PDA

View Full Version : PIC current specs?



droptail
- 1st February 2006, 17:24
Data sheet says PIC 16C715 can sink/source 25mA. No probs with doing this continuously on at least 1 pin?
For reference, what limitaions are there, for ex, doing on all 8 B port would be 200 mA, thats alot of heat, 1W I believe.

rhino
- 1st February 2006, 17:58
Be sure to read the "Electrical Characterists" section in the data sheet. It states 25mA per pin, but it should also say max current draw per PORT as well. Here's an excerpt from the 16F88 datasheet.
Maximum output current sunk by any I/O pin............................................... .................................................. .....25 mA
Maximum output current sourced by any I/O pin .................................................. ..............................................25 mA
Maximum current sunk by PORTA............................................. .................................................. .....................100 mA
Maximum current sourced by PORTA............................................. .................................................. ................100 mA
Maximum current sunk by PORTB............................................. .................................................. .....................100 mA
Maximum current sourced by PORTB .................................................. .................................................. ..........100 mA

droptail
- 2nd February 2006, 02:01
Yes, I see about the max Port current limits. Now about the max pin current again, <25mA continuous is reliable if other max's are adhered to? Any experience with sourcing this?

rhino
- 2nd February 2006, 02:59
Nope... can't say I've ever tested how long an output can sink or source current continuously. But then.... what does continuously really mean? Hours, days, years? I did dig through the same data sheet again, and didn't see any charts relating to this. Sounds like what you want is some endurance test data. Maybe one of the 'ol pros can give you some information based on some of their applications. Sorry I could'nt be any more help.

abbtech
- 11th February 2006, 08:11
Yes, I see about the max Port current limits. Now about the max pin current again, <25mA continuous is reliable if other max's are adhered to? Any experience with sourcing this?

My prototype LED stair lighting system direct drives LEDs at 20mA. The lights pull 160mA directly from the PIC and I have had no problems with it...

http://www.alan-parekh.com/stair_lights.html

droptail
- 11th February 2006, 17:34
What is the Imax allow port pin sink/source for the PIC you are using? Is it 20 or 25mA?

Thanks

abbtech
- 12th February 2006, 02:52
What is the Imax allow port pin sink/source for the PIC you are using? Is it 20 or 25mA?

Thanks

I am using a 16f628 it can sink or source 25mA per pin, there is a MAX of 200mA for both ports combined.

droptail
- 12th February 2006, 17:22
Good info. Post back here if you find the PIC ever getting hot or other related probs.

droptail
- 12th February 2006, 17:31
Good info. Post back here if you find the PIC ever getting hot or other related probs, and I will do the same. I am sourcing 19mA and about 50 mA total port.