British chipmaker Wolfson Microelectronics plc posted a wider operating loss due to weak customer demand, and forecast first-quarter revenue below analyst expectations.

Wolfson, whose audio chips are used in Samsung smartphones and Amazon's Kindle ebook reader, fourth-quarter operating loss was $7.2 million, compared with $1 million, a year ago.

Revenue fell 20 percent to $36.9 million.

The Edinburgh-based company expects first-quarter revenue to be $26-$32 million, below estimates of $33 million, according to Thomson Reuters I/B/E/S.

Wolfson has been hit by slower-than-expected product launches at its customers, derailing its long-term recovery plan after being ousted from Apple Inc products in recent years.

The company expects new launches and customers to contribute to incremental revenue in 2012.

For 2012, Wolfson said it was comfortable with the current market consensus.

(Reporting by A. Ananthalakshmi in Bangalore; Editing by Anthony Kurian)