Rise-time (PDA 2017.07)
Rise-time measurement on 2019-12-16. BNC-cable to 4 GHz LeCroy oscilloscope, DC 50 Ohm termination, 10%-to-90% rise time measurement result is <700 ps. The 1PPS output uses five parallel outputs of the clock-buffer, driving about 2.7V into a 50 Ohm load and 3.3V into 1 MOhm.
Output-to-output time difference measured with Keysight 53230A counter. Measurements done before any tuning with the trimmer-capacitors. After tuning it is possible to achieve <10 ps output-to-output skew. The delay from the input to any output has not been measured accurately, but it should be around 15 ns (to be verified).
- PDA2017.01 With input going to LT1711 comparator triggering at 1.0 V (set by reference ADR423). This edge is buffered by 74AC14 before 1:8 fan-out to output-stages with three 74AC04 inverters in parallel driving the outputs.