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

2.2.3 Analog Inputs

The EVM can be configured to use either a transformer-coupled input or a THS4509 amplifier input, both from a single-ended source. The SMA connector J6 provides the single-ended analog input to the transformer-coupled input of the ADC. The SMA connector J8 is not installed by default, but can be used to bring a differential input clock to the transformer-coupled input or to bring a single-ended input to the THS4509 input circuit. To set the transformer up for one of these options, the EVM must be configured as per the options listed in Table 2-6. Prior to making any jumper changes, see the schematic located on the TI Web site in the relevant ADS41xx or ADS41Bxx product folder.

Table 2-5 Analog Input Jumper Description
EVM Jumper options Description Jumper Setting
J6 Analog input single-ended.
J8 Analog input, can be used with J6 for differential input Not populated
J9 Power supply + Apply 5 V
J11 Power Supply - Ground
R98/106 AMP out+ R106 → Amp out+ is selected as the source of input to ADC; R98 → Use Analog input from J6 as signal source to ADC
R97/99 AMP out- R99 → Amp out+ is selected as the source of input to ADC; R97 → Use Analog input from J6 as signal source to ADC
R82/96 -Input select R82 → Differential signal input to transformer T1 (remove R84); R96 → negative input to amplifier
R94/95 +Input select R94 → single-ended input to transformer T1; R95 → positive input to amplifier
JP7 Power down for amplifier THS4509 2-3 → Pulls up the pin (normal operation or amplifier is ON); 1-2 → Grounds the pin (low-power mode or amplifier is off)
Table 2-6 EVM Analog Input Options
EVM OptionsEvaluation GoalJumper Changes RequiredVoltage on J9 and J11Analog Signal to ADCComments
1Evaluate ADC performance using direct input to ADC.Install: R84, R94, R97, R98; Remove: R82, R95, R96, R99, R106Do not connectFrom J6Default
2Evaluate ADC performance using input through THS4509Install: R95, R96, R99, R106; Remove: R82, R84, R94, R97, R98J9 → 5V, J11 → GNDSignal from J6 is amplified by THS4509Used if input signal requires amplification.