* Says 2nd-qtr revenue to be flat or fall up to 4 pct from 1st qtr
* First-quarter earnings $0.62/shr vs est $0.61
* First-quarter revenue $612.6 mln vs est $631.4 mln
* Shares down 9 pct in extended trading (Adds details on forecast, background, CEO comment)
July 22 (Reuters) - Chipmaker Xilinx Inc forecast disappointing revenue for the second quarter after reporting lower-than-anticipated first-quarter sales due to weak sales to telecom, aerospace and defense customers.
Xilinx, whose shares fell 9 percent in extended trading, said it expected revenue in the second quarter to stay flat or fall up to 4 percent from the preceding quarter.
This would imply second-quarter revenue within a range of $588 million to $612.6 million. Analysts on average were expecting $644.3 million, according to Thomson Reuters I/B/E/S.
"June quarter revenues were impacted by weaker-than-anticipated sales from our defense and wireless businesses," Xilinx Chief Executive Moshe Gavrielov said.
The company, which gets nearly half its revenue from telecom customers, said it expects second-quarter gross margins of about 70 percent.
Net income rose to $173.6 million, or 62 cents per share, in the first quarter ended June 28, compared with $157 million or 56 cents per share, a year earlier.
Revenue rose 6 percent to $612.6 million.
Analysts on average had expected earnings of 61 cents per share on revenue of $631.4 million, according to Thomson Reuters I/B/E/S.
Shares of the company closed at $48.15 on the Nasdaq on Tuesday.
Semiconductors made by Xilinx are sold off the shelf and can be programmed by customers to do specific tasks -- eliminating hefty expenses to develop custom chips. (Reporting By Aurindom Mukherjee in Bangalore; Editing by Don Sebastian)