Hello
I have any question for bypass capacitor of VDD.
1. Do you have a guide on the value of the bypass capacitor of VDD?
2. What is the maximum value of the bypass capacitor of VDD?
3. Is there any side effect if I increase the bypass capacitor's value?
Best regards.
Hello Louis,
Thanks for reaching out!
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1) Regarding a guide on bypass capacitor sizing, please reference this application note: Section 3.1.1 - Sizing the Bypass Capacitor
But, typically, an 0402 100nF along with a 1uF to 4.7uF capacitor it is a safe bet. It is important to place the capacitors across the VDD and GND pins as close as possible to the IC; with the 100nF being closest to the IC and the larger capacitor next to that.
Also, keep trace length minimal and traces wide, to improve the noise filtering. These capacitors support high peak current being drawn from VDD during turnon of power MOSFET
2) There technically not a "maximum" value of VDD capacitor, but there is reasoning for having smaller and larger capacitors:
- Smaller capacitors, such as the 100nF capacitor; helps filter out high-frequency noise
- Larger capacitors, such as the 1uF capacitor, helps support lower-frequency noise
(ensure to use ceramic, low ESR capacitors)
3) If you only have one, large bypass capacitor, you may not be filtering out the higher frequency noise / transients.
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I hope this answers your question! If so, please press the green button; otherwise, please feel free to follow up!
Thanks,
Aaron Grgurich
