Coin size batteries on circuit boards used for?

Discussion in 'General Electronics Chat' started by SamEricson, Apr 27, 2015.

  1. SamEricson

    Thread Starter Member

    Apr 25, 2015
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    I often see Coin size batteries on circuit boards

    What kinds of IC chips are these coin size batteries for?

    I have seen coin size batteries 3vdc for NVRAM, but what is on NVRAM chips mostly? the settings or bios?

    The coin size batteries get low in voltage and often need to be replaced. Once you replace it with a new batteries don't you have to load or burn the code back into the NVRAM chip?
     
  2. absf

    Senior Member

    Dec 29, 2010
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    On a PC motherboard, it was for the RTC to keep the clock from running when the PC is off.

    On a musical keyboard that I repaired, it was used keep the setting of the registration like tempo, instruments, rhythms etc on a cmos ram chip.

    Allen
     
  3. SamEricson

    Thread Starter Member

    Apr 25, 2015
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    RTC is a real time clock chip. The RTC chip is a CMOS chip or RAM chip not sure why it needs power if its just a crystal

    What kinds of CMOS RAM chips need a coin size battery?

    Were they NVRAM chips?
     
  4. absf

    Senior Member

    Dec 29, 2010
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    Below are some pictures of the RTC with battery attached fro the Arduino and the backup battery for the digital piano next to the 32 pin DIP chip.

    Allen
    RTC top.JPG RTC bottom.JPG technics piano battery.jpg
     
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  5. tranzz4md

    Member

    Apr 10, 2015
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    I'm pretty sure absf meant " to keep the clock ->RUNNING<-". In any case, yes, you need and want a battery to keep your PC system knowing what time it is, even when it gets turned off by it's integral power switch, or by other power disconnecting means. Don't get too goofy about NVRAM, CMOS, NMOS, etc., think about the bigger picture. You can keep a clock working just fine without a UPS, battery bank, and engine generator.
     
    absf likes this.
  6. MrCarlos

    Active Member

    Jan 2, 2010
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    Hello SamEricson

    You Asked:
    What kinds of IC chips are these coin size batteries for?
    Chips are those who may lose their internal information when they are interrupted electricity.

    You Asked:
    I have seen coin size batteries 3vdc for NVRAM, but what is on NVRAM chips mostly? the settings or bios?
    Could be. If it is a PC mother board. But it could also be what mentioned You absf in his message #2. (Musical keyboards).

    You Asked:
    The coin size batteries get low in voltage and often need to be replaced. Once you replace it with a new batteries don't you have to load or burn the code back into the NVRAM chip?
    Yes, you have to reload or burn the code in those chips.

    You Say:
    RTC is a real time clock chip. The RTC chip is a CMOS chip or RAM chip not sure why it needs power if its just a crystal.
    The RTC, usually are CMOS family and have an internal memory to 'Remember' the time of day. Some other memorize the date too.
    And it's not just a crystal but is the Chip(RTC) and a crystal oscillator.

    You Asked:
    What kinds of CMOS RAM chips need a coin size battery?
    All those types that require preserving its internal information, regardless of being disconnected from the main electrical energy.

    In other words: If the Chip loses the data contained in when the power is removed and NOT want this to happen, there will use a battery of the type that is appropriate. Whether: Coin battery size, size A or double-A, Etc. Some systems have rechargeable batteries.

    Now, if you want to know the identification number of chips that could use those batteries You may found on this link: http://www.alldatasheet.com/ Asking in Description.


    .
     
  7. ScottWang

    Moderator

    Aug 23, 2012
    4,850
    767
    RTC - Real Time Clock, It was made by crystal + time generator + cmos ram + CR2032(battery)
    You can get the answer from Nonvolatile BIOS memory and its linking page.
     
  8. dl324

    Distinguished Member

    Mar 30, 2015
    3,211
    619
    Any chip/circuit that needs to retain volatile memory and/or continue operating when power is off.
    It depends. Some things (like calculators) use two sets of batteries, so you can replace one or the other, but not both at the same time. Some circuits use a capacitor to maintain memory while the battery is being replaced. Some NVRAM have built-in batteries and they're no longer non-volatile when the battery dies. Dallas Semiconductor sells several sizes of NVRAM with non-replaceable batteries. They're spec'ed for 10 years; which is the shelf life of many lithium coin batteries. Some equipment uses a cap/super cap to maintain volatile memory during brief power failures.

    Xicor manufactures NVRAM that is RAM backed by EEPROM. They detect falling VCC and automatically back up RAM to EEPROM; but the power supply needs to provide low VCC for a minimum time. When those devices power up, some automatically copy the contents of EEPROM to RAM. Normal operations are from RAM. RAM has "unlimited" read/write cycles, EEPROM has limited write...
     
  9. SamEricson

    Thread Starter Member

    Apr 25, 2015
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    But what other types of IC chips need a battery besides NVRAM? and RTC?
     
  10. Brevor

    Active Member

    Apr 9, 2011
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    That question was answered by Mr. Carlos in post #6

     
  11. SamEricson

    Thread Starter Member

    Apr 25, 2015
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    Yes I know but he didn't tell me what kind or type they are? all i know is NVRAM and RTC chips
    What other types of chips so i know what to look up
     
  12. Brevor

    Active Member

    Apr 9, 2011
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    Those are the only kinds I can think of.
     
  13. #12

    Expert

    Nov 30, 2010
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    Who told you there ARE other kinds of chips that need backup batteries?
     
  14. SamEricson

    Thread Starter Member

    Apr 25, 2015
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    0
    How do you get the code from a NVRAM chip? because if I remove the NVRAM chip from the circuit board it will lose it's code

    You use a universal programmer to burn code into NVRAM chips, but they will loose the code once you remove it from the universal programmer so how do you burn the code into NVRAM chips while it's soldered into the circuit board with a new battery installed?
     
  15. #12

    Expert

    Nov 30, 2010
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    New Thread.
     
  16. SamEricson

    Thread Starter Member

    Apr 25, 2015
    196
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    ok i will make a new thread for the topic
     
  17. MrCarlos

    Active Member

    Jan 2, 2010
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  18. SamEricson

    Thread Starter Member

    Apr 25, 2015
    196
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    So which CMOS chips need the coin size battery I'm confused
     
  19. BillB3857

    Senior Member

    Feb 28, 2009
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    And the circle comes all the way around.
     
    #12 likes this.
  20. tranzz4md

    Member

    Apr 10, 2015
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    SAM! The only "chips" that "need" the "batteries" (usually cells, not batteries) are ones that somebody WANTED to have constant or backup power to -> for a SPECIFIC task<- !

    Tell us what you want done, or what the system designer of a specific system was trying to do, and we'll say "yep, a battery (or cell) is what you'd want there!
     
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