Q: DAC power phase noise propagation path

    All the circuits on the chip have to be powered in some way, which gives a lot of opportunity for noise to propagate to the output. Different circuit power supply noise propagation path is also different, the following highlights several common DAC power supply noise propagation path. In the figure below, the DAC output typically consists of a current source and a MOS tube, which directs the current through either a positive or a negative pin. The current source obtains power from an external power source, and any noise is reflected as a current fluctuation.

   1. The noise of the MOS tube current source can reach the output end through the MOS tube, but this only explains the coupling phenomenon of noise.

    To contribute phase noise, this noise also needs to be mixed to the carrier frequency through the MOS tube. The MOS tube here is equivalent to a balanced mixer. 2. Pull-up inductance Pull-up inductance is another noise path that flows from the power supply rail to the output end.