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TDC7201: Do TDC7200 or TDC7201 have a mode suitable for SPAD(TCSPC)?

user6371294
Prodigy 10 points
Part Number: TDC7201
Other Parts Discussed in Thread: TDC7200,

Hi,

We want to make a Lidar based on SPAD chip. For SPAD, TCSPC algorithm has been widely used. In these cases, TDC chips or blocks are always implemented on FPGA or integrated in sensor chip. Now, we want to use a discrete TDC chip because we just need a single channel Lidar.

I read the datasheet, 7201 has a "Multi-Cycle Averaging" function. However, for TCSPC, we want to get all the data, not the average value. I also saw this topic.

https://e2e.ti.com/support/sensors/f/1023/t/606193?tisearch=e2e-sitesearch&keymatch=TDC7201%25252525252520max

Maybe I can try to reach the max readout rate. However, I don't know the max rate now and this method wastes some time on communication.

Do you have some related experience?

Thanks,

Gong Ma

  • 0
    TI__Mastermind 27940 points

    Hi Gong,

    The choice between TDC7200 and TDC7201 is primarily dependent on your required measurement range. Both devices support

    • Individual Mode 1: 12 ns to 2000 ns
    • Individual Mode 2: 250 ns to 8 ms

    but only the TDC7201 supports

    • Combined Operation: 0.25 ns to 8 ms

    Our system solutions teams have primarily used the TDC7201 for LiDAR based designs, so I recommend the TDC7201 if you are seeking a proven solution such as the Reference design maximizing transimpedance bandwidth for LIDAR and time-of-flight (ToF) applications (TIDA-060025). Beyond this TI Design, we have no test data or experience on LiDAR applications.

    The Multi-Cycle Averaging method is optional. You can read back all the single point data per measurement, but as you've noted, the limiting factor in how fast you can read this data out is determined by the SPI communication clock and number of bytes read per measurement. Using the maximum supported clock rate of 25MHz will minimize the communication timing overhead between measurements.