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.

LMG1020: some questions about LMG1020 & TIDA-01573 & GAN & peak power measurement

Part Number: LMG1020
Other Parts Discussed in Thread: OPT8241, CSD16301Q2, , SN74LVC2T45, TIDA-01573

We are developing indirect lidar and Direct lidar. I have some questions in terms of ti  lidar components.

 1. it is possible to get higher peak current  when use gan and gate driver.

   We aready reviewed your lidar evm board using opt8241 , 9221.

   I want to get depth data for long distance. (12Mhz ~ upto 3Mhz , duty 50%)

   So i try to change serveral below patrs . because I think gan is getting higher peak current than FET with gate driver.

     -   Gan(epc2040)  instead of FET ( CSD16301Q2 ) 

     -  gate driver (Lmg1020)  instead of sn74lvc2t45

   Could you plz check  my trial is proper or not  for getting higher peak current .

2. how to get peak current  in higher freqency and long duty using TIDA-01573.

  As you mentioned in datasheet (TIDA-01573 ,figure3.) this driver can get 50A for 2ns.

   But  i need faster frequency and long duty cycle .  ( 2M , 100ns, duty 20%)

  If i lower temperature of laser enough, can i drive laser up to 50Apk ?  what if i caculate peak current ?  it's possible?

  I think laser peak current  is depend on duty cycle .

 You can make any recomandation for our requirement (freq : 2M, pulse width : 100ns, duty 20%).

3. The way measure peak current of laser.

  If i use detector ( thorlabs DET08C)  and optical power meter ( Thorlabs PDA150A) .

  Can i calulate peak power from measured power and proportion of laser.

  Below list  is  light modulation  information

  duty : 20% / freq : 2M / LD Peak power : 40W

thank you.

 

  • Hi kyeongmin choi,

    Thanks for asking about LMG1020. Im an apps eng and will help out.

    Using 1020 instead of sn74 will allow higher peak currents due to lower drive impedance to charge the GAN fet capacitive load. The GAN fet should reach higher peak current since it has a smaller package inductance and lower Rdson for equivalent IV ratings. They also run cooler with better thermal conductivity than silicon The main reason, the peak current capability surpasses Silicon is due to the higher intrinsic carrier density and electron mobility.

    To achieve higher peak currents, layout should be most important - check out the 1020 datasheet layout guidelines and let me know if you have any questions. To measure the peak power, RX, we are using one light sensor from Thorlabs to detect the light energy and pulse width (the purpose of this is not to measure distance).

    1) The energy per pulse would be found with avg-power / pulses-per-second

    2) The Peak power per pulse would then be the energy-per-pulse / pulse-width 

    Does this answer your question?

    Thanks,

  • Hi Jeffrey Mueller.

    Thanks for your reply.

    Could you please give me model name of thorlabs's sensor ?  I need that sensor.

    thanks

  • No problem! let me know if you have any more questions.

    Thorlabs - DET08C

    you can check out the TIDA-01573 user guide and find out more about it here
    www.ti.com/.../tidue52.pdf

    Thanks,
  • How about my question 2 ?

    please let me know what happen peak current is when we raise frequency up to 2Mhz and expand pulse width upto 100ns.

    thakyou
  • Hi Kyeongmin,

    LMG1020 peak drive strength is independent of pulse width. With close VDD cap placement 2Mhz can be easily achieved.

    Thanks,