Are ADN4696E compatible with ADN4662?

Hello,

    are the ADN4696E/ADN4697E logic level compatibles with ADN4661/ADN4662?

Can I directly connect these 2 devices?

Thanks in advance

Maurizio.

  • 0
    •  Analog Employees 
    on Feb 2, 2012 10:04 PM

    Hello Maurizio,

    These devices are designed for different applications, the ADN4696E/ADN4697E are designed for multipoint LVDS communication (M-LVDS) and the ADN4661/ADN4662 for point-to-point LVDS.

     

    What application would you wish to connect these devices together in?

     

    The following assumptions can be made based on the datasheet specifications, though we have not tested connecting together these devices on a bus.

     

    The ADN4661 does not have a driver enable signal as this is not needed for a point-to-point link. ADN4696E/ADN4697E devices may receive the LVDS signals from the ADN4661 but the lower driver output levels of the ADN4661 would mean that the bus should not be too long or have too many receivers. Any ADN4696E/ADN4697E drivers on the bus would need to be disabled (DE low).

     

    The ADN4662 does not have a valid receiver output state for an idle bus (no active driver). However, if an ADN4696E/ADN4697E is used as an always enabled driver on the same bus, the ADN4662 may receive the LVDS signals.

     

    The digital logic levels on the ADN4661/ADN4662 and ADN4696E/ADN4697E are compatible.

     

    Regards,

    Conal

  • Hello Conal,

         I will try to shrtly explain my application and why this question born.

    I'm designing a board (with ADI BF506F DSP) and I need to connect with others (one at the time) via SPI interface.

    For many reasons this "external" SPI needs to be converted in LVDS.

    Unfortunately my boards can be SPI master or slave (depending on the other external board SPI configurations) so I expect to have bidirectional SPI (and so bidirectional LVDS) for each signal (MISO, MOSI, CLK.....).

    For this reason the ADN4696E seems to be a good choice, but on the others side (boards) are placed ADN4661/ADN4662 devices.

    Can I proceed with my design using ADN4696?

    Thanks a lot

    Maurizio

  • Hello Conal,

        yes, you have correctly understood, this is my scope, and you told me that it should works.

    Thanks a lot for your support.

    Maurizio

  • 0
    •  Analog Employees 
    on Feb 3, 2012 9:28 PM

    Hello Maurizio,

    Thank you for the explanation. If I understand correctly, the board in design may be SPI master or slave (Potentially ADN4696E for the interface) that will connect to one other board (either a master or a slave, with ADN4661/ADN4662).

    Going by the datasheets for these devices, this should work, but contention should be avoided where there is an ADN4661 at the other end of a channel. For example when the new board is connected, have all the ADN4696E devices in receive only mode (DE and /RE low) to begin with.

    If I understand correctly, there would be the following two cases for the new board once it is connected:

    New board is Master:

    SPI signal (as LVDS) New Board (as master) Devices Direction Old Slave Board Devices
    /CS ADN4696E (DE high, /RE high) ---> ADN4662
    CLK ADN4696E (DE high, /RE high) ---> ADN4662
    MOSI ADN4696E (DE high, /RE high) ---> ADN4662
    MISO ADN4696E (DE low, /RE low) <--- ADN4661

    New board is Slave:

    SPI signal (as LVDS) New Board (as slave) Devices Direction Old Master Board Devices
    /CS ADN4696E (DE low, /RE low) <--- ADN4661
    CLK ADN4696E (DE low, /RE low) <--- ADN4661
    MOSI ADN4696E (DE low, /RE low) <--- ADN4661
    MISO ADN4696E (DE high, /RE high) ---> ADN4662

    Regards,

    Conal