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LMH34400: how to get the gain over 200kV/A with an additional amplifier?

Seongjin Bak
Prodigy 110 points
Part Number: LMH34400
Other Parts Discussed in Thread: THS4541

LHM34400 - 92dBΩ at 100MHz

PD - Responsivity 1 A/W, Capacitance 2.5 pF and BW 1GHz

Is it possible to get the gain over 200kV/A with an additional amplifier?

Requirements

1) 200kV/A

2) Single ended output

3) Bandwidth at least 100MHz

If there are something else to achieve this requirements using TIA and amplifier in 4 channels, please let me know.

  • +1
    TI__Mastermind 25705 points

    Hello Seongjin, 

      Thank you for sharing the photodiode characteristics. You may use the LMH34400 as the first stage, and increase the gain in the later stages. The LMH34400 has an integrated gain of 40kV/A, after this TIA stage, you may use any amplifier that would satisfy the remaining gain to bandwidth requirement, which in your case would be 5V/V remaining gain at a bandwidth of at least 100MHz. 

       Do you have a load requirement at output of second stage (what will amplifier be driving or interfacing)? Otherwise we can filter to match LMH34400 power supply or by noise and DC specs. And in that case, what is the desired output voltage range for your design?

    Best Regards,
    Sima

  • 0 in reply to Sima Jalaleddine
    Prodigy 110 points

    Hello Sima,

    Thanks for your kindness.

    The amplifier at the second stage will be connected to fully differential amplifier, TI THS4541, and analog-to-digital converter, TI ADC34J4x, in sequence.

    I hope this information helps you choose the amplifier.

    Best regards,

    Seongjin Bak

  • 0 in reply to Seongjin Bak
    TI__Genius 17306 points

    Hello Seonjin,

    Thank you for your response.  My team and I will work to update you with amplifier recommendations.

     Best,

    Alec

  • 0 in reply to Alec Saebeler
    TI__Genius 17306 points

    Hello Seongjin,

    Do you need more help on this topic?  

    Best,

    Alec