Post Go back to editing

ADL5304

Category: Hardware

Hi, 

I need to use the ADL5304 to amplify the current of a photodiode.

I want to use the 200 dB range because I need to amplify very low light level.

I have a problem with Vlog, it is not linear between -90 and -66 dBm. I think this problem is due to the dark current of the photodiode but I can't find how to fix it.

Can you say how we can compensate the dark current of the photodiode using the evaluation board of ADL5304?

Parents
  • Hi cecile,

    First may I suggest using oscilloscope to check the ADL5304 output, not just DVM. Often these types of problems are due to external AC noise sources finding their way into the high-Z PD connection node into the ADL5304. Also consider probing VNUM and VDEN nodes to make sure those nodes are relatively low noise also. 

    If noise is not a major contributor of error, the ADL5304 output should be quite accurate. Consider using the on-chip PD bias circuitry with IMON pin as a way to help reduce PD dark leakage. For some rather unique applications, the on-chip PD bias circuitry may not be good enough and a more specialized custom PD bias circuit could be necessary. 

Reply
  • Hi cecile,

    First may I suggest using oscilloscope to check the ADL5304 output, not just DVM. Often these types of problems are due to external AC noise sources finding their way into the high-Z PD connection node into the ADL5304. Also consider probing VNUM and VDEN nodes to make sure those nodes are relatively low noise also. 

    If noise is not a major contributor of error, the ADL5304 output should be quite accurate. Consider using the on-chip PD bias circuitry with IMON pin as a way to help reduce PD dark leakage. For some rather unique applications, the on-chip PD bias circuitry may not be good enough and a more specialized custom PD bias circuit could be necessary. 

Children
No Data