ADN4670 Serial Interface

I want to use ADN4670 in my project but I have 3 questions about its functionality.

1) According to the datasheet, ADN4670 receives 12 bits through serial communication to program the device. So I need to push to high the EN pin, generate clock and send 12 bits of data, and then push to low the EN pin. But in my situation, the DSP that will communicate with ADN4670 can only send 8 bits or 16 bits of data (through SPI). My question is if I can use 16 bits instead of 12 bits. Push to high the EN pin, generate clock and send 16 bits of data (12 bits with data and 4 bits with 0), and then push to low EN pin.

2) I want to use 4 ADN4670 in parallel, i.e. they must be configured with the same data, at the same time. Can I connect the CK, SI and EN pin of all 4 ADN4670 together?

3) ADN4670 is a clock driver. But my signal is not exactly a clock. In one case it is a clock of 250kHz for 500us and 0 for another 500us. And in other case it is just a 2us pulse, which will be repeated after 1ms. Will it work properly?

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  • +1
    •  Analog Employees 
    on Mar 22, 2019 4:05 PM

    Hi Campelo,

    Sorry for the delay in responding, I needed to check this in more detail.

    1) This should work, but the valid data needs to be the first 12 bits, and there's a small chance you might need the remaining four bits to be the next 12 bits you would want loaded next time (more likely the shift register is reset though by EN low).

    2) Should be fine as long as the micro you are using has enough output drive/can drive what will be equivalent to ~30k Ohm pull-up or pull-down (four 120k in parallel)

    3) ADN4670 will work fine for other LVDS signals, not just pure clock.

Reply
  • +1
    •  Analog Employees 
    on Mar 22, 2019 4:05 PM

    Hi Campelo,

    Sorry for the delay in responding, I needed to check this in more detail.

    1) This should work, but the valid data needs to be the first 12 bits, and there's a small chance you might need the remaining four bits to be the next 12 bits you would want loaded next time (more likely the shift register is reset though by EN low).

    2) Should be fine as long as the micro you are using has enough output drive/can drive what will be equivalent to ~30k Ohm pull-up or pull-down (four 120k in parallel)

    3) ADN4670 will work fine for other LVDS signals, not just pure clock.

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