SLWU067D November   2009  – March 2022 ADS4122 , ADS4125 , ADS4126 , ADS4128 , ADS4129 , ADS4142 , ADS4145 , ADS4146 , ADS4149 , ADS41B25 , ADS41B29 , ADS41B49 , ADS58B18 , ADS58B19

 

  1.   Trademarks
  2. 1Overview
    1. 1.1 Purpose
    2. 1.2 EVM Quick-Start Procedure
  3. 2Circuit Description
    1. 2.1 Schematic Diagram
    2. 2.2 Circuit Function
      1. 2.2.1 Power
        1. 2.2.1.1 Power Supply Option 1
        2. 2.2.1.2 Power Supply Option 2
        3. 2.2.1.3 Power Supply Option 3
      2. 2.2.2 Clock Input
        1. 2.2.2.1 Clock Option 1
        2. 2.2.2.2 Clock Option 2
        3. 2.2.2.3 Clock Option 3
      3. 2.2.3 Analog Inputs
        1. 2.2.3.1 Analog Input Option 1
        2. 2.2.3.2 Analog Input Option 2
      4. 2.2.4 Digital Outputs
  4. 3TI ADC SPI Control Interface
    1. 3.1 Installing the ADC SPI Interface
    2. 3.2 Setting Up the EVM for ADC SPI Control
    3. 3.3 Using the TI ADC SPI Interface Software
      1. 3.3.1 SPI Register Writes
  5. 4Quick Start Setup
  6. 5Evaluation
    1. 5.1 Register Programming
    2. 5.2 Quick-Test Results

2.2.1 Power

Power is supplied to the EVM through banana jacks; from this input power, three different ways are available of delivering power to the ADC and the other EVM functions . Figure 2-3 shows a simplified representation of the power options available for the ADS41xx/58B18EVM. The default option is to provide 3.3 V to the red banana jack J16, and from there the EVM generates 1.8 V for the analog and digital supplies to the ADC. The 1.8-V rails for the ADC can be generated from the 3.3-V input either through a low-noise dropout regulator (TPS79618), from a switching regulator (TPS62562) for maximum power efficiency or from an external 1.8-V power supply. The EVM also generates the proper voltages for optional features of the EVM such as the Clock Generation circuitry, the USB circuitry, and the CMOS output buffer.

GUID-D906DF61-0848-4158-A62E-B1F3588A7DAA-low.gifFigure 2-3 ADS41xx/58B18EVM Power Distribution

Some ADC devices that may be evaluated on the ADS41xx/58B18 platform require a 3.3-V supply for an internal front-end buffer. For this reason, an isolated 3.3V_BUF supply is on the power section of the schematic.

Power for the optional THS4509 operational amplifier is supplied by banana jacks J9 and J11. If the amplifier is being evaluated, 5 V is supplied to J9 and J11 is connected to ground. Otherwise, these inputs may be left unconnected.

The power supply for the default operation of the ADS41xx/58B18EVM has been simplified by requiring only a single 3.3 V. Table 2-1 displays the general jumper setting information; Table 2-2 displays the various power option settings. Prior to making any jumper settings, see the schematic located on the TI Web site in the relevant ADS41xx or ADS41Bxx product folder.

Table 2-1 EVM Power Supply Jumper Description
EVM Banana Jack/JumperDescriptionJumper setting
J16Input3.3-V power supply input
JP33.3 V for CDCE72010Shunt for CDCE72010 operation
JP131.8-VA input1-2 → 1.8 V from LDO/switching regular to 1.8 VA of ADC (default); 2-3 → option for external 1.8-V supply
JP141.8-VD input1-2 → 1.8 V from LDO/switching regular to 1.8 VD of ADC (default); 2-3 → option for external 1.8-V supply
JP173.3-V input selection for LDO/switching regulator1-2 → 3.3-V input for TPS62562 (default); 2-3 → 3.3-V input for TPS79618
JP191.8-V selection from LDO/switching regulator1-2 → 1.8-V output from TPS62562 (default); 2-3 → 1.8-V output from TPS79618
Table 2-2 EVM Power Supply Options
EVM OptionEvaluation GoalJumper Changes RequiredVoltage on J16Comments
1Evaluate ADC performance using a switching power supply (TP62562)JP13 → 1-2; JP14 → 1-2; JP17 → 1-2; JP19 → 1-2;3.3 VMaximum performance and efficiency.
2Evaluate ADC performance using a LDO-based (TPS79618) solution.JP13 → 1-2; JP14 → 1-2; JP17 → 2-3; JP19 → 2-3;3.3 VMaximum performance.
3Evaluate ADC performance using an isolated ADC AVDD and DVDD for current consumption measurementsJP13 → 1.8V on 2-3; JP14 → 1.8V on 2-3; JP17 → open3; JP19 → open;3.3 VIsolated power supply for current consumption measurements