• State TI Thinks Resolved
  • Locked Locked
  • Replies 2 replies
  • Answers 1 answer
  • Subscribers 48 subscribers
  • Views 602 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

LMH3401: Designing a Single to Differential ended Op- Amp for High-Speed ADC

Mohamed Aashik S
Prodigy 95 points
Part Number: LMH3401
Other Parts Discussed in Thread: ADC12QJ1600, LMH6555

Tool/software:

Dear team, 

I need to convert single ended to differential signal. 


1. What are the design changes required for single ended input? and how can I give single ended input to the non-inverting terminal? 

2. How can I configure the gain of the Op- Amp? 

3. What are the operating voltages for the op amp if my input is +/- 0.8 Vpp and what voltage should I keep for the Vocm? 

4. Can you please suggest an easy understandable resource to know more about the working and calculations of the Single to differential ended Amplifier? (Highly Important)

My requirement is to give differential signal to High-speed ADC with 1 GSPS. Which ADC can I use for that, and you can also suggest other Fully Differential amplifier for driving the ADC. 

  • 0
    TI__Expert 4550 points

    Hi Aashik,

       LMH3401 can be a good option to drive 1GSPS ADC

    1. Please refer to section 9.3.2 of LMH3401 datasheet

    2. Please refer to section 9.3.2.1 of datasheet. You can also use this calculator.

    3. What is the DC common mode of of your input +/- 0.8Vpp signal? Typically you need to choose supply voltages such that VICM and VOCM are with in the recommended operating range.
    Vocm should be ADC input common mode voltage. You can connect the ADC VICM pin to VOCM pin of LMH3401.

    4. Below are the links to App note and FDA calculator:

         https://www.ti.com/lit/an/snoa953a/snoa953a.pdf

         https://www.ti.com/tool/download/SBOR022

    TI has wide range of > 1GSPS ADCs. You can find the filtered list here and pick one depending on your application. I think ADC32RF5Xcan be a good option.

    Let me know if you have any questions.

    Best Regards,

    Hruday

  • 0 in reply to Hruday Kumar Mudireddy
    Prodigy 95 points

    Thanks for the reply. 

    I need to drive ADC12QJ1600. Does this ADC12QJ1600 has inbuilt differential driver? or we should drive externally. 

    Can I use LMH6555 for converting the single ended to differential signal? for ADC12QJ1600
    Could you please help me in simulation for the LMH6555 circuit? (in TINA TI or LTSpice? )

    Requirements. 

    1. The single ended voltage is 0.8 Vpp. 
    2. The Gain can be set to 1, where I dont want to increase the input signal. 

    And I have another doubt, whether can we use Balun Transformer for driving the ADC12QJ1600? Since, In the EVM, they are using Balun Transformer. But ours is DC Voltage. 
    Please help me with this


    Thanks
    Aashik