10.2.2 Detailed Design Procedure

The analog inputs, AIN0 and AIN3, connect directly to the supply voltage rails that are monitored through RC filter resistors. Small filter resistor values of 100 Ω are chosen to reduce voltage drops, and therefore offset errors, caused by the input currents of the TLA2024 to a minimum. Filter capacitors of 0.47 µF are chosen to set the filter cutoff frequencies at 3.39 kHz. In order to get one reading from each of the two supplies within 2 ms, a data rate of 2400 SPS is selected. The device is set up for single-ended measurements using MUX[2:0] settings 100 and 101. A FSR = ±4.096 V is selected to measure the 3.3-V rail. The same FSR can also be used to measure the 1.8-V rail or the FSR can be set to FSR = ±2.048 V.