.