公开(公告)号：US20190052268A1

公开(公告)日：2019-02-14

申请号：US15922332

申请日：2018-03-15

Applicant: SAMSUNG ELECTRONICS CO., LTD.

Inventor： JUN-HA LEE ,  CHANG-KYO LEE ,  YOON-JOO EOM

IPC: H03K19/00 ,  G11C7/10

CPC classification number: H03K19/0005 ,  G11C7/1057 ,  G11C7/1084 ,  G11C11/4093 ,  G11C29/022 ,  G11C29/028

Abstract: A memory module includes an external resistor and a plurality of memory devices commonly connected to the external resistor. Each of the memory devices includes a first reception pad and a first transmission pad. The first reception pad is associated with receiving an impedance calibration command and the first transmission pad is associated with transmitting the impedance calibration command. Each of the memory devices transfers the impedance calibration command to a first memory device which is selected as a master among the plurality of memory devices through a ring topology. The first memory device performs an impedance calibration operation, determines a resistance and a target output high level voltage of an output driver in response to the impedance calibration command, and transfers the impedance calibration command to a second memory device after performing the impedance calibration operation.