low power design...PIC...9V buzzer...voltage reg?

[valemike]

Hi,

I need to use a 9V battery to power a piezo beeper. Looks like this 9V battery then would have to provide the voltage to my nanowatt PIC.
(If i didn't have the beeper, then i'd probably just choose two AAA 1.5 batteries and not need a voltage regulator, and be done with.) I'll be in sleep mode 99.9% of the time until a switch closes, then I sound the beeper for 2 minutes and then go back to sleep.

here's my question:
Since i'm forced to use a 9V battery, I will need a way to drop the voltage down to 2V-5.5V. An 8-pin PIC can work down to 2V.

However, I will need to drop the voltage down, and unfortunately will drain current from the battery.

The only way to do this is to use a voltage regulator which operates in the microamp range, right? Anything other form of voltage regulation, such as a clamping zener will definitely use up milliamps?

[Kenny]

Yes, a micropower voltage regulator like the MAX666 would be a good way to go. Zeners consume too much current.
http://pdfserv.maxim-ic.com/en/ds/MAX663-MAX666.pdf
You can set the voltage you want, and it also has a low battery output.
I have used them in the past successfully, but perhaps there is an even better one available now.

[PCM programmer]

The Seiko Instruments S-817 series has only 1.2 ua of quiescent current.
It will work with a 9v battery. It's cheap, too. We used the 5v version
in the SOT23-5 package in one project. http://www.mouser.com
has it. Here is the manufacturer's page:
http://speed.sii.co.jp/pub/compo/ic/en/param_chrt.jsp?subcatID=22

[valemike]

Thanks for the parts suggestions guys.