Synchronous semiconductor memory device exhibiting an operation synchronous with an externally inputted clock signal

• US 6,055,209 A
• Filed: 06/29/1998
• Issued: 04/25/2000
• Est. Priority Date: 06/27/1997
• Status: Expired due to Term

• Current Assignee: NEC Electronics Corporation (Renesas Electronics Corporation)
• Original Assignee: NEC Corporation
• Inventors: Abo, Hisashi
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): LE, THONG QUOC
• Application Number:
  US09/106,101
• Time in Patent Office: 666 Days
• Field of Search: 365/233, 365/230.06, 365/191, 365/189.07, 365/192, 365/201
• US Class Current: 365/233.12
• CPC Class Codes: G11C 7/22 Read-write [R-W] timing or clocking circuits; Read-write [R-W] control signal generators or management

Abstract

A synchronous semiconductor memory device has a pseudo internal command signal generator for generating a pseudo internal command signal which controls, in non-synchronizing with an externally inputted clock signal, an internal command signal having been generated in synchronizing with the externally inputted clock signal.

Claims

1. A synchronous semiconductor memory device comprising:

a command decoder;

a row address control circuit provided with command signal inputs from said command decoder;

a pseudo internal command signal generator for generating a pseudo internal command signal which controls, in non-synchronism with an externally inputted clock signal, an internal command signal having been generated in synchronism with the externally inputted clock signal, said internal command signal being provided as a direct input to said row address control circuit,

wherein said pseudo internal command signal generator comprises a test mode signal connector and a tester circuit for generating the pseudo internal command signal in accordance with the internal control signal.

2. The synchronous semiconductor memory device as claimed in claim 1, wherein said pseudo internal command signal generator comprises a non-bonding pad and the pseudo internal command signal is generated by an input signal into said non-bonding pad.

3. The synchronous semiconductor memory device as claimed in claim 1, wherein the pseudo internal command signal is generated in synchronizing with an asynchronous signal externally inputted.

4. A synchronous semiconductor memory device provided with a pseudo internal command signal generator for generating a pseudo internal command signal which controls, in non-synchronism with an externally inputted clock signal, an internal command signal having been generated in synchronism with an externally inputted clock signal, said internal command signal being provided as an input to a row address control signal generator to reset an output signal of said row address control signal,

wherein the pseudo internal command signal is generated by a circuit having a test mode signal input into an internal control signal in non-synchronism with the clock signal without being input into a command decoder for receiving a normal input signal and outputting a synchronous signal with the clock signal.

5. The synchronous semiconductor memory device as claimed in claim 4, wherein the pseudo internal command signal is generated upon a signal inputted into non-bonding pads.

6. The synchronous semiconductor memory device as claimed in claim 4, wherein in accordance with the internal control signal generated by an input of a command, there is provided a circuit for generating an internal command signal of another command.

7. A synchronous semiconductor memory comprising:

a command decoder with outputs providing first and second internal command signals;

a row address control circuit with first, second, and third inputs accepting the first and second internal command signals and a third internal command signal respectively;

a pseudo internal command signal generator for generating a pseudo internal command signal serving as the third internal command signal, the third internal command signal controlling said row address control circuit non-synchronously with an externally inputted clock signal, the third internal command signal having been generated in synchronism with the externally inputted clock signal,

wherein said pseudo internal command signal generator comprises a first input signal terminal feeding a first invertor, and an output of said first invertor serving as the third internal command signal,

said pseudo internal command signal generator further comprises a second input terminal feeding said first invertor via a NAND gate and a delay circuit, and

said pseudo internal command signal generator further comprises a third input terminal feeding said first invertor via said NAND gate.

8. The synchronous semiconductor memory of claim 9, wherein said pseudo internal command signal generator further comprises a second invertor in series with said first invertor;

and said first input signal terminal comprises a non-bonded input pad adapted to accept an input signal.

9. The synchronous semiconductor memory of claim 7, wherein said second input terminal is adapted to accept a write control signal.

10. The synchronous semiconductor memory of claim 9, wherein said third input terminal is adapted to accept a write control signal, said second input terminal is adapted to accept a row address strobe, and said delay circuit comprises a second invertor.