SLAU150A December   2004  – October 2021 ADS7881 , ADS7891

 

  1.   Trademarks
  2. 1Introduction
    1. 1.1 Features
    2. 1.2 Analog Interface
      1. 1.2.1 Signal Conditioning
      2. 1.2.2 Reference
    3. 1.3 Digital Interface
    4. 1.4 Power Supplies
  3. 2Using the EVM
  4. 3ADS78x1EVM Bill of Materials
  5. 4ADS78x1EVM Layout
  6. 5ADS78x1EVM Schematics
  7. 6Revision History

Power Supplies

The EVM accepts four power supplies.

  • A dual ±Vs DC supply for the dual-supply op amps. A ±12-V DC supply is recommended.
  • A single +5.0-V DC supply for the analog section of the board (ADC + reference).
  • A single +5.0-V or +3.3-V DC supply for the digital section of the board (ADC + address decoder + buffers).

There are two ways to provide these voltages.

  1. Wire in voltages, as listed in Table 1-8, at test points on the EVM.
Table 1-8 Power-Supply Test Points
Test Point Signal Description
TP11 +BVDD Apply a +3.3-V DC or +5.0-V DC voltage. See the respective ADC data sheet for the full range.
TP10 +AVCC Apply a +5.0-V DC voltage.
TP12 +VA Apply a +12.0-V DC voltage. Positive supply for the amplifier.
TP14 –VA Apply a –12.0-V DC voltage. Negative supply for the amplifier.
  1. Use the power connector J1 and derive the voltages elsewhere. Table 1-9 lists the pin out connections for J1. Set jumper W5 to short between pins 1-2 or pins 2-3 to short +3.3VD or +5VD, respectively, to be the buffer digital supply (+BVDD).
Table 1-9 Power Connector, J1, Pin Out
Signal Power Connector - J1 Signal
+VA (+12VA) 1 2 –VA (–12VA)
+AVCC (+5VA) 3 4 N/C
N/C 5 6 AGND
N/C 7 8 N/C
+3.3VD 9 10 +5VD