When selecting a microcontroller, it is advised that at least one 12-bit (minimum) ADC be available for conversion of the output from the MAX14920/MAX14921. ADC characteristics will typically scale with the cost of the microcontroller, so selecting a microcontroller within the budget is the most optimization needed here.
The resistor values are the most controllable parameter in this architecture. Consider an application with a maximum cell voltage of 4V and a 1.195V reference on the ADC. The 4V input must be divided down to 1.195V to match the full-scale voltage capabilities of the ADC. Once the conversion is completed, the output value must then be multiplied by the IN/OUT ratio to regain the original 4V scale. The division of the input, conversion, and subsequent multiplication of the output introduces three sources of error.
The first form of error introduced by the voltage-divider is the error caused by imperfect resistor values because calculated values are unavailable. For example, selecting R 1 = 1MΩ requires that R 2 = 2.347MΩ. Such precise values are not available, so the designer must settle for a close value that is available for purchase. In this case both 2.32MΩ and