The 800-V battery-pack voltage is divided down to the voltage range of the ADS131M04-Q1 using a high-voltage resistor divider (R_H1, R_H2, R_H3, and R_L). Gain = 1 is used for channel 0 in this case to allow differential voltage measurements of V_IN0 = V_AIN0P – V_AIN0N = ±1.2 V. The battery-pack voltage measurement is a unipolar, single-ended measurement. Thus, only the voltage range from 0 V to 1.2 V of the ADS131M04-Q1 is used. Equation 11 calculates the resistor divider ratio.

The leakage current drawn by the resistor divider must be less than 100 μA in this example to avoid unnecessarily draining the battery. The resistance of the divider must therefore be larger than R_TOTAL ≥
V_{BAT_MAX} / I_LEAKAGE = 800 V / 100 μA = 8 MΩ. The resistor values are chosen as R_H1 = R_H2 = R_H3 = 2.8 MΩ and R_L = 12.4 kΩ. Thus, the maximum voltage across R_L is 1.18 V at V_{BAT_MAX} = 800 V, leaving some headroom to the maximum input voltage of 1.2 V of the ADS131M04-Q1.

The maximum resistance of a single resistor that can be used in an automotive circuit design is often limited to a certain value. Also, the maximum voltage a single resistor can withstand is limited. These reasons are why the high-side resistor of the divider is split into multiple resistors (R_H1, R_H2, and R_H3). Another reason is that in case a single resistor has a short-circuit fault, the remaining resistors still limit the current into the ADS131M04-Q1 analog input pin (AIN0P) to safe levels.