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Lorenzo
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| 16F or 16LF ? |
 Posted: Tue Apr 13, 2004 2:42 am |
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May I use a PIC16F648A with a 3V�3% power supply (this PIC works
with a 3.0V<VDD<5.5V), or it's necessary a 16LF648A ?
Best regards.
Lorenzo |
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Haplo
Joined: 06 Sep 2003
Posts: 659
Location: Sydney, Australia
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Pete Smith
Joined: 17 Sep 2003
Posts: 55
Location: Chester, UK
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| Posted: Tue Apr 13, 2004 4:46 am |
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Be careful here. I've not read this data sheet, but IME, the 16F87X and the 16F84 data sheets also say they run between 2.0 and 5.5, but when you actually get down to it, only the 16LF parts will run at this voltage, but it's not obvious when looking at the documentation, unless you look at the graphs in the back.
Pete. |
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Haplo
Joined: 06 Sep 2003
Posts: 659
Location: Sydney, Australia
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| Posted: Tue Apr 13, 2004 5:23 am |
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| Yes Pete is right, my mistake. It might be a better idea to use the LF part. |
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Pete Smith
Joined: 17 Sep 2003
Posts: 55
Location: Chester, UK
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| Posted: Thu Apr 15, 2004 4:41 am |
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| Haplo wrote: | | Yes Pete is right, my mistake. It might be a better idea to use the LF part. |
This one really bit us on the arse. We made a short run of devices, which all seemed to work fine.
We then made lots more, and found about 10% of them didn't work. This being we were using F parts and were running them at 3v.
We then had to remove all the PICs, buy new ones in (LF part), and then re-program and re-attach the PICs.
Great fun!
Pete. |
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Haplo
Joined: 06 Sep 2003
Posts: 659
Location: Sydney, Australia
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| Posted: Thu Apr 15, 2004 6:48 am |
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The datasheet is mostly to blame. The only thing it mentions is that the device is a wide-range part, from 2.0v to 5.5v. And only the graphs towards the end show that for operating at very low voltages you need the LF part.
A better datasheet structure might have saved you all the fun, Pete. |
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Pete Smith
Joined: 17 Sep 2003
Posts: 55
Location: Chester, UK
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| Posted: Fri Apr 16, 2004 3:06 pm |
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| Haplo wrote: | The datasheet is mostly to blame. The only thing it mentions is that the device is a wide-range part, from 2.0v to 5.5v. And only the graphs towards the end show that for operating at very low voltages you need the LF part.
A better datasheet structure might have saved you all the fun, Pete. |
Don't I know it! 
It was my own fault for not checking the datasheet thoroughly enough.
Pete. |
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