DAC output oscillation

[lbtroy]

Hi all,

I found out that the source of the oscillation of my current steering DAC output (at the DAC end not the filter end) comes from the pad inductor(2nH). Just from a conceptual standpoint, how do you get rid of the oscillation? (which component I touch should help to cure the oscillation?)

Also the off chip passive filter that is connecting to the offchip resistor has a high Q...wouldn't that cause ocillation anyway?

I have the circuit attached. Thank you in advance!

 

[FvM]

The term oscillations is vague somehow. I guess, you are talking about ringing ín the transient response?

What do you mean with "pad inductor"? Bond wire inductance? 2 nH sounds unsuitable high for a high speed device.

Also the off chip passive filter that is connecting to the offchip resistor has a high Q.

The transient response of a filter is a design parameter. I presume you have designed it according to your application requirements. I would expect a low-Q filter for a DAC used with pulse waveforms, e.g. Bessel or Gaussian. A known bond wire inductance should be considered in the filter design, however.