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Original question:

WEBENCH® Tools/LM22678: LM22678: LM22678TJ-5.0/NOPB Mejor component selection inductor selection query?

WEBENCH® Tools/LM22678: we need help for Switcher output side noise remove

hardik jani
Prodigy 150 points
Part Number: LM22678

Tool/software: WEBENCH® Design Tools

Hello All
We have design Switcher using LM22678J-5 V For 5 A
we need help for Switcher output side noise remove
Please Consider below Component detail which is used
1) Switcher IC Part Number :- LM22678TJE-5.0/NOPB
2) 1st Input Capacitor Part Number :- A767KN336M1JLAE042
3) 2nd Input Capacitor Part Number :- CC0805JKX7R9BB105
4) Booting Capacitor Part Number :- CC0805JKX7R9BB105
5) TVS Diode Part Number :- STPS30SM60SG-TR
6) Inductor Part Number :- 744325650
7) 1st Output Capacitor Part Number :- 16SVPF180M
8) 2nd Output Capacitor Part Number :- C0805C104J1RACTU

Please find below a screenshot of Schematic

Also, I have attached Layout Image 

Image 1 TOP Side

Image 2  Power Side

Image 3 GND Layer

Image 4 Bottom Side

we have issue Face in Output Side Noise present 

kindly find I have attached the image of DSO 

signal measure at Input Capacitor 

 

signal measure at Output Capacitor 

Please suggest how to remove noise at the output side 
Thank you in advance

  • 0
    TI__Guru 72625 points

    It looks like you schematic and layout designations don't match.

    However, there are several improvements that can be made to you layout.

    The input caps must be as close as possible to the device.

    Also, the grounds for the diode, input cap, output cap and the device must all 

    be as close as possible.

    You should also try to connect the ground pin of the device to the case and 

    ground plane on the top layer.

    In general an LC filter on the output of the regulator is a good way to help reduce switching noise on the output.

  • 0 in reply to Frank De Stasi
    Prodigy 150 points

    Hello Frank De Stasi

    Thank you so much for your reply 

    I have updated Schematic photos because we will use two types of switcher in our PCB that's way please review it if any other input or suggestion 

    Thank you for advance  

  • 0 in reply to hardik jani
    TI__Guru 72625 points

    I believe that the points mentioned above are the best starting point.

  • 0 in reply to Frank De Stasi
    Prodigy 150 points

    Hello Frank De Stasi

    Thank you very much for your reply 

    we have to remove Ground FB and we have common ground all Switcher measure voltage on CRO so Flatulation is 0.170 to 0.200 mV

    Thanks for your support

    Hardik Jani

    Embedded Hardware Engineer