Spreadtrum is based in Shanghai. Tsinghua is a state-owned corporation funded by China's Tsinghua University.
Tsinghua will pay $31 per American depositary share, a 17 percent premium to Spreadtrum's Thursday closing price of $26.45.
The offer is higher than the preliminary bid of $28.50 per ADS that Spreadtrum said it received from Tsinghua last month.
The companies put the deal's value at about $1.78 billion.
Spreadtrum currently has about 48.5 million outstanding shares, according to FactSet.
The buyout still needs approval from Spreadtrum's shareholders, as well as antitrust and other regulatory approvals. The company's board unanimously approved the deal.