Why Two pairs of CAN_H and CAN_L going into One CAN Transciever ?

Started by learn 7 years ago2 replieslatest reply 7 years ago101 views
TJA1145T_FD Transceiver.pdfAttached is CAN Transceiver Datasheet. This IC is wired in our Microcontroller based Electronic Control Unit.

CAN_A_H1 and CAN_A_L1 are connected to CANH and CANL of Transceiver.  Also, CAN_A_H2 and CAN_B_H2 are connected to same CANH and CANL ?
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Reply by waltxFebruary 16, 2017
can bus is a multi drop connection. the tranceivers' outputs  are wired in parallel, so in this cse there are two other can bus devices connected to the can bus device in question.
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Reply by matthewbarrFebruary 16, 2017

CAN bus is a bus just as the name implies, transceiver CANH and CANL pins are all directly connected in parallel with a termination at each end of the bus. The two external connections are probably used for point-to-point attachment to adjacent control units or to a 120 ohm termination at each end:

    T--CU----CU-- ... --CU--T

On the CAN bus Wikipedia page there is a nice picture of how CAN bus transceivers and terminators are connected.