Tsinghua Unigroup Ltd, an operating subsidiary of Tsinghua Holdings Co Ltd, a State-owned limited liability corporation funded by Tsinghua University in China, and RDA Microelectronics Inc, a fabless semiconductor company, jointly announced on Friday the closing of the approximately $907 million merger, or $18.50 per American depositary share, of RDA Microelectronics with an affiliate of Tsinghua Unigroup.