Building an extreme low power device and need to select an ATtiny with sleep current around or below 1uA (at 4V). Is there any difference in the sleep current for the ATtiny45 vs the ATtiny85?
Posted Aug 16, 2016, 6:21 PM UTC
The only difference between the attiny25, attiny45 and attiny85 the flash memory size (flash, sram, eeprom).
So no there is no difference.
EDIT: There is some more! Check out sleemanj's post. The info about the increased sleep current in Rev A attiny45's could be relevant in some very rare cases.
-- Edited. Thanks sleemanj!
The only difference between the attiny25, attiny45 and attiny85 the flash size
Not quite.
The 25 has a special mode which it can be placed into to flip some pins around so it is compatible with the (discontinued) ATtiny15. This is not present on the higher models.
They also have different EEPROM and RAM sizes.
The Tiny45 also has quite a bit more errata than the others in earlier revisions of the chip (including some cases where the power usage is higher in sleep mode, in Rev A 45's).
I didn't knew that the 25 has this special mode and also that the Rev A 45 had a higher power usage in some cases in sleep mode. I should be more careful using words like "only". :)
Especially the higher power usage on the ATTiny45 could be important, even though I think it's very unlikely to get one of these.
Thanks!
Thanks, that's exactly what I needed!
No prob. :) was there too.
When I had to build a low power device, I used an AtTiny13A. From what I understand, the PicoPower Atmels are the best chips to look at if you want super low current draw.
I couldn't get my multimeter to register just how low the current it had gotten in sleep mode, but safe to say the batteries that are powering the device will naturally kill themselves over time before the device ends up running them flat.
Ok, so maybe in redditland anything <1uA is "practically" the same. But in the harsh reality of extremely low power apps the ATtiny85 does draw more sleep current than the ATtiny45. Yeah, I ran the test. We are talking 0.15uA vs 0.30uA. So the '45 is preferred, if I can make the code fit.
That information is found in the electrical characteristics sections of the datasheets of the two parts.
Would you like someone to read the datasheets for you?
From the datasheet it appears there's no difference, but they're a little vague. I was just wondering if someone really knew if there's a difference.
They aren't being vague just to be annoying. If it says 2uA max there are probably conditions where it does draw 2uA, even if the one on your bench just seems to be drawing 0.5uA or whatever. In particular, in the deepest shutdown states, power consumption is dominated by leakage current, which will be highly temperature dependent.
see: http://www.atmel.com/images/doc7903.pdf