Lucast85
Member level 3
Hi all,
I'm using a daisy chain communication for board to board communication between battery management systems. The environment could be very noisy (industrial/automotive) and the producer of the ICs (AD7284) reccommend to use a filter on the center tap of the transformer used to isolate the signal.
The following image illustrate that:
I understand that the noise will be mainly a common mode noise and the filter will short the noise from the two lines towards the chassis of the board (ground). The evaluation board uses this transformer.
I see that frequently was used a 75ohm resistor and a 1nF (2.5kV) capacitor for ethernet communication.
I think this is a similar application but...
P.S. This is all the datasheet write about the transformer:
I'm using a daisy chain communication for board to board communication between battery management systems. The environment could be very noisy (industrial/automotive) and the producer of the ICs (AD7284) reccommend to use a filter on the center tap of the transformer used to isolate the signal.
The following image illustrate that:
I understand that the noise will be mainly a common mode noise and the filter will short the noise from the two lines towards the chassis of the board (ground). The evaluation board uses this transformer.
I see that frequently was used a 75ohm resistor and a 1nF (2.5kV) capacitor for ethernet communication.
I think this is a similar application but...
- how can I chose the RC components?
- What about the voltage of the TVSs? I think it's correct to use a value between the voltage of useful signal on the primary side of the transformer and the absolute maximum rating of the communication pins of the IC. I'm right?
P.S. This is all the datasheet write about the transformer:
Thank you allThe center point of the isolated sides on the transformer can connect to the chassis or be left unconnected. If connected to the chassis, ESD protection diodes and an RC filter to filter noise from the chassis may be required.
RT is the terminating resistor for the transformers; use values from 50 Ω to 200 Ω.
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