Using DS1307 tiny RTC module with 3 volts

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Hi,

I am looking to power my Atmega32L from the same same coin cell that is used as battery back up for the Tiny RTC module. Ds1307 datasheet says that required vcc is 5 volts but since I'll be runing my Atmega32 on 3 volts, I won't be able to wake up the RTC module with 3 volts. Is there anyway to power the module with 3 volts.  

Tiny RTC I2C module

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Doge123 wrote:
Ds1307 datasheet says that required vcc is 5 volts but

No buts - the minimum is 5V (well; 4.5, actually)

 

https://datasheets.maximintegrat...

 

But, surely, it can't be hard to find a 3V RTC these days?

 

 

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Ok thanks!!

Last Edited: Wed. Dec 27, 2017 - 05:02 PM
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Doge123 wrote:
Hi, it actually works with 3v.

No - that is wrong.

 

The datasheet clearly states that the DS1307 requires 5V for proper operation.

 

Most of the posts in that other thread are about interfacing it to a 3V device (Raspberry Pi) - not about running it from 3V.

 

For a 1-off hobby project you might get away with running it at 3V - but you should not rely upon out-of-spec operation for a serious design.

 

As this post says, superior replacements that do operate at 3V are available.

 

EDIT

 

Doge123 Has, apparently, edited post #3 and completely deleted the entire content to which I was replying.

Last Edited: Wed. Dec 27, 2017 - 05:08 PM
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Hi, I realized it after I posted my comment, you had not posted anything. So, I edited it so to not confuse anyone who visit this. Seems, you posted at the same time. I stand corrected. 

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No,  I have not tried this.

 

If you remove the Battery,   it might work because VCC > VBAT.

 

However the best solution is to invest £0.99 in a DS3231, DS1302, PCF8563, ... module from Ebay.

 

Personally,  I am very sceptical that anything for £0.99 will contain 100% quality components.

My experience is that the cheap modules "work" but are not 100% accurate.   suggesting that they use crystals that failed QC.

 

David.

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If you are indeed trying to make an app that runs off the fumes from a urine sample, why are you choosing a Mega32 model that will consume much more power than more modern alternatives, and will have fewer power-saving features as well?

 

 

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.