Figure 3-3 shows the phase error relative to the average phase within one LMX1204 device across the 4 channels. Within a single device, the phase response is very consistent across each of the channels. Based on information from the LMX1204 data sheet, the expected skew between channels in one device is less than 2 ps. In this case, there is variation within the device in addition to tolerance variations within the output traces and RF cables.

Figure 3-3 Phase Error Across Channels of one LMX1204 Device