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What is the limitation to the bus length and transmission rate of CAN?

Latest Updated:10/29/2005

Question:

What is the limitation to the bus length and transmission rate of CAN?

Answer:

The CAN protocol has no limitation to the specification for the physical layer, however, the bus length and transmission rate are determined by the network load or bus architecture in the application system. Some associations to certify CAN or the standard based on CAN (for example, ISO, SAE or Device Net) specify the physical layer.

[ Reference Data]
Conditions:

  1. Using shielded cable (5ns/m, impedance : 120 ohm at 1MHz)
  2. Using a transceiver IC which supports ISO11898 Network type: Bus-type (with terminator resister) Cable length: refer to following table
Cable length (m) Transmit rate (kbps)
500 125
250 250
100 500


[Reference data for automotive harness] (specifications may differ according to model and manufacturer)

(1) Power train system
Item shielded cable twisted cable
Cable length less than 40m less than 100m
transmit rate 250kbps to 500kbps 125kbps or lower
Transceiver supporting ISO11898 supporting ISO11519-2


(2) Body System
Item twisted cable Single cable
Cable length less than 100m less than 100m
transmit rate 125kbps or lower 10kbps or lower
Transceiver supporting ISO11519-2 supporting J2411
Suitable Products
R8C/22
R8C/23
M16C/6N4, M16C/6N5
M16C/6NK, M16C/6NL, M16C/6NM, M16C/6NN
M16C/1N