VSD Intern – OpenRAM configuration for 4kB SRAM using Sky130

How to configure ope-source compiler OpenRAM for 130nm technology node

Overview

This webinar aims at design of 1024×32 SRAM cell array (32Kbits or 4KB) with a configuration of 1.8 V operating voltage and access time less than 2.5ns using Google SkyWater SKY130 PDKs and OpenRAM memory compiler.

Static Random-Access Memory (SRAM) has become a standard element of any Application Specific Integrated Circuit (ASIC), System-On-Chip (SoC), or other micro-architectures. For this wide variety of applications, SRAMs are configured using parameters like the word-length, bit lines, operating voltage, access time, and most importantly the technology node. The access time of an SRAM cell is the time require for a read or write operation of SRAM.

Manually configuring the SRAM for every change in parameter seems a slightly in-efficient and tedious task. Due to this reason, the memory compiler is used on a large scale, as it facilitates easy configuration and optimization of memory. OpenRAM, an open-source memory compiler is used for characterization and generation of SRAM designs.

This webinar mentioned multiple open-source circuit schematic design, layout design, SPICE simulations tools and memory compiler. The tools used are explained in detail. All the Skywater SKY130 PDKs related files are added to the repository mentioned in webinar, which can be used without installing the complete PDKs. To install or get other details of Skywater PDKs, it can be found in Skywater official website.

Objective

Introduction
- Introduction to OpenRAM
- Reasons to use OpenRAM and SKY130 technology
Environment Setup and custom cells description
- OpenRAM environment setup
- Bit-cells and sense amplifier details
- Dummy & replica bit cells, D-flipflop and write driver details
OpenRAM technology setup
- OpenRAM directory structure
- GDS file creation
- Tech file setup
- Interconnect stack layer name and technology parameters
- DRC rules and SPICE technology setup
Steps to execute OpenRAM
- OpenRAM configuration script
- Execute and review OpenRAM output files
Challenges, issues and fixes
- Custom cells boundary box
- GDS pins and tech layers
- GDS DRC issues
Summary and Conclusion

Audience Profile

VLSI Beginner who wants to quickly learn about various custom cells like 6T-SRAM, DFF
VLSI professionals who want to know how to configure open-source memory compiler OpenRAM for custom memory IP generation