Whats the fastest PIC when running at 3.3 volts ?

nurquhar · Joined: 05 Aug 2006 Posts: 149 Location: Redditch, UK

Whats the fastest PIC device when running on a 3.3 volt supply ? Preferable a flash device.

I have looked a number of 18F devices that have a maximum clock of 40Mhz. However according to the "Electrical Characteristics" in the data sheets most have to be de-rated when run below about 4v. Are there any that beat this rule ?

Regards
Neil

ckielstra · Joined: 18 Mar 2004 Posts: 3680 Location: The Netherlands

I don't think there is a PIC16 running up to 40MHz but there are many PIC18 processors that will. Go to the Microchip website and perform a parametric search for processors with 'Operation Voltage. Max = 3.6V'.

For example I checked the PIC18F87J10 family (PIC18F65J10, 65J15, 66J10, etc) these will run 40MHz even at voltages as low as 2.35V

SET · Joined: 15 Nov 2005 Posts: 161 Location: Glasgow, UK

New 'K' series can run to 64MHz:

http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1335&dDocName=en530013

nurquhar · Joined: 05 Aug 2006 Posts: 149 Location: Redditch, UK

Thanks for the info. I was sure there must be an easy way to find a 3.3v device without looking at every datasheet on uk.farnell.com

Can I use my normal ICD connection hookup (eg as per 5v 16F877) with these 3.3v devices ? I am wondering if I "supply" power to my circuit from my ICD2 or Mach X will it "blow its brains" out by sourcing 5v or will these programmers automaticaly switch down too 3.3v ?

If the ICD2 (and Mach X) can only source 5v do I have to have a 5v and 3.3v reg and connect the ICD 5v between the two as below ?

Vsup ---[5v reg]---{ICD 5v}---[3.3v reg]------- Vdd