Chipmaker Cirrus Logic (CRUS), whose biggest customer by far is Apple (AAPL), is trading near recent highs. The stock has soared 80% so far this year, outpacing the meager 2% rise in the Philadelphia semiconductor index. Shares are not at an optimal buy area, so it's best to wait for a proper chart setup. The Austin, Texas-based company makes digital audio chips for mobile devices. It gets about two-thirds of its revenue from Apple (AAPL), whose