Silicon Labs ( SLAB) sank 10% Wednesday after the chipmaker offered a soft first-quarter revenue outlook.The Austin, Texas, company made $5.2 million, or 9 cents a share, for the quarter ended Dec. 30, down from the year-ago $15.3 million, or 27 cents a share. Excluding certain items, latest-quarter earnings were 24 cents a share. Revenue rose to $111 million from $110 million a year earlier. Analysts were looking for an 18-cent profit on sales of $110.6 million. "We achieved year-over-year revenue growth while managing through multiple product transitions in our mobile handset business and experiencing an overall industry slowdown in the second half of the year," said CEO Necip Sayiner. "We continue to create a diverse set of growth drivers within our business and execute on our new product introductions in our effort to drive double digit growth in 2007." During the fourth quarter, the company experienced strong demand for its Broadcast products, in particular FM tuners and satellite receivers. The broad-based mixed-signal business experienced a slight decline on a sequential basis due to lower modem shipments. Silicon Labs guided to first-quarter revenue of $111 million, shy of the $113 million Thomson Financial analyst consensus estimate. Shares sank $3.36 to $31.92.