Post Go back to editing

AD74412R routing inquire

Category: Hardware
Product Number: AD74412R

Hi Sir,

Now we are designing the layout,

but due to PCB room spacing problems, the SENSELF, SENSEL, SENSEHF, SENSEH of AD74412R will have a I2C signals passing through, but it will be separated by the GND plane, the thickness is about 7.6mm, could this interfere with the analog signal (SENSE) at this case?

Thanks.

Parents
  • Hi Sir,

    There might be complex answer to your query. I would like to clarify this topic, before give you an answer.

    AD74412R have SPI signal to communicate with micro, is your I2C signal related to different bus and communication other than AD74412R? 

    Concerning your PCB stack up, I understand, there is only one GND layer between top (SENSE signals) and I2C signals? Please confirm. 

    By thickness 7.6mm, you mean route width? 

    I addition related to layout, please follow carefully all the recommendations given in AD74412R datasheet (page 50 - www.analog.com/.../AD74412R.pdf).  

    Best regards,

    Arnost

  • Hi Arnost,

    1. Because we have another's chips on the PCB, thus the I2C signal is used for MCU control the thermal sensor.

    2. I use a 6 layer stack-up PCB as follwing,

    6L stack up

    I am not sure if the sense pin will be interference even L2 is the GND layer.

    and the spacing is about 7.6mm between L1 to L3 (PP:2.45mm+L2:1.2mm+core:4mm)

    Thank you.

  • Hi Sir,

    thank you for provided details. 

    Risk of interference is low, however have in mind we never done this. I2C buses in general tends to be slow signals. (Note: AD74412R communicates via SPI, which might operate on much higher frequencies.)

    What I can recommend is to keep SENSE pins as much away as possible by your design. GND plane in between should help. You might consider even placing your I2C signal on layer further away from SENSE signals. 

    Hope this answers your question. 

    Let me know, if you have any more queries. 

    Best regards,

    Arnost

  • Hi Sir,

    no problem. Pleasure to answer your queries. 

    Best regards,

    Arnost

Reply Children
No Data