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Topic: Switching power sounds noisy (Read 1 time) previous topic - next topic

James C4S

Did you use ceramic caps, if so what were their temperature coefficient (X7R, Z5U, etc.)
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0miker0

I have a voltage divider set for 5 volts. A fixed one would probably save me two resistors. The part is hand soldered using a microscope so the components GND pad under the part is not soldered to the board. Pins #4 and #9 are both GND and run to the center GND pad on the boards so I just hand solder those two pins.

0miker0

I used ceramic caps and just used whatever temperature type I could find since it will always be in a room temperature environment. Most likely X7R type. Nice. Thats something I never though of. I'll check that out as well.

James C4S

#8
Jan 09, 2013, 05:11 pm Last Edit: Jan 09, 2013, 05:19 pm by James C4S Reason: 1
All class 2 and 3 dielectrics will sing.   X7R and X5R the least.  Z5U and Y5V the worse.

Switch to a "better" (if you aren't already using X7R) dielectric or go to the highest rated voltage you can.  
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kf2qd

You may not be loading the power supply enough. 1 amp and 40mA is quite a difference. The power supply may want a little more load.

The other problem is that the power supply may not be running at a high enough switching frequency. A good switching supply runs at frequncies outside the range of human hearing.

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