what are the specifications of a transimpedance amplifier that is used in a li-fi reciever ?

Discussion in 'Analog & Mixed-Signal Design' started by tia2017, Mar 23, 2017.

  1. tia2017

    Thread Starter New Member

    Mar 23, 2017
    23
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    hi ! my thesis is about designing a thigh frequency transimpedance amplifiers. Tia is used in optical communication links.to convert the current from photo-diode to voltage . i searched a lot for specifications of a Tia that is used in Li-Fi but i got nothing. can anyone help me ? and i have another question how can i download full description for OC-192 standard ? its a standard for optical links for 10Gbps speed. i saw it in a paper that i uploaded here but i couldn't find the original reference. thanks for your attention.
     
  2. Kris@UA

    New Member

    Apr 29, 2017
    18
    1
    Hi, For Lifi systems TIA of texas instruments OPA 857/ 656 were used in some research papers. TIA bandwidth for Lifi is low compared to other standards because using Lifi low data rates were reported. You can refer to papers on IEEE that discuss the design of receivers for VLC. I suggest yo to read the data sheet for OPA 857. You may not find TIA exclusively designed for Lifi. Most TIAs are designed for all optical communications but it is their bandwidth that decides their application. By the way I am working on VLC systems and had great difficulty in finding TIA for my high bandwidth application.
     
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  3. tia2017

    Thread Starter New Member

    Mar 23, 2017
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    hi thanks I just saw the answer . how much bandwidth do you need for your application ?
     
  4. tia2017

    Thread Starter New Member

    Mar 23, 2017
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    by the way I read the data sheet for OPA 857.it says that its bandwidth is about 100 mega hertz. it seems really odd to me because in TIAs in vlc that I saw have the bandwidth in the range of GHz.
     
  5. Janis59

    Active Member

    Aug 21, 2017
    699
    107
    For this aim for sure is proved that most best results may be generated NOT by a opamps BUT by discrete two-transistor circuit. That was publication of few years old from Ukraine what shown that allows to capture and identify the one separate electron flowing at wire, what even at case of more than advanced 7721 opamap is 60 fold less sensitive. Thus, they was of course used the ultra-low noise bjt but in your case there is no problems to spit on the noise but instead to buy a 40 GHz smd bjt~s.
    The core of idea is the negative loop resistor. Apply it and get the input impedance just what you like.
     
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