Author Topic: 10uf tantalum capcitor adxl375  (Read 858 times)

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Offline Vindhyachal.takniki

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10uf tantalum capcitor adxl375
« on: January 20, 2015, 08:49:29 pm »
1. Adxl375 specifically mentioned about using 10uf tantalum capacitor on Vs.
2. What the reason for that?
3. What if I use 10uf ceramic for that.


I have read on internet thet ceramic has below drawbacks:
1. Aging
2. Voltage coeff
3. Piezeo noise
4. Flex crack (most severe)


After reading I guess since adxl375 is used for measuring accelration so most dominating reason to use 10uF tantalum will be piezo noise. Is it right?
But along with 10uF tantalum, datasheet specify to use 0.1uF ceramic also, which may go opposite to my above reason.
I want to know what exactly the reason for using tantalum here.
 

Online T3sl4co1l

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Re: 10uf tantalum capcitor adxl375
« Reply #1 on: January 21, 2015, 07:58:21 am »
Tantalum provides supply damping due to ESR.  An acceptable substitute may be a ceramic capacitor of the same value, in series with a chip resistor of a few ohms (to replace the internal ESR of the tantalum).

Exact values depend on what else is connected to the supply as well.

Tim
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Electronic Design, from Concept to Layout.
Need engineering assistance? Drop me a message!
 

Offline wraper

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Re: 10uf tantalum capcitor adxl375
« Reply #2 on: January 21, 2015, 01:18:08 pm »
Tantalum provides supply damping due to ESR.  An acceptable substitute may be a ceramic capacitor of the same value, in series with a chip resistor of a few ohms (to replace the internal ESR of the tantalum).

Exact values depend on what else is connected to the supply as well.

Tim
Few ohms would make it more like electrolytic cap ESR, not tantalum. Unless there is ceramic capacitor unfriendly LDO nearby to this capacitor (low track resistance), no issues with using ceramic as it is. If going to use Y5V or Z5U type, do not forget that they change capacitance drastically with temperature and applied voltage. X7R is far from ideal too, especially when applied voltage is more than half of rated, depends on actual capacitor model though.
 


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