Shares of Synaptics Inc fell 11 percent on Friday, a day after the touchpad maker said sales to its core market dropped during the second quarter hurt by weaker-than-anticipated PC sales.

Santa Clara-California based Synaptics derives about 60 percent of its revenue from touchpad sales to original equipment manufacturers -- which it said fell 4 percent in the second quarter.

Synaptics' bedrock notebook market has turned stone cold, Oppenheimer analyst Yair Reiner said in a note to clients.

Synaptics is the single largest touch module supplier to PC makers and counts Apple Inc , Dell Inc and Hewlett-Packard Co as some of its customers.

Second-quarter revenue, however, beat analysts' expectations by a thin margin, helped by a 48 percent surge in its sales to mobile-phone makers, the company said.

Shares of the company were down 10 percent at $28.75 in morning trading on Nasdaq. They touched a more than seven-week low of $28.40 earlier in the session.

(Reporting by Himank Sharma in Bangalore; Editing by Maju Samuel)