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I have my CAN configuration as shown in the below drawing(automotive application),enter image description here the uC that I’m using has both the CAN controller and the physical layer transceiver built-in so I don’t need a transceiver outside the uC. I have a doubt regarding the common mode choke, I have read that the common mode choke will degrade the signal, below is the link to the question where this is stated  Are Common Mode Choke Coils needed on USB? 1) I would like to understand how the signal degradation can be evaluated, I'm trying to select a common mode choke for CAN network with 500kbps baud rate and want to know things I have to consider while choosing a common mode choke. I understand that there will be some delay in the signal, but is there any way to theoretically calculate this time by simulation ? Or is testing required ?

2) Below is the link to an application note by TI, titled “Common Mode Chokes in CAN Networks: Source of Unexpected Transients”, which states that “extremely high transient voltages that maybe generated by the inductive flyback during a short circuit of a CAN bus line to a dc voltage.” Should I test my circuit during short circuit conditions to see the voltage that the uC pins will see. http://www.ti.com/lit/an/slla271/slla271.pdf

3) Apart from EMC tests, is there any other electrical test that I can conduct to look at the effects that the common mode choke has on my circuitry.

4) I also want to see the effect the capacitors C2, C3 and diode D1 has on the circuitry during ESD pulses. Is there a ESD pulse model available in LTspice and is it possible to simulate and see the results in Ltspice ? Is it feasible to do this ?

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  • \$\begingroup\$ The best part meets the best specs for Ingress susceptibility, egress , Bus current, cost and short cct protection \$\endgroup\$ – Tony Stewart EE75 Mar 10 '20 at 1:08
  • \$\begingroup\$ I'd just pick a part designed specifically for CAN. Murata has several of these, for example. \$\endgroup\$ – Lundin Mar 10 '20 at 7:53
  • \$\begingroup\$ @TonyStewartSunnyskyguyEE75 are they any tests that I can conduct excluding EMC tests. Would it make sense to conduct the short circuit test like in ti.com/lit/an/slla271/slla271.pdf . \$\endgroup\$ – Nidhi Mar 10 '20 at 8:56
  • \$\begingroup\$ @TonyStewartSunnyskyguyEE75 are they any tests that I can conduct excluding EMC tests. Would it make sense to conduct the short circuit test like in ti.com/lit/an/slla271/slla271.pdf and compare the levels of transients for two common mode chokes and select the part with lower levels of transient voltage ? \$\endgroup\$ – Nidhi Mar 10 '20 at 9:02
  • \$\begingroup\$ Yes there are tests for each specified criteria you need. But where are your specs? \$\endgroup\$ – Tony Stewart EE75 Mar 10 '20 at 13:48

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