ADuM7441CRQZ Speed issue

Unable to reach communication speed 25Mbps. Our testing just can go until <7Mbps only. 

Based on the datasheet shown below, the speed can go up to 25Mbps. 

Kindly advise. 



Updated the schematic drawing for the connection
[edited by: John pg at 1:58 PM (GMT -4) on 8 Sep 2020]
  • 0
    •  Analog Employees 
    on Sep 8, 2020 1:46 PM

    Hello John,

    There are two elements to throughput, the ability to pass a pulse, and the propagation delay.  How are you using the part?  Is it for SPI communication?  If so, the propagation delay will limit the speed of the bus.  If you are sending a serial stream of data in one direction, then the minimum pulse width will limit the data rate.

    How are you using the part and how are you measuring throughput?  We have many parts that will address different aspects of data rate.  

    Best Regards,

    MSCantrell

  • Hi MSCantrell, 

    Yes for SPI communication use. 

    I uploaded the 2 parts connection in main post. May I can share you via email? 

  • 0
    •  Analog Employees 
    on Sep 8, 2020 8:17 PM in reply to John pg

    The prop delay on this device is 40nS, the SPI MOSI line response has to arrive back at the controller by the next clock edge, so there is a minimum delay of 80nS between when data was clocked out and the MOSI line is ready to be read at the master, a bit more for the data to be clocked out an trace delays etc.  You have a few options,

    1) the ADuM3151 SPIsolator, it provides fast prop delays for operation up to17Mbps as well as three extra low speed channels for housekeeping signals.

    2) ADuM3150 SPIsolator which will operate up to 40Mbps SPI bus using a delayed clock output and it provides 2 extra low speed channels.  This required extra hardware support from the controller.

    3) ADuM141E0B which has a 14nS prop delay so it should be able to operate at 25Mhz with no issues.

    The second chip requirements depend on how fast the signals need to be.  And those functions may move to the primary chip if the speed requirement is low.

    I hope this helps,

    MSCantrell

  • Hi FormerMember

    Appreacited the assist and guideline. 

    Yes, we duplicated it and isolated to the same root cause. 

    Now we applied sample and will working out option#3. 

    Thanks again.