• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 2 answers
  • Subscribers 46 subscribers
  • Views 688 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

The ADC input voltage problem about ADC12D1600RFRB

user4770612
Prodigy 40 points
Other Parts Discussed in Thread: ADC12D1600, LMH5401, LMH5401EVM, WAVEVISION5

Hi

I buy a ADC12D1600RFRB. I saw the adc12d1600 Datasheet .the Electrical Characteristics: Analog Input/Output and Reference,I noticed when NON-EXTENDED CONTROL MODE,the VIN_FSR  minimum voltage is 540 mvp-p and the maximum voltage is 660 mvp-p.The picture as the following :

 The input voltage range makes me very confused,  the voltage range is 540 -660mvp-p or 0-540mvp-p and 0-660mvp-p?But my input voltage is about 0-200mvp-p,if the voltage range is 540 -660mvp-p,how do I make it works for me ? 

Looking forward to hear from you.

sincerely,

Jiaxiang

  • 0
    TI__Mastermind 43930 points

    Hi Jiaxiang

    If your signal is single ended and 0 to 200mV you should use an amplifier to add gain and to perform single-ended to differential conversion. You could do this with something like the LMH5401EVM. You will need to configure that amplifier EVM so that the output signals meet the Vcmi (input common mode) requirement of the ADC EVM, and so the output common mode voltage of the amplifier EVM is centered between the positive and negative power supply voltages. Please refer to the LMH5401 datasheet, and in particular the application circuit shown in Figure 70 for more information.

    I hope this is helpful.

    Best regards,

    Jim B

  • 0 in reply to Jim Brinkhurst1
    Prodigy 40 points

    Hi Jim B

    I am so sorry to reply you so late,I bought the LMH5401 EVM,but how should I configure the EVM  to VCMI mode? I saw the LMH5401 datasheet ,as the figure 70 shown,The LMH5401 EVM 's Vcm Pin should  be connected to which part of the ADC board?  Does the CM mode need to an external voltage source connect  the CM pin?Another problem, when I use the ADC EVM ,the ADC chip is very hot ,does this affect the performance of the EVM  kit? If affect ,what should I do? Can I add a heatsink or fan to the ADC chip?

    Looking forward to hear from you.

    Sincerely,

    Jiaxiang

  • 0 in reply to user4770612
    TI__Mastermind 43930 points

    Hi Jiaxiang

    The LMH5401EVM VCMI should be connected to VCMO, which is available at pin 9 of J17 and pin 9 of J15.

    You will also need to change the ADC from AC-coupled mode to DC-coupled mode. The default configuration has VCMO connected to ground at TP5 and pin 9 of J15. The shorting jack between TP5 and J15 pin 9 should be removed when using a DC-coupled signal source.

    The ADC will get hot in normal operation but shouldn't need a heat sink. In the Wavevision5 GUI, one of the Register sub-tabs on the right side of the GUI shows the ADC, FPGA and PCB temperatures. The ADC temperature should stay below 95C in normal operation.

    Here is an example of the temperature readout sub-tab from a similar ADC in WV5.

    I hope this is helpful.

    Best regards,

    Jim B