ADS131M04: Schematic review

Hi Reha,

Please see my feedback below.

• Pin 12 (/CS) should be tied to GND not DVDD if the customer does not want to control it from their microcontroller.
• The customer copied the circuit of power supply from ADS131M04EVM, the 0.1ohm resistors used for AVDD and DVDD on the EVM are designed to measure current if any customer wants to know how much current the ADC consumes, so R12 and R13 in this customer's schematic can be removed if this customer does not have such requirement.
• The burden resistors on the ADS131M04EVM are designed and selected based on the current range used and the turns ratio specification of the CT (current transformer) when customers want to use input channels for current measurement. Two identical burden resistors are used in series with the common point being connected to GND instead of using one burden resistor for best THD performance. This split-burden resistor configuration ensures that the waveforms fed to the positive and negative terminals of the ADC are 180 degrees out-of-phase with each other, which provides the best THD results with this ADC. If this customer does not use these channels for current measurement, these resistors (e.g. R3 and R4 on AIN0) are not needed.
•  Analog input (AIN3) can be left floating but connecting it to GND would be a safe solution because a floating input could potentially float to a voltage out of range of the ADC device which could present problems.
• A solid ground plane is recommended for best performance if ground separation (AGND and GND) is not necessary.
• The input protection is good as the customer copied the circuit from our app note.

BR,

Dale