Energy-Efficient 6T SRAM Cell Design for AI Applications

This project presents an energy-efficient 6T SRAM cell design at the 130nm node, optimized for AI applications through enhanced stability and reduced power dissipation. It supports sustainable computing in AI-driven tasks like GPU caching and edge processing.

A Glance at the Energy-Efficient 6T SRAM Cell Design

The energy-efficient 6T SRAM cell design presented in this project focuses on achieving stability and low power consumption, essential for reliable operation in AI-driven applications. This design addresses challenges like process variability and power dissipation, making it suitable for integrating systems that demand sustainable performance, like GPU caches, edge AI accelerators, and inference engines. The project explores the principle of generation, implementation, issues, improvements, and future scope of this optimized SRAM design.

For more detailed information, please refer to the full project documentation:
Project Paper

Block diagram of 6T SRAM CELL

Circuit diagram of 6T SRAM CELL

6T SRAM Performance Parameters

Parameter	Description	Min	Type	Max	Unit	Condition
Technology	130 nm CMOS Process
RL	Load resistance at output terminal	100			MΩ	VDD = 3.3V, T = 27°C
CL	Load capacitance at output terminal			50	pF	VDD = 2.7V - 3.6V, T = -40°C - 125°C, RL = 100MΩ
Vdd	Supply voltage	3.2	3.3	3.6	V	T = -40°C to 125°C
Vout	Output reference voltage (V)	1.0	1.2	1.4	V	VDD = 3.3V, T = 27°C
Tc_vout	Temperature coefficient of output voltage		20		ppm/°C	T = -40°C to 125°C, VDD = 3.3V
Vc_vout	Voltage coefficient of output voltage		5		%/V	VDD = 2.7V to 3.6V, T = 27°C
Tstart	Start-up time		3.0		μs	VDD = 3.3V, T = 27°C, RL = 100MΩ, CL = 50pF
IDD (EN=1)	Supply current when enabled	20		30	μA	VDD = 3.3V, T = 27°C
IDD (EN=0)	Supply current when disabled	0.1		1	μA	VDD = 3.3V, T = 27°C

Tools Used and Steps to Reproduce All Waveforms(Tools allowed are xschem/eSim/ngspice)

This project utilizes eSim and Ngspice for circuit simulation and waveform analysis. Below are the installation instructions and steps to run simulations on both Ubuntu and Windows OS.

Tool Installation

eSim Installation on Ubuntu

1. Download eSim Installer: Download the latest eSim installer from eSim Downloads and save it to a local directory.

2. Unpack the Installer:

   • Open the terminal, navigate to the download directory, and use the following command to unpack the installer:

     unzip eSim-2.4.zip

3. Install eSim and Dependencies:

   • After unpacking, run the following commands in the terminal to install eSim:

     cd eSim-2.4
     chmod +x install-eSim.sh
     ./install-eSim.sh --install

4. Launch eSim:

   • To start eSim, type in the terminal:

     esim

   • Alternatively, you can double-click the eSim icon created on your Desktop.

Ngspice Installation on Ubuntu

1. Open your terminal and enter the following command to install Ngspice:

   sudo apt-get install -y ngspice

eSim Installation on Windows

1. Download eSim Installer: Download eSim-2.4 installer.exe from eSim Downloads.
2. Disable Antivirus: Disable any active antivirus temporarily to avoid interference during installation.
3. Adjust Path for MinGW or MSYS:
   • If MinGW or MSYS is already installed, remove them from the PATH environment variable to prevent conflicts with eSim.
4. Run the Installer:
   • Double-click the .exe file to start the installation. Click Yes if prompted by a permission window to proceed.
5. Default Installation Path:
   • eSim will install by default in the C drive under a folder named FOSSEE. Ensure the installation path does not contain spaces or reside in "Program Files".
6. Launch eSim:
   • An eSim icon will be created on the Desktop upon installation. Double-click the icon to start eSim.

Running the Simulation

To run simulations on your netlist file (6TSRAM.cir), follow these steps:

1. Enter the Ngspice Shell:

   • Open the terminal and type:

     ngspice

2. Load and Simulate the Netlist:

   • To simulate the 6TSRAM.cir file, type:

     ngspice 1 -> source 6TSRAM.cir

3. Exit Ngspice Shell:

   • To exit the Ngspice shell, use either of the following commands:

     ngspice 1 -> exit

   • or

     ngspice 1 -> quit

Following these steps will allow you to load and simulate the netlist file in Ngspice.

Pre-Layout Simulation

To perform the pre-layout simulation of the 6T SRAM, follow these steps:

1. Clone the Repository and Set Up Files:

   • Make sure Git is installed. Open the terminal and type:

     sudo apt install -y git

   • Clone the repository:

     git clone https://github.com/Preethigrace-7/6TSRAM

Contributors

• Preethi Grace Manthena

Acknowledgments

• Kunal Ghosh, Director, VSD Corp. Pvt. Ltd. — for Hackathon opportunity
• Sumanto Kar, Assistant Project Manager, IIT Bombay — for Open Source Tools support

Contact Information

• Preethi Grace Manthena — preethigracemanthena@gmail.com
• Kunal Ghosh, Director, VSD Corp. Pvt. Ltd. — kunalghosh@gmail.com
• Sumanto Kar, Assistant Project Manager, IIT Bombay