Memory systems capable of reducing electromagnetic interference in data lines

Abstract

A memory system capable of reducing electromagnetic interference in data lines includes a memory controller and a synchronous semiconductor memory device. The memory controller controls the phases of write data strobe signals, which fetch write data transmitted through respective data lines. The synchronous semiconductor memory device receives the write data and controls the phases of read data strobe signals to be different from each other.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments will become more apparent by describing in detail the example embodiments shown in the attached drawings in which:

FIG. 1 is a block diagram of a related art memory system;

FIG. 2 is a block diagram of a memory system, according to an example embodiment;

FIG. 3 is a timing diagram illustrating an example write operation performed in the memory system of FIG. 2; and

FIG. 4 is a timing diagram illustrating an example read operation performed in the memory system of FIG. 2.

Claims

1. A memory system comprising: a memory controller configured to control phases of a first and a second write data strobe signals to be different from each other, and configured to receive read data, the first and second write data strobe signals fetching write data transmitted through data lines; anda synchronous memory device configured to receive the fetched write data, and configured to control phases of a first and a second read data strobe signal to be different from each other, the first and second read data strobe signals fetching read data transmitted through the data lines.

2. The memory system of claim 1, wherein the memory controller includes, a controller clock generator configured to synchronize an internal clock signal of the memory controller with a clock signal provided by the synchronous memory device to generate the first write data strobe signal,a write delay unit configured to delay the first write data strobe signal by a write delay time to generate the second write data strobe signal, anda data output buffer configured to buffer the write data in response to the first and second write data strobe signals and transmit the write data.

3. The memory system of claim 2, wherein the memory controller further includes, a write controller configured to control the write delay time of the write delay unit, anda data strobe output buffer configured to buffer the first and second write data strobe signals and transmit the first and second write data strobe signals to the synchronous memory device via first and second data strobe lines, respectively.

4. The memory system of claim 3, wherein the synchronous semiconductor memory device includes, a data strobe input buffer configured to buffer the first and second write data strobe signals received from the memory controller to generate first and second internal write data strobe signals, anda data input buffer configured to buffer the write data received from the memory controller in response to the first and second internal write data strobe signals to generate internal write data.

5. The memory system of claim 2, wherein the write delay time corresponds to about a quarter of a period of the clock signal.

6. The memory system of claim 2, wherein the write delay unit includes, an inverter chain.

7. The memory system of claim 2, wherein the controller clock generator includes, a phase locked loop circuit or a delay locked loop circuit.

8. The memory system of claim 1, wherein the synchronous memory device includes, a memory clock generator configured to synchronize an internal clock signal of the synchronous memory device with a clock signal from the memory controller to generate the first read data strobe signal,a read delay unit configured to delay the first read data strobe signal by a read delay time to generate the second read data strobe signal, anda data output buffer configured to buffer the read data in response to the first and second read data -strobe signals and transmit the read data to the memory controller via the data lines.

9. The memory system of claim 8, wherein the synchronous semiconductor memory device further includes, a read controller configured to control the read delay time of the read delay unit, anda data strobe output buffer configured to buffer the first and second read data strobe signals and transmit the first and second read data strobe signals to the memory controller via first and second data strobe lines, respectively.

10. The memory system of claim 9, wherein the memory controller includes, a data strobe input buffer configured to buffer the first and second read data strobe signals received via the first and second data strobe lines to generate first and second internal read data strobe signals, anda data input buffer configured to buffer the read data received via the data lines in response to the first and second internal read data strobe signals to generate internal read data.

11. The memory system of claim 8, wherein the read delay unit includes, an inverter chain.

12. The memory system of claim 8, wherein the memory clock generator includes, a phase locked loop circuit or a delay locked loop circuit.

13. The memory system of claim 8, wherein the read delay time corresponds to about a quarter of a period of the clock signal.

14. A memory system comprising: a memory controller configured to transmit write data through data lines based on a first write data strobe signal and a second write data strobe signal, the first and second write data strobe signals having different phases, and the memory controller being further configured to receive read data; anda synchronous memory device configured to receive the transmitted write data and transmit read data to the memory controller based on a first read data strobe signal and a second read data strobe signal, the first and second read data strobe signals having different phases.

15. The memory system of claim 14, wherein the memory controller includes, a controller clock generator configured to synchronize an internal clock signal of the memory controller with a clock signal provided by the synchronous memory device to generate the first write data strobe signal,a write delay unit configured to delay the first write data strobe signal by a write delay time to generate the second write data strobe signal, anda data output buffer configured to buffer the write data in response to the first and second write data strobe signals and transmit the write data.

16. The memory system of claim 15, wherein the memory controller further includes, a write controller configured to control the write delay time of the write delay unit, anda data strobe output buffer configured to buffer the first and second write data strobe signals and transmit the first and second write data strobe signals to the synchronous memory device via first and second data strobe lines, respectively.

17. The memory system of claim 16, wherein the synchronous semiconductor memory device includes, a data strobe input buffer configured to buffer the first and second write data strobe signals received from the memory controller to generate first and second internal write data strobe signals, anda data input buffer configured to buffer the write data received from the memory controller in response to the first and second internal write data strobe signals to generate internal write data.

18. The memory system of claim 14, wherein the synchronous memory device includes, a memory clock generator configured to synchronize an internal clock signal of the synchronous memory device with a clock signal from the memory controller to generate the first read data strobe signal,a read delay unit configured to delay the first read data strobe signal by a read delay time to generate the second read data strobe signal, anda data output buffer configured to buffer the read data in response to the first and second read data strobe signals and transmit the read data to the memory controller via the data lines.

19. The memory system of claim 18, wherein the synchronous semiconductor memory device further includes, a read controller configured to control the read delay time of the read delay unit, anda data strobe output buffer configured to buffer the first and second read data strobe signals and transmit the first and second read data strobe signals to the memory controller via first and second data strobe lines, respectively.

20. The memory system of claim 19, wherein the memory controller includes, a data strobe input buffer configured to buffer the first and second read data strobe signals received via the first and second data strobe lines to generate first and second internal read data strobe signals, anda data input buffer configured to buffer the read data received via the data lines in response to the first and second internal read data strobe signals to generate internal read data.