AD8016 Digital and Analog Ground Pins/Packages...

Hello,

I have a medical customer here in town that is using the AD8016AREZ6 within their design.

They are currently looking into the excessive distortion and incorrect gain being exhibited by the device and have asked me to investigate why the SOIC package has eight analog grounds plus a digital ground, while the TSSOP package that they are using only has the one digital ground?

I was hoping you guys could provide some background as to why the analog/digital ground pins are different on the two packages.

Thanks in advance for your help.

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  • Hi Mike,

    Thank you for providing additional information. I tried simulating the differential amplifier configuration as in the Figure 41 of the AD8016 datasheet with the the same feedback and gain resistors as your customer. The simulation worked well though. You mentioned that they found a mistake with the bias level and corrected it. Did this mean they corrected by operating at full on? Did your customer tried using other AD8016 chips to see whether the problem is with chip or with the board?

    As for the questions you raised, AD8016 should be capable of driving an output of 40Vpp at 10MHz into a 200 ohms load without a transformer at a +/-12V supply. The 200ohms load draws 100mA peak current which is well within the 600mA linear output current rating of AD8016. Looking at the pictures you sent, I don't think that the output is slew rate limited as the signal looks more of a sine wave than a triangle wave (as what happens on slew rate limited sine wave).

    Regards,

    Neil

Reply
  • Hi Mike,

    Thank you for providing additional information. I tried simulating the differential amplifier configuration as in the Figure 41 of the AD8016 datasheet with the the same feedback and gain resistors as your customer. The simulation worked well though. You mentioned that they found a mistake with the bias level and corrected it. Did this mean they corrected by operating at full on? Did your customer tried using other AD8016 chips to see whether the problem is with chip or with the board?

    As for the questions you raised, AD8016 should be capable of driving an output of 40Vpp at 10MHz into a 200 ohms load without a transformer at a +/-12V supply. The 200ohms load draws 100mA peak current which is well within the 600mA linear output current rating of AD8016. Looking at the pictures you sent, I don't think that the output is slew rate limited as the signal looks more of a sine wave than a triangle wave (as what happens on slew rate limited sine wave).

    Regards,

    Neil

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