>I didn't find a simple table. But I have found a Silicon Labs web page that is linked to a database. You enter the part number and it displays the chip information including the start-up frequency. >Go to URL:- >http://www.silabs.com/products/clocksoscillators/Pages/Utilityintro.aspx Update: I've discovered that this database does not appear to be complete. Part number 570CAC000141G does not exist for instance. In the example above if you drop the "G" off the end and search for 570CAC000141 and it will successfully return a record for a chip 570CAC000141DG. Obviously a "DG" has different specs to a "G" (device revision and temperature range - see page 27 of the data sheet). But hopefully this should give you your start-up frequency. This may be because the database holds "Custom Chip" records only and that normal production run part numbers don't appear here. But I'm just guessing. 73, Steve.