ZHCSII0A July 2018 – November 2018 ADS1219
PRODUCTION DATA.
The unidirectional, high-side load current measurement is implemented using a shunt resistor, RShunt, and a current-sense amplifier, INA180, with a gain of 100. To meet the requirement of a maximum voltage drop across RShunt of 20 mV at the maximum current of 10 A, the shunt resistor must be RShunt ≤ 20 mV / 10 A = 2 mΩ. The output signal of the INA180 is fed single-endedly to input AIN2 of the ADS1219. Consequently, the voltage at AIN2 ranges from 0 V to (2 mΩ · 10 A · 100) = 2 V, which can be measured using the internal 2.048-V reference and gain = 1 of the ADC.
Equation 7 through Equation 9 describe the relationship between output codes of the ADS1219 and the current across the shunt resistor.