CSS555 vs CSS555C?

I am thinking of using the CSS555/CSS555C timer IC in an upcoming project where I need a low power timer. Has anyone here used these and care to share their experiences? These are timers just like the classic 555 timer IC but they are extremely low power (even lower than the newer CMOS based 555 IC's) and can be programmed with an Uno based programmer as described here: Project hub link

Which version of the two IC's do you prefer (the C or non-C version) and why? The C version has the programmable capacitor in it. Even if you don't see the need for that capacitor, do you suggest still getting the C-version to have it down the road? Or is it better to go with the non-C version for some other aspects? Any input is welcome. Thank you!

I have an application for the high speed TLC555, another application for the cheap NE555. That are the two properties I based my selection on. I’m sure there are applications for the CSS555 or CSS555C (I haven’t had the need for the ultra low power or ultra long timer periods myself).

Your exact application will tell you which is the most suitable part. Until you tell us exactly how you intend to use this part, it’s hard to comment on which one would be the most suitable for you.

Thanks! Yes, I have used both the regular NE555 and the CMOS version TLC555 in projects too. However, the CSS555 is new to me and the reason I am asking is that when I was about to order it I see they have the two versions. Thus, do I get the non-C as I had planned, get the C-version instead, or get both? At the moment I don't see a need for the C-version but if it is same in all aspects and just adds the capacitor, it might be the one to get. The price is not that much more for the C-version. Decisions, decision, decisions... :slight_smile:

Thus, do I get the non-C as I had planned, get the C-version instead, or get both?

Until you tell us exactly how you intend to use this part, it’s hard to comment on which one would be the most suitable for you.

As for intended use; yes, I am planing on using it as a monostable timer generating delays of 1-2 hours.The key parameter is low power consumption. My TLC555 CMOS 555 timer based solution uses about 120uA. Thus, with these CSS555 I hope to bring that down to 5uA or so.

However, if anyone knows of an even better IC for this purpose, please share. But the IC must support 5V operation and be in a DIP/DIL package for easy use with solderless breadboards. I have found some other watchdog timer IC's that use much less than 5uA but they are all surface mount components and I don't want that and for me 5uA is probably low enough. Thank you!

The ATtiny402 can do that kind of timing (it's got a built-in RTC) at a power budget of about 1 µA - just needs a bit of clever use of sleep modes.

No DIP8 package available but you can of course simply mount it on a SOP8 breakout board, that gives you a DIP footprint. It's how I do my prototyping and experimenting with such parts. Only external part needed is a 100nF cap, which you can of course just solder on top of the same breakout board.

A single chip one shot with extremely long time constants is better built with a CMOS counter such as CD4060.

In the linked circuit, the trigger happens to come from the turn on pulse, but you don't have to use that, you can connect your trigger to whatever input. The 4060 has an on-chip oscillator which you can set to a shorter time constant like 100ms-1000ms and then use the counter portion to extend that. When the timer overflows, it resets like a one shot.

wvmarle:
The ATtiny402 can do that kind of timing (it's got a built-in RTC) at a power budget of about 1 µA - just needs a bit of clever use of sleep modes.

Thanks! I have heard a lot of good things about this cool IC. I think I am going to try it out on a future project. Looks like fun. 1uA is excellent too.
Yes, it seems finding something in the DIP/DIL format is not easy. I know about these carriers and it might be "easy" so solder to but I am not there yet... I prefer to stick with DIP/DIL if I can for now. In surface-mount-land there are many new IC's that fit the bill it seems. Here is one example with a power draw of only 35nA (!!!):
https://www.mouser.com/new/texas-instruments/ti-tpl5111-timer/

aarg:
A single chip one shot with extremely long time constants is better built with a CMOS counter such as CD4060.
Timer with 4060 - Coolcircuit.com

Another good one! Looks interesting. I will have to look into that in more detail. Thank you!!