AD9265 cmos clock driver

How can i interface AD9265 with CMOS single ended clock driver without using transformer ?

do i need a clock driver ? actually i am driving my clock from FPGA cyclone V.

Do you have any design file which interface this adc to cyclone V ?

What differential amplifier should i use for single ended analog input (AD8375/AD8370/ADA4938) ?

  • 0
    •  Analog Employees 
    on Jul 1, 2017 1:34 AM

    You can drive the clock input single ended. All you need to do is AC couple the inputs as shown in the data sheet.

    That being said, the AD9265 gets the best performance with differential input.

    You can drive the clock from the FPGA, but I highly discourage this. The FPGA output will have terrible jitter performance which will affect the converter. A clean clock source should be used.

    If you are ok with the performance hit from a low-quality clock source (AKA FPGA), you can use the AD9515 for the CMOS driver. 

    I do not have any design files for this converter, but I can take a look at your Verilog when you are ready.

    What is your input signal like? This will help me narrow down the list. 

  • My signal is IF signal at 10.7MHz, which can go -50dBm to 0 dBm.

    I am thinking to use AD9650 instead of AD9265.

    to convert single ended to differential i am planning to use ADA4938.

    I will add 10dB gain by using ADA4938.

    How much max gain ADA4938 can provide ?

    for clock, I am generating clock through CDCM6208 which is having low jitter.

    Now can you suggest me, shall i use balun or transformer after the ADA4938 (before the ADC analog input) ?

    for clock input to adc, shall i use balun too ?

  • Do you suggest me any other low jitter clock generator which can generate 42.8MHz clock from 50Mhz clock oscillator ?

    what about AD9550 ? can it generate 42.8MHz from 50 MHz oscillator ?

  • 0
    •  Analog Employees 
    on Jul 6, 2017 1:20 AM

    The ADA4938 is characterized up to a gain of 5. I would not recommend using it for a gain of 10dB. The LT6406 is a good choice. It is lower noise, lower power, and it can be set to a gain of 10dB. You can connect the LT6406 directly to the ADC. No balun is required when the common mode is set to the ADC's common mode.

    The AD9550 has a good jitter spec for your frequency range. As for the 42.8 MHz from 50 MHz, you can get close, but I'm not sure which combination of integers will make exactly 42.8 MHz. I did a quick calculation, and I was able to get 42.74 MHz with divide by 5 , R = 1, N=389, p1 = 1, p2 = 91.  Agin, no balun is required for the input as long as you stay within the input spec.

    As for the clock source, the CVHD-950 oscillator is what I recommend. 

  • I want to generate 42.8MHz exact clock from clock generator. can you suggest any Clock generator which is SPI controlled and can generate 42.8 MHz and can be interfaced with AD9650 ,and it should have 4 clock out,it should be cheaper too.