I am troubleshooting a new design using a DS90UB913A/914A combination with a single-ended coax connection and am seeing boards that will not indicate "lock" of the serial link.
Of four devices only one appears to establish the serdes link. I measured the DC resistance to 1.8V and it indicates 50 ohms and also I have 50 ohms to ground on the negative leg of the serial pair. One difference between my circuit and the datasheet recommendations is right now I have 0.1uF cap on the negative leg rather than 0.047uF. Is that possibly causing signal integrity issues?
One other data point is the operating device shows an offset voltage of 1.5V (approx.) on the serial line whereas the other devices are reading 1.8V.
