The GTM transceiver Quad requires three analog power supplies: GTM_AVCC at a nominal voltage level of 0.8 VDC, GTM_AVCCAUX at a nominal voltage level of 1.5 VDC, and GTM_AVTT at a nominal voltage level of 1.2 VDC for Versal ACAPs. The pins for each of these analog power supplies are tied to a plane in the package. In some packages, there are two planes (a left plane and a right plane) for each of the analog power supplies. See Board Design Guidelines for a discussion of the internal power planes in the GTM transceiver packages.
Noise on the GTM transceiver analog power supplies can cause degradation in the performance of the transceivers. The most likely form of degradation is an increase in jitter at the output of the GTM transmitter and reduced jitter tolerance in the receiver. Sources of power supply noise are:
- Power supply regulator noise
- Power distribution network
- Coupling from other circuits
Each of these noise sources must be considered in the design and implementation of the GTM transceiver analog power supplies. The total peak-to-peak noise as measured at the input pin of the Versal ACAP should not exceed 10 mVpp over the frequency range of 10 kHz to 80 MHz.