AD8099 oscillation

Hi,

I use AD8099 as the output buffer of the AD768, for getting a ±1.1V output voltage. Specific circuit is in the attachment.

When I test this circuit, I found AD8099 is oscillating. Is there any suggestion to eliminate the oscillation of AD8099?


In addition, I notice that, said in the datasheet of AD8099, compensation network values depend on the gain. In my circuit, how many I should regard the gain as?


Thank in advance for any help.

linweixiu

SCHEMATIC.pdf
Parents
  • dillian,

      You are using an op amp that is three times higher gbw than the AD811 on the eval board.

    Faster is not always better.  I would use ADA4895-1, ADA4897-1, ADA4891-1 instead of

    the AD8099.

      With any high speed op amp, you need two bypass caps on each supply pin, right next to

    the part.  Your schematic shows no caps.

    It's extremely difficult to breadboard with high speed parts;  I would do a quick four layer board.

    Harry

Reply
  • dillian,

      You are using an op amp that is three times higher gbw than the AD811 on the eval board.

    Faster is not always better.  I would use ADA4895-1, ADA4897-1, ADA4891-1 instead of

    the AD8099.

      With any high speed op amp, you need two bypass caps on each supply pin, right next to

    the part.  Your schematic shows no caps.

    It's extremely difficult to breadboard with high speed parts;  I would do a quick four layer board.

    Harry

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