Pic24f

[poppy2008]

HI
we are using PIC24FJ64GA004 microchip IC in our power supply,the operating voltage of this IC is 2v to 3.6v. while testing our engineers apply 5v instead of 3.3v ,some IC's failed, some not failed. why some ics not failed, can i use these ic's again(is any thing damaged internally). as an electronics engg i dont have that much knowledge in microcontrollers.pls help me

 

[Nameless1]

What you seeing is very typical. Much depends on the process technology and normal process variations. Most suppliers will spec parts with max Vdd = 3.6V, but do always build some guardbanding into the process, so that in reality parts can operate at higher voltages, eg 5V.

Parts will generally fail because of EOS, electrical over stress. This results in damage to the very thin gate oxides rupturing (punch through) and then transistor fails.
What about the parts that do not fail? Well, the engineer must carry the risk. Much depends on how long they were exposed to the higher voltage. They will have been stressed beyond the manufacture's recommended operating conditions, and there could be a real risk that parts may fail somewhere down the line.

Analogy is much like hunting an animal. Best is to shoot it dead. The wounded animal may continue walking for days before it drops dead. Or it may recover and live for a long time.

 

[poppy2008]

thank you somuch, very nice example

 

[ESchemainda]

Dead components

I think most components in your power supply do tolerate more than 3.3V. For instance usual CMOS IC like CD4xxxx, 74HC... and so on are operational up to 10 Volts and more. In doubt, take a look into the appropriate datasheet. For most ICs you wil get the datasheet from the Internet. Google with: component datasheet.
Good luck.

 

[csaba911]

" as an electronics engg i dont have that much knowledge in microcontrollers.pls help me

Why you call yourself "electronics engineer"........

 

[poppy2008]

what do you mean? (i am a fresh electronics engg),if u know the answer reply , ok send some c sample codes(i know little assembly language ,i dont know anything about c, pls tell me easy way to write 'pic c 'codes)

 

[Nameless1]

wow this seems to be a popular request throughout the forum recently
I just did a basic C course and found it better than assembler *waits for something to be thrown at myself*
Why not go onto www.microchip.com/rtc and look for a regional training centre for your location...the courses aren't that long