Understanding 'C Code' & 'No.' in Buck Converter Regulator Datasheet

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Discussion Overview

The discussion revolves around the interpretation of the terms "c code" and "No." as used in a buck converter regulator datasheet, particularly in relation to selecting specific capacitors. Participants seek to clarify these terms and understand how they relate to manufacturer datasheets for capacitors.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant expresses confusion about the meaning of "c code" and "No." in the context of a buck converter regulator datasheet and seeks clarification on how to find corresponding capacitors from manufacturers.
  • Another participant suggests a website that might provide more information on capacitor markings but acknowledges uncertainty in relating it to "c code."
  • A different participant requests a link to the specific datasheet for context, indicating they have not encountered the term "C code" before.
  • One participant speculates that the "c code" may pertain specifically to surface mount capacitors.
  • Another participant shares a link to a capacitor datasheet and hypothesizes that the terms may refer to case size and termination type, suggesting further investigation of other manufacturers' datasheets.
  • One participant proposes that the terms might indicate options for capacitor configurations based on different manufacturers and their physical sizes or equivalent series resistance (ESR).
  • Another participant clarifies that the datasheet organizes capacitor selection by inductance, implying that the "c codes" and numbers refer to specific capacitor values used in example circuits.
  • Several participants note the presence of footnotes in the datasheet that may explain the meaning of the numbers.

Areas of Agreement / Disagreement

Participants express varying interpretations of the terms "c code" and "No." with no consensus reached on their exact meanings. Some suggest possible explanations while others seek further clarification.

Contextual Notes

Participants acknowledge the need to refer to the specific datasheet for accurate context and understanding of the terms discussed. There are indications of missing assumptions regarding the definitions of "c code" and "No." as well as the implications of capacitor selection based on inductance.

Mzzed
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I have recently come across a datasheet for a buck converter regulator that uses the terms "c code" and "No." for certain capacitors but when going to the manufacturer datasheets for these capacitors they make no reference to any "c code" or one single number for a capacitor. If anyone could help me understand what these mean and how to find these specific capacitors from the manufacturers capacitor datasheet I would really appreciate it. The image bellow is where I have been reading these terms.

upload_2017-7-23_12-34-40.png
 
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maybe this reference is more complete:

http://www.robotoid.com/appnotes/electronics-capacitor-markings.html
 
Thanks I did see this website before however I'm not sure how to relate that to C code or the single digit number. The closest thing to C code was the letter that gives tolerance but it's definitely not that.
 
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Mzzed said:
I have recently come across a datasheet for a buck converter regulator that uses the terms "c code" and "No." for certain capacitors

I have never heard of that C code
can you please link to the specific datasheet you were looking at so we can see the context
in which they are referred to
 
The title of the chart mentioned surface mount capacitors so the code may be valid for that only.
 
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I looked up that Sprague 594D series capacitor's datasheet.

http://www.vishay.com/docs/40002/293d.pdf EDIT WRONG LINK
use

https://www.vishay.com/docs/40006/594d.pdf

They pack a lot of information in them so you have to acquire a knack for reading tech writers' minds...

I think they're using those two characters for case size and termination type.
capacitorcode1.jpg
Perhaps you can study the AVX and KEMET datasheets to support or refute my hypothesis ?

It's curious your source sorts capacitors by inductance...
upload_2017-7-23_20-16-44.png


just how credible are those folks ?

old jim
 
Last edited:
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jim hardy said:
It's curious your source sorts capacitors by inductance...
LOL :smile:
 
I suspect it just giving you options. For example if the voltage is 7v and you fit a 33u inductor then you fit...

Two capacitors in position C2 if using AVX capacitors or
One capacitor in position C3 if using Sprague or
Two capacitors in position C4 if using Kemet.

This might be necessary if the caps are physically a different size and have a different ESR.

But I might be wrong.
 
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  • #10
Sorry I should have included the entire datasheet for the buck converter regulator : http://www.ti.com/lit/ds/symlink/lm2678.pdf

The datasheet sorts the capacitor selection table by inductance because they are recommending certain capacitor values depending on the inductance you have chosen to place on the output of the circuit.

CWatters said:
I suspect it just giving you options. For example if the voltage is 7v and you fit a 33u inductor then you fit...

Two capacitors in position C2 if using AVX capacitors or
One capacitor in position C3 if using Sprague or
Two capacitors in position C4 if using Kemet.

This might be necessary if the caps are physically a different size and have a different ESR.

But I might be wrong.

It would have helped if I had linked the datasheet in the first place but I believe the c codes and number refer to a specific capacitor value as they choose some for part of an example circuit.

Thanks for all the responses though, they are much better ideas than what I had come up with myself haha
 
  • #11
If you look at the footnotes for that table you will find the meaning of the numbers.

BoB
 
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  • #12
rbelli1 said:
If you look at the footnotes for that table you will find the meaning of the numbers.

BoB
Yeah sorry I discovered I made a mistake and there's actually a table at the beginning of the datasheet that gives the values hahah
 

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