Recommendation for si4734 external clock source

Question

The si4734/4735 FM receiver has two options for clock input, one is to use the typical crystal oscillator (a crystal + pair of capacitors to ground), attached to the DCLK+RCLK pins, the other is to feed a "finished" clock source to just the RCLK pin. The first is the most common design, all the examples and app notes I saw use it. But this limits you to use its analog audio outputs, since for digital audio output the DCKL pin is needed.

Has anyone tried the second option? Any recommendations for a good (small+cheap) clock source circuit?

http://www.b-kainka.de/SI4735Srds1.html

http://www.elexs.de/SI4735g.html

http://www.silabs.com/pages/DownloadDoc.aspx?FILEURL=Support%20Documents/TechnicalDocs/Si4734-35-C40.pdf

http://www.silabs.com/products/audiovideo/amfmreceivers/Pages/Si473435.aspx

Answer 1

A 32.768kHz CMOS oscillator would probably be the usual thing to use. Here is a Farnell link with a few options from £1.94 upwards (check other vendors for more options)
If you want to go cheaper then rolling your own with a crystal and inverting gate would be an option - here is an app note with some info on doing so.