PIC MCU question

Pavel Kolinko · Joined: 15 Mar 2005 Posts: 10

Hi!
Sorry for posting a question that is not PICC related.

I was wondering what the difference is between F and LF parts in Microchip families.
For example 16LF876A and 16F876A.
I could not find any specific information in datasheets or microchip website.

As I understand LF parts are slower and work up to 10MHz only (found somewhere in small print in one datasheet), but for some reason are more expensive on Microchip website.

Any information will be greatly appreciated.
Thanks!

Thanks!

newguy · Joined: 24 Jun 2004 Posts: 1907

The F parts run only at 5V. The LF parts can run with supply voltages as low as 2V (for some processors anyway).

treitmey · Joined: 23 Jan 2004 Posts: 1094 Location: Appleton,WI USA

I think the L would stand for low as in low voltage.

On my pic 16F877A spec the 16LF877A runs 5.5 to 2.0 Volt for 0mhz to 4mhz
and the 16F877A run 5.5 to 4V from 0 mhz to 20mhz
ps The lf can run faster tha 4mhz but it a function of VDD
FMAX = (6.0 MHz/V) (VDDAPPMIN – 2.0V) + 4 MHz

So what I am saying is you are PAYING to run at a lower Vdd voltage.
And you probably get a power savings at the lower voltage.

NeoTO · Joined: 24 Aug 2005 Posts: 9

As far as I know, LF versions run at lower voltages (from 2V on).
The only problem i had with these, that i had to turn off BODEN fuse to get them working at 3 V.

Guest · Posted: Mon Aug 29, 2005 10:22 am

Thanks for detailed reply!

treitmey, I was wondering where you got the formula for FMAX as a function of VDD.

NeoTO · Joined: 24 Aug 2005 Posts: 9

the formula is in datasheet

Guest · Posted: Mon Aug 29, 2005 10:31 am

Oops!

There is all the information about PIC16LF* right there!
I have searched for *LF*, but it didn't find the graph. Very Happy

Thanks guys!