Implementing RC and coupling delay correction for SRAM
A method and circuit for implementing delay correction in static random access memory (SRAM), and a design structure on which the subject circuit resides are provided. The SRAM circuit includes a precharge enable signal coupled between precharge near and precharge far signals and wordline near and wordline far signals of the SRAM. A precharge pull down device is coupled between the precharge far signal and ground and is controlled responsive to the precharge enable signal to decrease a time delay of the falling transition of the precharge far signal. A respective word line pull up device is coupled between a respective wordline far signal and a voltage supply rail and is controlled responsive to the precharge enable signal to increase wordline voltage level upon a rising transition of the wordline far signal.
1. A circuit for implementing delay improvement in static random access memory (SRAM) including a precharge signal and respective wordline signals extending from a source near end to a distal far end of the SRAM, said circuit comprising:
a precharge enable signal; said precharge enable signal coupled between precharge near and precharge far signals and wordline near and wordline far signals at proximal and distal ends of the SRAM;
a precharge pull down device coupled between said precharge far signal and ground; said precharge pull down device being controlled responsive to said precharge enable signal to decrease a time delay of a falling transition of said precharge far signal; and
a respective word line pull up device coupled between a respective wordline far signal and a voltage supply rail; said respective word line pull up device being controlled responsive to said precharge enable signal to increase wordline voltage level upon a rising transition of said respective wordline far signal.
2. The circuit as recited in claim 1 wherein said precharge enable signal is logically equivalent to said precharge near signal and said precharge far signal.
3. The circuit as recited in claim 1 wherein said precharge pull down device is implemented with an N-channel field effect transistor (NFET).
4. The circuit as recited in claim 3 wherein said precharge enable signal is inverted and applied to a gate input of said precharge pull down NFET.
5. The circuit as recited in claim 1 wherein said respective wordline pull up device is implemented with a P-channel field effect transistor (PFET).
6. The circuit as recited in claim 1 wherein said respective wordline pull-up PFET is driven by a respective NAND gate, each said respective NAND gate having an input coupled to said respective wordline far signal and said precharge enable signal.
7. A design structure embodied in a machine readable medium used in a design process, the design structure comprising:
a circuit tangibly embodied in the machine readable medium used in the design process, said circuit for implementing delay improvement in static random access memory (SRAM) including a precharge signal and respective wordline signals extending from a source near end to a distal far end of the SRAM, said circuit comprising:
a precharge enable signal; said precharge enable signal coupled between precharge near and precharge far signals and wordline near and wordline far signals at proximal and distal ends of the SRAM;
a precharge pull down device coupled between said precharge far signal and ground; said precharge pull down device being controlled responsive to said precharge enable signal to decrease a time delay of a falling transition of said precharge far signal; and
a respective word line pull up device coupled between a respective wordline far signal and a voltage supply rail; said respective word line pull up device being controlled responsive to the precharge enable signal to increase wordline voltage level upon a rising transition of said respective wordline far signal, wherein the design structure, when read and used in the manufacture of a semiconductor chip produces a chip comprising said circuit.
8. The design structure of claim 7 , wherein the design structure comprises a netlist, which describes said circuit.
9. The design structure of claim 7 , wherein the design structure resides on storage medium as a data format used for the exchange of layout data of integrated circuits.
10. The design structure of claim 7 , wherein the design structure includes at least one of test data files, characterization data, verification data, or design specifications.
11. The design structure of claim 7 , wherein said precharge pull down device is implemented with an N-channel field effect transistor (NFET).
12. The design structure of claim 7 , wherein said precharge enable signal is inverted and applied to a gate input of the precharge pull down NFET.
13. The design structure of claim 7 , wherein said respective wordline pull up device is implemented with a P-channel field effect transistor (PFET).
14. The design structure of claim 13 , wherein said respective wordline pull up PFET is driven by a respective NAND gate, each said respective NAND gate having an input coupled to said respective wordline far signal and the precharge far signal.
15. A method for implementing delay improvement in static random access memory (SRAM) including a precharge signal and respective wordline signals extending from a source near end to a distal far end of the SRAM, said method comprising:
providing a precharge enable signal; coupling said precharge enable signal between precharge near and precharge far signals and wordline near and wordline far signals at proximal and distal ends of the SRAM;
providing a precharge pull down device coupled between the precharge far signal and ground; and controlling said precharge pull down device responsive to said precharge enable signal to decrease a time delay of a falling transition of said precharge far signal; and
providing a respective word line pull up device coupled between a respective wordline far signal and a voltage supply rail; and controlling said respective word line pull up device responsive to said precharge enable signal to increase wordline voltage level upon a rising transition of said respective wordline far signal.
16. The method as recited in claim 15 wherein providing said precharge pull down device coupled between the precharge far signal and ground includes providing an N-channel field effect transistor (NFET) coupled between said precharge far signal and ground.
17. The method as recited in claim 16 wherein controlling said precharge pull down device responsive to the precharge enable signal to decrease a time delay of a falling transition of said precharge far signal include inverting said precharge enable signal and applying the inverted precharge enable signal to a gate input of said precharge pull down NFET.
18. The method as recited in claim 15 wherein providing said respective word line pull up device coupled between said respective wordline far signal and said voltage supply rail includes providing a respective word line pull up P-channel field effect transistor (PFET) coupled between said respective wordline far signal and said voltage supply rail.
19. The method as recited in claim 18 includes providing a respective NAND gate for driving said respective wordline pull up PFET, each said respective NAND gate having an input coupled to said respective wordline far signal and said precharge far signal.
20. The method as recited in claim 15 wherein coupling said precharge enable signal between precharge near and precharge far signals and wordline near and wordline far signals of the SRAM includes directly connecting said precharge enable signal between a precharge near circuit and a precharge far circuit.