In continuation to the above usage, ISOMOS can also be used to set or un-set the precision burden resistor that can range between 50Ω to 250Ω as shown in Figure 2-4. As the front end typically accepts voltage input, 4-20mA current input needs to be converted into voltage for post processing. For this reason, a precision burden resistor is used to convert the 4-20mA current signal to a proportional voltage that is fed to the ADC input.

When ISOMOS is closed by setting it's corresponding control signal to High, the particular channel is in current input mode, otherwise in voltage input mode. In current input mode, ISOM8610 comes in series with the precision burden resistor and introduces variable resistance over temperature. Therefore, care must be taken to eliminate the variation by assigning an extra ADC channel to sense voltage across the burden resistor, which eliminates variable drop across the switch. If the number of ADC channels are limited, one can also eliminate the on-state resistance of ISOM8610 by compensating the voltage reading with R_ONDrift.

In voltage input mode, ISOM8610 is turned off by setting its control input to Low. ISOM8610 independently blocks the incoming analog voltage with ease and does not distort the incoming voltage signal due to minimal leakage of <1μA across temperature.