Memory system with stable termination of a pair of differential signals transmitted via a pair of transmission lines

• US 7,456,650 B2
• Filed: 06/09/2005
• Issued: 11/25/2008
• Est. Priority Date: 06/14/2004
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Dong-yang
• Primary Examiner(s): Cho; James H.
• Assistant Examiner(s): WHITE, DYLAN C
• Application Number:
  US11/148,475
• Publication Number:
  US 20050275425A1
• Time in Patent Office: 1,265 Days
• Field of Search: 326/30, 326/86, 327/108
• US Class Current: 326/30
• CPC Class Codes: H04L 25/0272 Arrangements for coupling to multiple lines, e.g. for differential transmission
• CPC Class Codes: H04L 25/0298 Arrangement for terminating transmission lines

Abstract

Provided is a memory system in which a pair of differential signals transmitted via a pair of transmission lines are prevented from being terminated at the same voltage during a standby mode, thereby preventing a receiver from entering an unstable state. The memory system includes a pair of transmission lines, a transmitter that outputs a pair of differential signals to the pair of transmission lines, and a receiver that receives the pair of differential signals via the pair of transmission lines. A first termination voltage is applied to one of the pair of transmission lines, and a second termination voltage is applied to the other transmission line. The first termination voltage is determined to be different from the second termination voltage.

Claims

1. A system comprising:

a single-ended transmission line;

a pair of differential transmission lines;

a transmitter outputting a single-ended signal to the single-ended transmission line and a pair of differential signals to the pair of differential transmission lines;

a receiver receiving the single-ended signal via the single-ended transmission line and the pair of differential signals via the pair of differential transmission lines;

a first termination voltage applied to one of the pair of differential transmission lines;

a second termination voltage applied to the other differential transmission line; and

a third termination voltage applied to the single-ended transmission line;

a first termination resistor, one end of which is connected to one of the pair of differential transmission lines;

a second termination resistor, one end of which is connected to the other of the pair of differential transmission lines;

a third termination resistor, one end of which is connected to the single-ended transmission line,

wherein the first termination voltage is different from the second termination voltage, and the third termination voltage is half a power supply voltage applied to the transmitter, and

wherein the resistance values of the first termination resistor, the second termination resistor and the third termination resistor are substantially equivalent.

2. The system of claim 1, wherein the transmitter is a memory device, and the receiver is a memory controller.

3. The system of claim 1, wherein the transmitter is a memory controller, and the receiver is a memory device.

4. A system comprising:

a single-ended transmission line;

a pair of differential transmission lines;

a transmitter outputting a single-ended signal to the single-ended transmission line and a pair of differential signals to the pair of differential transmission lines;

a receiver receiving the single-ended signal via the single-ended transmission line and the pair of differential signals via the pair of differential transmission lines;

a first termination resistor, one end of which is connected to one of the pair of differential transmission lines;

a second termination resistor, one end of which is connected to the other differential transmission line;

a third termination resistor, one end of which is connected to the single-ended transmission line;

a fourth termination resistor, one end of which is connected to one of the pair of differential transmission lines and the other end of which is connected to the other of the pair of differential transmission lines;

a first termination voltage applied to the other end of the first termination resistor;

a second termination voltage applied to the other end of the second termination resistor; and

a third termination voltage applied to the other end of the third termination resistor,

wherein a resistance value of the first termination resistor is different from a resistance value of the second termination resistor, a resistance value of the third termination resistor is substantially equivalent to a resistance value of the fourth termination resistor, the first termination voltage is different from the second termination voltage, and the third termination voltage is half a power supply voltage applied to the transmitter.

5. The system of claim 4, the transmitter is a memory device, and the receiver is a memory controller.

6. The system of claim 4, wherein the transmitter is a memory controller, and the receiver is a memory device.