3 Replies Latest reply on May 15, 2020 3:53 AM by BragadeeshV_41

    Layout review for CY8CMBR3106S

    YSJE_3566666

      Hello.

      My customer is going to apply touch buttons for their product with CY8CMBR3106S.

      Could you please review the attached files?

       

      I think it would be better to rotate IC because of touch trace path and vdd line.

      Also, CS15 should be connected to VDD.

       

      Please let me know if there are any changes required.

       

      <product Information>

      - FPC (thickness : 0.3mm)

      - Overlay : Polycabonate (thickness : 0.5mm)

       

      Thanks and Regards,

      YS

        • 1. Re: Layout review for CY8CMBR3106S
          BragadeeshV_41

          Hi YSJE_3566666,

           

          Please find the comments below:

           

          Schematic:

           

          CS15/SLD24[3] should be connected to VDD.

           

          Layout:

           

          1. Since you are using a FPC, it is recommended to connect the hatch pattern to shield and not to ground. Connecting the hatch pattern to ground in a FPC design will cause Cp to increase and might go beyond acceptable range of 45 pF

           

          2. The buttons are placed very close to one another. The optimum button to button to gap is 8 mm. Please be aware the touching inbetween two sensors will trigger both the sensors. But if this is not possible, we highly recommend you to use the Flanking sensor suppression feature to avoid false triggers (hoping that multi touch performance is not required)

           

          Please build a prototype of the design to check if the design meets all your requirements before going for production.

           

          Regards,

          Bragadeesh

          1 of 1 people found this helpful
          • 2. Re: Layout review for CY8CMBR3106S
            YSJE_3566666

            Hello, Bragadeesh.

            Thanks for your kindly support.

             

            1. I will connect the hatch pattern to shield. I need advice about distance or space. Please check below.

                 a. distance between button to shield (0.5mm) on top side.

                 b. trace width (0.17mm) on bottom side.

                 c. distance between touch trace to shield (0.3mm) on bottom side.

                 d. is there a recommendation of distance between touch trace to touch trace?

             

            2. I think the button to button space doesn't matter. Multi touch is allowed in our application.

             

            Thanks and Regards,

            YS

            • 3. Re: Layout review for CY8CMBR3106S
              BragadeeshV_41

              Hi YSJE_3566666,

               

              Thanks for the update!

               

              1. Button to shield electrode can be 1 mm (minimum)

              2. Trace width is okay

              3. Trace to shield clearance can be 0.25 mm (minimum)

              4. Trace to trace clearance can be 0.25 mm (minimum)

               

              Regards,

              Bragadeesh

              1 of 1 people found this helpful