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Regarding choosing of correct SMD Capacitor for PCB Assembly

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#73873

Regarding choosing of correct SMD Capacitor for PCB Assembly | 5 May, 2015

hi everyone,

I have done with my PCB Prototyping. I need to Prepare a Bill of Materials(BOM) for my PCB Assembly.

I have one doubt regarding selection of SMD Capacitor.

-My Question is

For Example, I have to use 0.1uF capacitor on my PCB board.In Datasheet, It is mentioned that Recommended Max.Voltage Rating is 4V.

So, while searching for the Capacitor with

-Value = 0.1uF

-Max.Volatage = 4V

-Mounting Type = SMD

-Package = 0805

I am able find the capacitor with 0.1 uF, 0805 Package and SMD with Max.Volatage = 6.3V but not with 4V.

----"So, Can I use this 6.3V Max.Volatge rating Capacitor in place of 4V Max.volatage capacitor or not"?----

Regards

Anirudh THABJUL

Hardware Engineer, Lansa Diffusion, Paris, France

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#73875

Regarding choosing of correct SMD Capacitor for PCB Assembly | 5 May, 2015

Yes overrating in electronics is basically OK underrating , you are looking for trouble.

sarason

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#73878

Regarding choosing of correct SMD Capacitor for PCB Assembly | 5 May, 2015

Thankyou once again dude.

Please Don't mind it.

I have one more doubt regarding the Max.Power Rating of SMD Resistor.

---"Is same principle which you told application for Maximum Power rating Of SMD Resistor also"?---

i.e

Higher Powerrating is not a problem But Lower Power rating is A problem.

Regards

Anirudh THABJUL

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#73895

Regarding choosing of correct SMD Capacitor for PCB Assembly | 8 May, 2015

Hi

dont play whit cap substitute ,you may screw up the whole design ,many ceramic decoupling cap was sensitive to applied voltage and temperature specially true for X5R and Y5V type. so a 4V cap may have right capacity at 3.3V but a 6 volt cap will have 70% less capacity and fail later in field

http://www.murata.com/en-global/products/emiconfun/capacitor/2012/11/28/en-20121128-p1

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#73897

Regarding choosing of correct SMD Capacitor for PCB Assembly | 9 May, 2015

Might I add, avoid Y5V if you want a reliable design and Marc is correct do look at those charts for X7R voltage dip under load, if you are doing low volume, save yourself the trouble and time, just overrate.

sarason

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#73898

Regarding choosing of correct SMD Capacitor for PCB Assembly | 9 May, 2015

Might I add, avoid Y5V if you want a reliable design and Marc is correct do look at those charts for X7R voltage dip under load, if you are doing low volume, save yourself the trouble and time, just overrate.

sarason

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#73899

Regarding choosing of correct SMD Capacitor for PCB Assembly | 9 May, 2015

Hi

few year back i design a board for a customer then build pre-production run on my in house line ,all was good then the customer for going into production what to save few $ move to my competitor for assembly this was in late fall then in summer phone ring here ,all of the production board was erratic one the hot summer day ,but pre-production unit work ? ,after long investigation we found that the competitor for save money have swap X7R cap for Y5R ,at 20deg all work but once Board reach 40-50deg cap de-rating fall 80% off and MCU start to be erratic ,customer lost it gov contract and got huge penalty ,and now it stay here it forgot the competitor ..

also on some switching supply ESR was also critical for CAP

so trust me not play whit cap that designer put on a BOM anb if make a change re-qualify the design for make sure it still meet the specification before production run stat

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