* Xilinx Q1 EPS ex items 21 cts vs 19 cts Street view

* Sees revenue up 2-6 pct in fiscal Q2 from Q1

* Shares down more than 5 percent

SAN FRANCISCO, July 15 (Reuters) - Specialized chip maker Xilinx Inc (XLNX.O: Quote, Profile, Research) forecast second-quarter margins at the lower end of expectations, helping send its shares lower despite slightly beating first-quarter earnings estimates.

Its shares slid 5.1 percent in after-hours trade, but that came after a 4 percent rally in the regular session when stellar earnings from Intel Corp (INTC.O: Quote, Profile, Research) boosted sentiment for the chip sector in general.

Xilinx made a net profit of $38.01 million, or 14 cents per share, in the fiscal first quarter ended in June, compared with $89.3 million, or 30 cents a share, a year ago.

Excluding certain items, Xilinx earned 21 cents a share. That exceeded expectations for 19 cents a share, according to Reuters Estimates.

Xilinx said it sees sales up 2 percent to 6 percent sequentially in the fiscal second quarter, and gross margins at 61 percent.

Xilinx had said on July 2 that supply restraints made it impossible to meet demand for its cutting edge Virtex-5 devices, lowering revenues. It said that problem should be resolved in the current quarter.