VSD Intern - 10-bit DAC design using eSim and Sky130
What you'll learn
- eSim tool usage and installation
- DAC IP design - hierarchical approach
- Basic circuit design using eSim and Sky130
- VSD - Circuit design and SPICE simulations
- VSD - Custom layout
Most of the signals around us, in the world we live in are not digital in nature, rather they are analog. The digital systems can understand only digital signals, not analog. Hence, it becomes important to interface the digital systems we the external analog world. The analog input signals are to be converted to digital signals using Analog to Digital Converters at the input end of the digital system. After the processing by the system, the digital signals are to be converted back into analog signals using Digital to Analog Converters.
A n-bit Digital to Analog Converter (DAC) takes a n-bit digital word and converts it into a proportional analog voltage with respect to the reference voltage. The potentiometric DAC uses the concept of Voltage Divider. In an N-bit DAC, the analog voltage range, i.e. the Vref (here 3.3 V) is equally divided into 2^N voltage values. This is achieved by a series on 2^N equal resistors and taps are provided across each R. The combination of switches to tap the values is designed using the N-bit digital word as input.
This circuit was designed using eSim
eSim (previously known as Oscad / FreeEDA) is a free/libre and opensource EDA tool for circuit design, simulation, analysis and PCB design. It is an integrated tool built using free/libre and opensource software such as KiCad, Ngspice and GHDL. eSim is released under GPL.
eSim offers similar capabilities and ease of use as any equivalent proprietary software for schematic creation, simulation and PCB design, without having to pay a huge amount of money to procure licenses. Hence it can be an affordable alternative to educational institutions and SMEs. It can serve as an alternative to commercially available/licensed software tools like OrCAD, Xpedition and HSPICE.
Who this course is for:
- Beginner VLSI students curious to know about eSim and circuit design
- Expert VLSI Physical designers curious to know about custom IP design using real foundry PDKs like Sky130
Tips on order in which you need to learn VLSI and become a CHAMPION:
If I would had been you, I would had started with Physical Design and Physical design webinar course where I understand the entire flow first, then would have moved to CTS-1 and CTS-2 to look into details of how the clock is been built.
Then, as you all know how crosstalk impacts functioning at lower nodes, I would gone for Signal Integrity course to understand impacts of scaling and fix them. Once I do that, I would want to know how to analyze performance of my design and I would have gone for STA-1, STA-2 and Timing ECO webinar courses, respectively
Once you STA, there’s an internal curiosity which rises, and wants us to understand, what goes inside timing analysis at transistor level. To full-fill that, I would had taken Circuit design and SPICE simulations Part 1 and Part 2 courses.
And finally, to understand pre-placed cells, IP’s and STA in even more detail, I would have taken custom layout course and Library Characterization course
All of above needs to be implemented using a CAD tool and needs to be done faster, for which I would have written TCL or perl scripts. So for that, I would start to learn TCL-Part1 and TCL-Part2 courses, at very beginning or in middle
Finally, if I want to learn RTL and synthesis, from specifications to layout, RISC-V ISA course will teach the best way to define specs for a complex system like microprocessor
Connect with me for more guidance !!
Hope you enjoy the session best of luck for future
Kunal Ghosh is the Director and co-founder of VLSI System Design (VSD) Corp. Pvt. Ltd. Prior to launching VSD in 2017, Kunal held several technical leadership positions at Qualcomm's Test-chip business unit. He joined Qualcomm in 2010. He led the Physical design and STA flow development of 28nm, 16nm test-chips. At 2013, he joined Cadence as Lead Sales Application engineer for Tempus STA tool. Kunal holds a Masters degree in Electrical Engineering from Indian Institute of Technology (IIT), Bombay, India and specialized in VLSI Design & Nanotechnology.
Hands on with Technology @
1) MSM (mobile station mode chips) - MSM chips are used for CDMA modulation/demodulation. It consists of DSP’s and microprocessors for running applications such as web-browsing, video conferencing, multimedia services, etc.
2) Memory test chips - Memory test chips are used to validate functionality of 28nm custom/compiler memory as well as characterize their timing, power and yield.
3) DDR-PHY test chips - DDR-PHY test chips are basically tested for high speed data transfer
4) Timing and physical design Flow development for 130nm MOSFET technology node till 16nm FinFET technology node.
5) “IR aware STA” and “Low power STA”
6) Analyzed STA engine behavior for design size up to 850 million instance count ACADEMIC
1) Research Assistant to Prof. Richard Pinto and Prof. Anil Kottantharayil on “Sub-100nm optimization using Electron Beam Lithography”, which intended to optimize RAITH-150TWO Electron Beam Lithography tool and the process conditions to attain minimum resolution, use the mix-and-match capabilities of the tool for sub-100nm MOSFET fabrication and generate mask plates for feature sizes above 500nm.
2) Research Assistant to with Prof. Madhav Desai, to characterize RTL, generated from C-to-RTL AHIR compiler, in terms of power, performance and area. This was done by passing RTL, generated from AHIR compiler, through standard ASIC tool chain like synthesis and place & route. The resulting netlist out of PNR was characterized using standard software
1) “A C-to-RTL Flow as an Energy Efficient Alternative to Embedded Processors in Digital Systems” submitted in the conference “13th Euromicro Conference on Digital System Design, Architectures, Methods and Tools, DSD 2010, 1-3 September 2010, Lille, France”
2) Concurrent + Distributed MMMC STA for 'N' views
3) Signoff Timing and Leakage Optimization On 18M Instance Count Design With 8000 Clocks and Replicated Modules Using Master Clone Methodology With EDI Cockpit
4) Placement-aware ECO Methodology - No Slacking on Slack
I am a final year student of B.Tech in Electronics and Communication Engineering from National Institute of Technology Karnataka. I have a good understanding of CMOS technology, Digital electronics, RTL design and Physical design. I have worked on digital and mixed signal design projects. I have experience of working on 180nm and sky130nm technology.