Keeping track of the Date and Time despite power loss

Hi!

I'm considering something like this IC to keep track of date and time in my project (an automated sprinkler system):

Here is the data sheet:

http://datasheets.maxim-ic.com/en/ds/DS1339-DS1339U.pdf

Looks pretty cool with the snazzy I2C interface and I can use a small watch battery for a backup power source (the device has pins for backup power).

What I don't like about the IC is that it is surface mount which means I have to make an adapter for my project which is currently a breadboard project and I will need an oscillator. Does something like this exist in a through-hole technology form with integrated clock?

Is there a better way for me to do what I want to do here (like make a backup power setup for the Arduino or something)?

Thanks!

I happened to be browsing over at yourdunio.com before reading this, and I recalled they had a RTC in an electronic brick format:
http://arduino-direct.com/sunshop/index.php?l=product_detail&p=278.

Oh cool! I like not having to do my own PCB layout (I suck at it...need practice...can't believe how long I've been an EE without really getting a handle on it...).

Would a Chronodot be suitable?

I2C and +/- 2ppm accuracy.

Pete

After my initial posting, I wandered over to adafruit, and saw a RTC better for a breadboard environment:

The one posted by el_supremo also looks like it would work, and it appears to be more accurate than the above RTC.

Hmm... idk. They all look like super great options. I might go with the chronodot, but the price seems really high to me... at some point I have to wonder if hacking a Timex wrist watch would somehow be more practical (I know it wouldn't, I jest).

Add a crystal to this
http://www.dipmicro.com/store/DS1307N
and a coin cell battery/holder.
I've them to be pretty accurate.
DS3232 may be more accurate, but not available as a DIP
http://www.maxim-ic.com/datasheet/index.mvp/id/4051
but its 'larger' pins (relative to other SMT parts) are not too hard to solder on a breakout board.

These are very small and include a temperature sensor and NV storage:
http://emartee.com/product/42013/Tiny%20RTC%20DS1307%20Shield%20%20Arduino%20Compatible

--- bill