When a Signal Hits The End of a PCB Track – What happens? | Reflections by Eric Bogatin

Ringing caused by reflections can be fixed. What is happening and what to do? Explained by Eric Bogatin. Thank you Eric.

– Software used in the video: https://www.bethesignal.com/bogatin/vrpw3016-yoshi-animations-reflections-p-1072.html
– Signal Integrity Academy (use FEDSI – 3 months free): https://www.bethesignal.com/bogatin/3monthsubscription.php
– FEDEVEL courses: https://courses.fedevel.com/

00:00 Understanding reflections
01:06 Electrically Short vs. Long
02:52 The tool we are using explained
03:48 Simulating: Electrically short
08:04 Reflections on classic CMOS and standard board
10:41 Simulating: Electrically long (e.g. DDR3 / DDR4)
15:16 50 OHM impedance is not 50 OHM resistance
16:39 Simulating a buffer example
18:32 Why we get reflections
20:37 What happens when there is a reflection
25:44 Why reflection disappears
30:08 Frequency of ringing
31:49 How to eliminate reflections
35:37 Signal level change caused by termination
39:25 Source termination