UPDATE 1-Skyworks Q1 tops Street, sees Q2 above market

* Q1 adj EPS $0.45 vs est $0.44

* Q1 rev $335.1 mln vs est $334 mln

* Sees Q2 adj EPS $0.38-$0.40 vs est $0.37

* Sees Q2 rev $310-$320 mln vs est $306.5 mln

* Shares down 2 pct in extended trade

Jan 20 (Reuters) - Cellphone chipmaker Skyworks Solutions Inc SWKS.O posted better-than-expected quarterly results and forecast second-quarter above market estimates on firm demand for smartphones, tablets and a shift to 4G.

For January-March quarter Skyworks, which competes with RF Micro Devices RFMD.O, Anadigics ANAD.O and Triquint Semiconductor TQNT.O, forecast second-quarter earnings of 38-40 cents a share, excluding items, on revenue of $310-$320 million.

Analysts were looking for earnings of 37 cents a share, before items, on revenue of $306.5 million, according to Thomson Reuters I/B/E/S.

In the October-December quarter, Skyworks net income doubled to $60.9 million, or 32 cents a share, from $28 million, or 16 cents a share, a year ago. Excluding items, it earned 41 cents a share, above analysts’ view of 40 cents a share.

Revenue at the company, which counts Apple AAPL.O Nokia NOK1V.HE, and Samsung Electronics 005930.KS as its customers, rose 37 percent to $335.1 million, above analysts expectation of $334 million.

Earlier in the week, Skyworks' key customer Apple Inc AAPL.O, which contributes about more than 15 percent to its revenue, posted blockbuster results and a strong outlook on dazzling sales of the iPhone and iPad.

Shares of the Woburn, Massachusetts-based company, which have nearly doubled in the last sixth months, were trading down $0.83 at $29.20 in after-market trade. It closed at $30.03 on Thursday on Nasdaq (Reporting by Swati Chitnis in Bangalore; Editing by Prem Udayabhanu)