CSR (LSE: CSR), or Cambridge Silicon Radio, is a company based in Cambridge, England. CSR is a fabless semiconductor manufacturer whose main product lines include connectivity, audio and location chips. It is listed on the London Stock Exchange and is a constituent of the FTSE 250 Index. It is currently the 15th largest fabless semiconductor company in the world by 2009 revenue.
The Company was founded in 1998 when it split away from Cambridge Consultants as Cambridge Silicon Radio. It was first listed on the London Stock Exchange in 2004.
In 2005 the Company acquired Clarity Technologies, a leading Clear Voice Capture (CVC) business. In 2005 CSR also acquired the 3G wireless (WCDMA/UMTS/HSDPA) technology company UbiNetics. In 2007, CSR acquired Nordnav, a Swedish based GPS software company, and CPS, a Cambridge based GPS software company producing Enhanced GPS in partnership with Motorola.
On 10 February 2009, CSR announced it was merging with SiRF, the biggest global supplier of GPS chips, in a share deal worth 136 million dollars.