Post Go back to editing

LT6233-10, Bandwidth issue

hello all, 

I'm using a LT6233-10  for my project and I try to test it before.

My need is 2MHz bandwith with a Gain at 200 and  enable pin.

I'm facing an issue about the Bandwidth. the schematic is below.

I try to test it as a buffer, it work, I can have the same amplitude until the 2MHz with an input at 1Vpp

Then with this schematic, the signal is cut around 500KHz.

The input is a function generator, HiZ output. 20mVpp with an offset at 1.65V.

Vref = 1.65V

Vcc = 3.3V (I also try 5V, always single supply)

I try with 40 gain.

A also try with a non inverting mouting, same issue.

If I chose a lower gain, 4 for exemple it work.

The datasheet give this amplifier for 320MHz GBW. 

I don't understand where I'm wrong. I test it with LTspice and it work.

please, if anyone see where I'm wrong, con you helpe me please.?

Parents Reply Children
  • Ho thank for your answer. 
    your right about the gain =200. But in my test, I’m with a gain at 40, I must have 8mhz bandwidth, but I don’t event have 1mhz.

    do you have an other ref, the ltc6250 have a consumption too High even in shutdown.

    I need a very low power mode.

    I talk about 2mhz bandwidth to have some marge. But 1mhz , 1.5mhz is ok.

    but I don’t have it yet

  • Hi, 

    Apologies for missing this. Can you specify how low the power mode should be? If there are other parameters important for you application, please feel free to share. 

    There are parametric search for different kinds of amplifiers. Here is the one for rail-to-rail and for low power op amps. Hope this helps.

  • hi sorry for delay, I don't have any notification on your replay.

    with these search, with a high Gain, I always finish with low noise amplifier, which need a low input impedance, whereas my previous stage need a load at 10Kohms min. I don't want to use a buffer (low consumption). 

    So,  lower consumption in use mode (few mA), single powered by 3,3V, bandwith -3dB 1MHz for a 200 gain

    thank for your help