Using ADM306E 5Mbps I'd like to communicate by cable 20m.
But AN-960 When figure 7 is seen, there is 9.14m with the limit in 5Mbps.
Would there be any reform measures?
The approximate delay of standard RS485 cabling is about 5ns/m, and 20m cable will cause ~100ns delay that limits the max data rate to 20Mbps(10MHz). But the figure in AN-960 is a conservative estimation of the data rave vs cable length considering jitter, propagation delay, coding schemes and skew. The cable manufacture gives the cable characteristics and cable length versus data rate for reference. ADM3066E has fast driving rise time and low skew and it might be able to drive the cable(eg. cat.5 twisted) to 20m when implementing the actual communication.
Thank you for your answer
Just adding to this answer, I'm confirmed in the lab that the ADM3066E can transmit and receive data at >32Mbps, across 100m of cable, with the eye width at the receiving device > 80% open. Cable used during the test was single twisted pair of 22 AWG cable. Please see attached plot of eye width at the receiving end. Based on these results the ADM3066E can easily communication for your application, at 5Mbps across 20m of cable.