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OPA2835 max gain per channel?

Johnson Cheah
Intellectual 1300 points

Other Parts Discussed in Thread: OPA2835

Hi Team,

What is the max gain can go per channel? In total combine both amp, what is the max gain?

Thanks.

  • 0
    TI__Genius 12631 points
    Hello Johnson,
    For a voltage feedback amplifier like the OPA2835, the key spec is Gain Bandwidth Product(GBWP). What this means is that the Closed Loop BW * Gain = Constant. For the OPA2835 for small signals, the GBWP = 36MHz. So for example, if you desired a BW of 1MHZ, the maximum gain you could have would be 36V/V. If your BW desired was 10MHz, then the max. gain is 3.6V/V before which you will see signal attenuation. There are circumstances, such as using very large value feedback resistors (>2kOhm) where some 2nd order effects start to dominate and this relationship may start to deviate a little. You can use TINA Spice to model your circuit prior to building it on a board.
    -Samir
  • 0 in reply to Samir Cherian
    TI__Intellectual 1300 points
    Hi Samir,

    Is this refer to each channel gain or total gain? Customer is using OPA2835 which is dual channels.
    Currently they are looking on total of 38dB gain. They would like to split on 22dB & 16dB for each channel. It's for audio application.
    -Johnson
  • 0 in reply to Johnson Cheah
    TI__Genius 12631 points
    Hello Johnson,
    You can easily use each amplifier channel with the 22dB and 16 dB gains. With 22dB gain you will get an effective BW of around 4MHz which is 2 decades above the audio BW so you will still get excellent distortion performance. Can you please let me know if this is going to be on the transmit or receive side of the audio signal chain? We can take this offline from E2E and discuss reference designs that our team is currently working on in order to help support the customers application.
    -Samir