PRINTED CIRCUIT BOARD FOR DOUBLE DATA RATE(DDR) REGISTERED DOUBLE IN-LINE MEMORY MODULE(DIMM)

摘要

PURPOSE: A printed circuit board for DDR registered DIMM is provided to allow two type of phase locked loops(PLLs) to be mounted at a single PCB by arranging a jumper unit to the PCB of DIMM. CONSTITUTION: A printed circuit board includes a jumper unit(10) for selectively supplying 2.5V or 3.3V to the 16th pin of the PLL. The jumper unit includes the first pad(12) connected to the voltage source of 2.5V; the second pad(14) connected to the 16th pin of the PLL; the third pin(16) connected to the voltage source of 3.3V; and the fourth pad(18) connected to the 16th pin of the PLL. When CDC857-2 type PLL is mounted, the first pad and the second pad of the jumper unit are interconnected so as to apply 2.5V to the 16th pin of the PLL. When CDC857-3 type PLL is mounted, the third and the fourth pad of the jumper unit are interconnected so as to apply 3.3V to the 16th pin of the PLL.