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Original question:

DAC61416: Assistance Required for DAC61416 Configuration in Varactor Diode Biasing Circuit

DAC61416: DAC60096IZEB

Meghla Maji
Prodigy 100 points

Part Number: DAC61416
Other Parts Discussed in Thread: DAC60096,

Tool/software:

Hi,

for this same application can I use DAC60096IZEB (96 channel) which will reduce the no of DACs requiired.

In the datasheet it is given DAC60096IZEB is a unbuffered one. what does this signify? what are the advantages and disadvantages of using DAC60096IZEB ?

--

Regards,

Meghla

  • 0
    TI__Mastermind 42253 points

    Hi Meghla,

    The attached forum post was using a 0 to -12V output. The DAC60096 only supports up to -10.5V. 

     A buffered output provides a higher current rive ability, and a low output impedance. The DAC60096 has a 41k output impedance and cannot support 25mA load drive like the DAC61416. We never got specific requirements from you so it is hard to say if either device will work, or which would be the best option. 

    Best,

    Katlynne Jones

  • 0 in reply to Katlynne Jones
    Prodigy 100 points

    Hi Katlynne, 

    Thanks for the response. We want to drive a 16x16 array having varactor diode with negative voltages. we can work till -10V also. As DAC61416 is having only 16 outputs for 16x16 array we would need 16 DAC61416. So we thought of going with DAC60096 as it is having 96 outputs. But outputs of DAC60096 is unbuffered whereas outputs of DAC61416 is buffered. What will be the exact differences in their outputs ? 

    In case we go with DAC60096 do we have to use opamps at the output to make it a buffered output ?

    --

    Regards,

    Meghla 

  • 0 in reply to Meghla Maji
    TI__Expert 6670 points

    Hi Meghla,

    Yes, you have to use a op-amp for each of the DAC output of the DAC60096 to driver the varactor diode. As Katlynne mentioned, the DAC60096 has a 41k output impedance and cannot support 25mA load drive like the DAC61416. 

    Please add your DAC output driver needs to help you better.

    Thanks,
    Sanjay

  • 0 in reply to Sanjay
    Prodigy 100 points

    Hi Sanjay,

    We require 0 to -10V output voltage with nA current as the varactor will work in reverse bias. in that case can we use unbuffered DAC60096 output without opamps=?

  • 0 in reply to Meghla Maji
    TI__Expert 6670 points

    Hi Meghla,

    That is okay but still you need to make sure that 41k output impedance will not affect the varactor diode biasing. Please do the analysis for V/I bias across conditions and based on that you can take a call. I wouldn't recommend the DAC60096 without the buffer. 

    Let me know if you need any other help in this case.

    Thanks,
    Sanjay