DDRII Memory Packages Electrical Performance Comparison of COSBGA, TFBGA, and Standard TSOPII

The memory storage technology revolution has taken the consumer electronics by a storm in just two years. The volatile memory Dynamic Random Access Memory (DRAM) for PC and notebook computing and gaming are increasing in density and speed. With all these improvement, the memory device packaging technology is also evolving rapidly, from the leadframe packages to BGA packages [2]. Under high frequency operation, the parasitics associated with package will significantly degrade the package performance. The DRAM packages are used primarily in the fabrication of DIMM modules that are inserted to the motherboards in PC and notebook computers. With newer DRAM technology in double date rate (DDR) and its second generation, DDR2, to be deployed just two years, it has higher clock rate and I/O number. Packages therefore are changing form the leadframe TSOP type 2 to faster CSPs such as fine pitch BGA (FBGA) and chip on substrate BGA (COSBGA). This paper is focused the COSBGA package [3,4]. In this paper, the packages electrical model have been established and performs signal integrity (SI) simulation. The COSBGA has smallest parasitics when comparison with other two packages. This paper also compares the performance of the COSBGA, TFBGA and TSOPII from crosstalk noise, time skew, insertion loss and return loss for IC designer reference.