Semiconductor Memory Device having different reference voltages to memory slots

PURPOSE: A semiconductor memory device having a different reference voltage per memory slot is provided, which improves a reliability by minimizing the influence of noise generated on a Rambus channel, and reads data accurately without regard to the noise, and also increases a noise immunity. CONSTITUTION: The memory device comprises a number of reference voltage sources(85-1,85-2) in correspondence to a number of memory modules. The reference voltage sources apply reference voltages(Vref1,Vref2) of different voltage levels respectively to a corresponding memory module among the memory modules respectively. The first reference voltage source(85-1) comprises serial resistors(R81,R82) connected to a termination voltage(Vterm) and a ground, and provides the first reference voltage to the first memory module, and therefore an equal reference voltage(Vref1) is applied to Rambus DRAMs(82-1,82-2) on the first memory module. And the second reference voltage source comprises serial resistors(R83,R84) connected to the termination voltage and the ground, and provides the second reference voltage to the second memory module, and therefore an equal reference voltage(Vref2) is applied to Rambus DRAMs(83-1,83-1) on the second memory module.