Datasheet

CAN
Transceiver
CANL
CANH
C
SPLIT
CAN
Transceiver
R
TERM
Standard Termination
Split Termination
CANL
CANH
R /2
TERM
R /2
TERM
MCU or DSP
CAN
Controller
CAN
Transceiver
Node 1
MCU or DSP
CAN
Controller
CAN
Transceiver
Node 2
MCU or DSP
CAN
Controller
CAN
Transceiver
Node 3
MCU or DSP
CAN
Controller
CAN
Transceiver
Node n
(with termination)
R
TERM
R
TERM
ISO1050
SLLS983H –JUNE 2009–REVISED JUNE 2013 www.ti.com
CAN TERMINATION
The ISO11898 standard specifies the interconnect to be a single twisted pair cable (shielded or unshielded) with
120Ω characteristic impedance (Z
O
). Resistors equal to the characteristic impedance of the line should be used
to terminate both ends of the cable to prevent signal reflections. Unterminated drop-lines (stubs) connecting
nodes to the bus should be kept as short as possible to minimize signal reflections. The termination may be in a
node, but if nodes may be removed from the bus, the termination must be carefully placed so that it is not
removed from the bus.
Figure 26. Typical CAN Bus
Termination may be a single 120 Ω resistor at the end of the bus, either on the cable or in a terminating node. If
filtering and stabilization of the common mode voltage of the bus is desired, then split termination may be used.
(See Figure 27). Split termination improves the electromagnetic emissions behavior of the network by eliminating
fluctuations in the bus common-mode voltages at the start and end of message transmissions.
Figure 27. CAN Bus Termination Concepts
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