Vitesse Semiconductor ( VTSS) shares dropped nearly 9% Monday after the chipmaker estimated fourth-quarter revenue to be below its earlier projections and issued a forecast for the current quarter that falls short of Wall Street's expectation.

Vitesse expects to report revenue of $48 million for the quarter ended Sept. 30, below its July forecast of $52 million to $53 million. According to Thomson First Call, analysts projected revenue of $52.7 million.

"During the quarter we saw some softness in turns business and delays in the production ramp of our SAS products," Vitesse President and Chief Executive Lou Tomasetta said in a statement. "Additionally, we were unable to obtain all of the required material from our assembly subcontractors in time to ship by the end of the quarter as assembly lead times have lengthened significantly."

For the fiscal first quarter ending in December, Vitesse sees revenue of $53 million to $54 million. Analysts' average estimate had called for revenue of $55.7 million, according to First Call.

Vitesse shares recently traded at $1.71, down 16 cents, or 8.6%.