Reading a CMOS imaging sensor

Discussion in 'General Electronics Chat' started by fsonnichsen, Oct 12, 2017 at 11:38 PM.

  1. fsonnichsen

    Thread Starter New Member

    Jun 6, 2013
    18
    2
    I am finding to my surprise that the linear CCD arrays that were provided by companies like SONY and TAOS are now discontinued and vanishing from the market. All are being replaced by the CMOS type linear arrays. I had no problem implementing circuits and PIC software to read the CCD which basically presents itself as a shift register. However I am finding little of nothing on the CMOS type regarding how to read it. The datasheets for Hamamatsu and others basically only give specs. I know the process is much more complex and apparently requires Mhz readout design.

    Can someone point me to a source of information to get started with circuit design for implementing a CMOS linear array?

    Thanks
    Fritz
     
  2. WBahn

    Moderator

    Mar 31, 2012
    20,221
    5,747
    It's going to depend heavily on the imager -- or more specifically the read-out IC (ROIC). I've designed ROICs for several CMOS imagers (including Hamamatsu) and the interfaces vary quite a bit. They are often embedded in a larger system (sometimes a multichip module) and the external interface is then dictated by whoever did the wrapper. This is often done because CMOS imagers tend to have a lot of fixed-pattern noise and the corrections are often done in this wrapper.
     
  3. fsonnichsen

    Thread Starter New Member

    Jun 6, 2013
    18
    2
    Thank you. Having the ROIC search word is a help. I am looking at Hamamatsu since my work is in spectroscopy but for some of my simpler implementations their CMOS linear PDAs seem expensive ($200 vs $12 for the old CCDs that I used). It looks like my simple goal (read the pixels) has just become a lot more complicated and expensive. Add to this that I am not yet convinced the CMOS will improve SNR in the UV and NIR regions. I have calls into teledyne E2V and DALSA for pricing and a teleconn with Hamamatsu today so I will ask them more about the ROICs used in their product.
    Unfortunately I assume that spectroscopy is a very small share of the market and we have leveraged our designs off of the linear CCD for some years riding on it's more conventional uses. Now with CMOS this symbiosis has vanished. At this time big vendors like Ocean Optics have continued rights on the remaining SONY IX511s (while they last) but I expect that in the next few years costs will go up and possibly quality go down in the world of spectroscopy as a result of the "advances".

    Thanks again
    Fritz
     
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