UPDATE 1-Chipmaker RF Micro forecasts 1st-qtr revenue above estimates

(Adds details, estimates, shares)

April 29 (Reuters) - RF Micro Devices Inc, a maker of chips that connect mobile devices to networks, forecast quarterly revenue above analysts' estimates due to higher demand from smartphone makers.

Shares of RF Micro, whose customers include Apple Inc and Samsung Electronics Co, rose 6 percent in extended trading after it also posted better-than-expected adjusted profit for the fourth quarter.

Increasing demand for internet connectivity and social media while on the move is driving sales of mobile devices, which use more radio frequency chips than basic phones.

Smartphone users globally are expected to triple to 5.6 billion by 2019 from 2013, according to a report by network equipment maker Ericsson. (http://r.reuters.com/byd27v)

RF Micro said in February that it would buy rival Triquint Semiconductor Inc for about $1.6 billion to boost its offering in both phone and wireless network markets. The deal is expected to close in the second half.

RF Micro, whose radio frequency chips are also used in notebooks and tablets as well as radar equipment, forecast adjusted earnings of about 17 cents per share and revenue of $305 million for the first quarter ending June.

Analysts on average were expecting earnings of 11 cents per share on revenue of $277 million, according to Thomson Reuters I/B/E/S.

RF Micro's net loss narrowed to $1 million, or break even per share, in the fourth quarter ended March 29 from $16 million, or 6 cents per share, a year earlier.

The company, which counts Samsung as its biggest customer, earned 12 cents per share, excluding items.

Revenue fell 8.8 percent to $256 million.

Analysts on average had expected a profit of 9 cents per share on revenue of $255.5 million.

Greensboro, North Carolina-based RF Micro's shares closed at $8.09 on the Nasdaq on Tuesday.

(Reporting by Aurindom Mukherjee and Supantha Mukherjee in Bangalore; Editing by Kirti Pandey)