The AD420 ground pin, designated GND, is the “high quality”ground reference point for the device. Any external loads on theREF OUT and VOUT pins of the AD420 should be returned tothis reference point. Analog and digital ground currents shouldnot share a common path. Each signal should have an appropriateanalog or digital signal return routed close to it. Using thisapproach, signal loops enclose a small area, minimizing theinductive coupling of noise. Wide PC tracks, large gauge wire,and ground planes are highly recommended to provide lowimpedance signal paths.