STW TC1 - 10.1.7 CAN

10 Application Notes
User Manual 320/374
10.1.7 CAN
CAN-Termination
According to the CAN specification, every end of a CAN bus trunk-line must be terminated with a 120 Ohm
Resistor.
Example of a terminated CAN bus:
CAN-Bus length (Trunk-line length)
The CAN bus length (Trunk-line length) is limited and depends on the Baud-rate, the CAN bus is operated with.
The following table shall give an overview of maximum CAN bus length according to the used Baud rate.
Baud-Rate [kbit/s]
CAN-bus length
1000 (1MBit/s)
< 20m
500
< 100
250
< 250
125
< 500
50
< 1000
20
< 2500
10
< 5000
Drop-line length
Drop-lines are allowed, but should be avoided, as they typically create signal echo. Drop-lines must not be
terminated with 120 Ohm resistors! The following table shows the maximum lengths of drop-lines to be used:
Baud-Rate
[kBit/s]
Drop-line length
[m]
Total length of all drop-lines
[m]
1000 (1Mb/s)
< 1
< 5
500
< 5
< 25
250
< 10
< 50