Printed circuit board, memory module and memory system including the same

A memory module comprising:

• a first insulating layer;
• a first resistive pad and a second resistive pad disposed on the first insulating layer;
• a resistance disposed between and connected to the first resistive pad and the second resistive pad;
• a tab disposed on the first insulating layer and configured to transmit a signal to the first resistive pad;
• a signal line disposed on the first insulating layer and connected to the second resistive pad;
• a semiconductor package mounted on the signal line;
• a first reference layer on which the first insulating layer is disposed, the first reference layer comprising a first dielectric passage disposed under the first resistive pad, the second resistive pad and the resistance and disposed to form a return path of the signal, and a first conductive line disposed in the first dielectric passage and disposed to form a transmission path of the signal;
• a second insulating layer on which the first reference layer is disposed;
• and
• a second reference layer on which the second insulating layer is disposed, the second reference layer further forming the return path,
• wherein a capacitance of the first resistive pad and the second resistive pad corresponds to a distance between the first resistive pad and the second resistive pad and the second reference layer.

A memory system comprising:

• a main board;
• a central processing unit (CPU) connected to the main board;
• and
• a memory module mounted on the main board,
• wherein the memory module comprises:
• a first insulating layer;
• a first resistive pad and a second resistive pad disposed on the first insulating layer;
• a resistance disposed between and connected to the first resistive pad and the second resistive pad;
• a tab disposed on the first insulating layer and configured to transmit a signal to the first resistive pad;
• a signal line disposed on the first insulating layer and connected to the second resistive pad;
• a semiconductor package mounted on the signal line;
• a first reference layer on which the first insulating layer is disposed, the first reference layer comprising a dielectric passage disposed under the first resistive pad, the second resistive pad and the resistance and disposed to form a return path of the signal, and a conductive line disposed in the dielectric passage and disposed to form a transmission path of the signal;
• a second insulating layer on which the first reference layer is disposed;
• and
• a second reference layer on which the second insulating layer is disposed, the second reference layer further forming the return path,
• wherein a capacitance of the first resistive pad and the second resistive pad corresponds to a distance between the first resistive pad and the second resistive pad and the second reference layer.