Spreadtrum Communications, a Shanghai maker of wireless chips, has acquired Quorum Systems, a San Diego, Calif., CMOS RF transceiver maker, and its unclear whether Quorum’s Silicon Valley  investors were able to make a significant return.

The deal is valued at $70 million including $55 million in cash and $15 million in stock. It also includes a $6 million cash earn-out over two years, based on performance.
Quorum had raised almost $40 million in funding from firms like Band of Angels, CampVentures, Crescendo Ventures, Greylock Partners, Enterprise Partners Venture Capital, and Kleiner Perkins Caufield & Byers. Since investors usually claim only a portion of a company when they invest, the sale price can’t have given them too much of a profit, though that is speculation on our part.

Quarum’s radio chip is embedded in cellphones. It is designed so that phones work with both Wi-Fi and GPS networks.