SBAU411 February 2023 ADS127L21
#GUID-ADEF0F13-5A0E-431F-AAB8-F778196195A1 shows connections to external supplies for the amplifier, reference, and data converter. The default state of the EVM is that the power is provided by the PHI digital controller board via the USB port. The external power connections can be used in cases where the PHI does not provide the needed voltage. For example, the PHI does not provide negative voltages, so if a negative AVSS is needed an external power supply is required. To use the external power connections for AVDD and IOVDD, remove the 0-Ω resistor connections (R71, R74, and R81). Connector J12 can optionally be used to supply power to the onboard 5-V and –2.5-V regulators. In this case, the allowable voltage range for –VinExt is –15.5 V < –VinExt < –3.5 V and +VinExt is 6 V < +VinExt < 15.5 V.