9.2.2 Detailed Design Procedure

In order to take one reading from each of the three input signals within 100 ms, the ADS1219 must use a data rate of 90 SPS or faster. When using a data rate setting of 90 SPS, every conversion takes approximately 11.3 ms according to Table 4. Consequently, all three signals can be measured within approximately 34 ms when also accounting for the time to read conversion results and to write new configuration register settings between conversions.

All three signal measurements use a single-ended measurement implementation. The voltage and current measurements use the GND connection within the MUX, whereas the thermistor measurement uses an external GND connection through AIN1 to showcase the two different options for implementing a single-ended measurement.

RC filters are provided on all three analog inputs of the device, which act as antialiasing filters and to limit the current into the analog inputs in case of overvoltage events. The filter component values are chosen according to the guidelines in the Analog Input Filtering section as R_F = 1 kΩ and C_F = 100 nF to create a filter corner frequency of f_C = 1 / (2π · R_F · C_F) = 1.6 kHz.