Stock futures drop on revenue concerns as earnings roll in

Stock index futures fell on Tuesday on concerns the slow global economy will continue to dent corporate revenues, with a host of companies set to post quarterly results.

* According to Thomson Reuters data, 33 S&P 500 companies are scheduled to post earnings on Tuesday. Of the 123 S&P 500 companies that have reported earnings through Monday morning, 60.2 percent have topped analysts' expectations, shy of the 62 percent average since 1994 and below the 67 percent average over the past four quarters.

* After the close on Monday, Texas Instruments Inc said quarterly revenue fell as demand for its chips slipped on economic concerns, and the company forecast more weakness this quarter in all its customer segments.

* United Technologies Corp reported a 3.3 percent decline in earnings on Tuesday, as the strengthening U.S. dollar sapped the recorded value of its foreign sales.

* Fellow Dow component DuPont reported a sharp drop in quarterly profit on Tuesday, due in part to falling demand for titanium dioxide paint pigment and solar panel parts.

* Apple Inc shed 0.6 percent to $630.01 in premarket trade. The company is expected to make its biggest product move on Tuesday since the iPad's debut two years ago, launching a smaller, cheaper tablet into a market staked out by Amazon.com Inc and Google Inc .

* Whirlpool Corp reported a higher-than-expected quarterly profit, helped by price increases and tight cost controls, and the world's largest appliance maker raised its earnings outlook for the year.

* Consumer electronics chain RadioShack Corp reported a much wider-than-expected quarterly loss, hurt by weak margins in its smartphone business.

* European stocks fell broadly as third quarter results presented a mixed picture, hitting a one-week low that analysts said might encourage some investors back into the market.

(Reporting by Chuck Mikolajczak; Editing by Chizu Nomiyama)