Capacitor Flexibility with Voltage

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Hi All

 

I have a design that uses the following TANT capacitor on the input of a Li-Poly Charger(LTC4162IUFD)

T491X157K020AT7027 by KEMET Corporation | Capacitor Tantalum Solid | Arrow.com

 

It is rated to a max 20V,

 

Usually, this PCB is powered between a max of 12-17V.

 

I have a circumstance where I need to connect to a power source that is 24V.

 

What effect could this have?

 

 

 

This topic has a solution.

Thanks

Regards

DJ

Last Edited: Tue. Mar 30, 2021 - 03:36 PM
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djoshi wrote:
What effect could this have?

 

 

 

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Not could, will. Tants are not very tolerant.

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Also, from the Datasheet:

 

https://static6.arrow.com/aropdf...

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  3. Wrong baud rate is usually due to not running at the speed you thought; check by blinking a LED to see if you get the speed you expected
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Suggest you choose another cap with a higher voltage rating, 30v or higher for this app.

 

Jim

 

 

(Possum Lodge oath) Quando omni flunkus, moritati.

"I thought growing old would take longer"

 

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Thanks

 

I will change the cap to a high rated version.

Thanks

Regards

DJ

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And your safety factor depends upon just how clean / stable the 24 V supply will be.

 

Also, be sure to consider the temperature range the device will operate in, and if the selected cap's parameters change, for better or worse, over the intended range of operation.

 

Good luck wiht your project.

 

JC

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ki0bk wrote:
Suggest you choose another cap with a higher voltage rating

Usually you want a factor of two margin for something like that.  The humidity can be a factor with tantalums too.  They don't do well in places like Florida.  Tiny cracks in the coating can lead to catastrophic failure.  Hooking one up backwards for even a few seconds will require replacement, I learned the hard way.  A lot of people won't use them since they like to burst into flames, but I use a lot of them because they are small, and I went on a buying binge some years ago and have a lot of them.  It is probably better to avoid tantalum if you can if you can get the size and ESR you want with other kins, plus they are expensive.  Some linear regulators specify tantalum. 

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MarkThomas wrote:
Hooking one up backwards for even a few seconds will require replacement,

 

Brand new vision mixer, just installed for testing. Power turned on. Phone call from maker - don't turn it on... popopopopopopop, oops too late. One hundred and sixty off tants installed backwards by the pick and place machine... took a while to replace them all.

 

Neil

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Used to be ceramics topped out around0 0.22 uF or maybe  0.47 uF, at least for reasonable $$$...nowadays ceramic caps in the low uF range are cheap & creep into tantalum land

 

https://www.electronicproducts.c...

 

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

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barnacle wrote:
One hundred and sixty off tants installed backwards

Ouch!

 

Back in the days when a one megabyte memory was a large board, with lots of chips on it (all socketed), I had a colleague who put all the chips in backwards.

 

And they were not just any memory chips - they were high-speed, military static RAM chips ...

 

Verily, there was weeping & wailing & gnashing of teeth!

 

surprise surprise surprise 

Top Tips:

  1. How to properly post source code - see: https://www.avrfreaks.net/comment... - also how to properly include images/pictures
  2. "Garbage" characters on a serial terminal are (almost?) invariably due to wrong baud rate - see: https://learn.sparkfun.com/tutorials/serial-communication
  3. Wrong baud rate is usually due to not running at the speed you thought; check by blinking a LED to see if you get the speed you expected
  4. Difference between a crystal, and a crystal oscillatorhttps://www.avrfreaks.net/comment...
  5. When your question is resolved, mark the solution: https://www.avrfreaks.net/comment...
  6. Beginner's "Getting Started" tips: https://www.avrfreaks.net/comment...