ADRF6703 Lo input level

Hi,

I have a question.

Q: According to the data sheet, Lo input level = 0dB typ

    Is it possible to present the Min value?

   

Lo input source is another ADRF6703 for synchronization.

Because it is Typ 0.1 dBm as the spec of LO out, it attenuates by a few dB considering cable loss of LO out and loss due to pattern.

Our customers are concerned that synchronization can not be maintained due to a drop in the Lo level.

 

Best regards,

Hiroshi

  • 0
    •  Analog Employees 
    on Oct 10, 2017 5:52 PM

    Hello Hiroshi,

    I am now checking our data system if we have data and number to share. If not, need to check it with few parts. However, minimum external LO input for some other parts at similar architecture was specified down to around -6dBm, even it works below this. There will be some performance variation over LO Amplitude. Please refer to below plots copied from ADRF6720-27(left)  and ADL5375 (right) datasheet. So I expect it would be okay at ADRF6703 as well at that point for LO Input level. Will let you know it soon.

       

    Thanks

    Tony

  • Hi, Tony

    I appreciate very much for your kindness.

    If you provide the data, our customer will be grateful.

    I am waiting for your reply.

     

    Best regards,

    Hiroshi

  • Hi Tony,

    I got the evaluation result of the customer, so I will share the information.

    They confirmed that synchronous output was possible even with -22 dBm input.

    The detail is below.

     

       Each LO input / out  insertion loss : -4.5dBm (MABA-007159 at 4.4GHz from D/S)

       Cable Loss : about -1.5dBm

    Therefore total loss : about -10~-12dBm

    And they added an attenuator to check the limit ~-10dBm.

    So, about -22dBm. they confirmed that the slave is synchronized in this state.

    Is the lower limit at least -12 dBm or less?

    They are waiting for ADI's opinion.

     

    Best regards,

    Hiroshi

  • 0
    •  Analog Employees 
    on Oct 18, 2017 11:50 PM

    Hello Hiroshi,

    Sorry for late and not with actual data yet here. Good to hear for a customer to have a chance to look at and it works even at -22dBm. Previously, when I checked how it could go down at LO Input for ADL5375, it worked away below -6dBm that we specified as min LO level at ADL5375 datasheet .  I can't remember exact number but it was below -15dBm. However, there were some performance degradation at that low level as you can see at the plots and part-part variation. We checked it in -6~+6dBm LO range in characterization for product release process, even though it works out of this range. This is the reason we specify -6dBm for LO min value. We may apply -6dBm for External LO at ADRF6703. Sorry again, let me try to find time to get data in few days.

    Regards

    Tony 

  • 0
    •  Analog Employees 
    on Oct 27, 2017 3:08 AM

    Hello Hiroshi,

    The performance of undesired sideband suppression varies over LO Amplitude but it keeps resonable performance down to -12dBm LO Input power(I checked it down to -12dBm). And other performances(output power, LO feedthrough, HD2, HD3, OIP2, OIP3) keep pretty  constant over LO amplitude. So it looks that it is okay to drive LO level away below typical value (0dBm) like -10dBm. Please refer to the below performance plots. But remember we characterized part at typical LO driving level and below plots are with one part at room temp. There might be part-part variation and also over temp. So it is suggest to drive LO near to typical value but it might be okay to be in -6 ~ +6dBm range that is what other parts specify as min/max value for LO level.

      

    Thanks

    Tony