IMPLEMENTATION AND SIMULATION OF CMOS ANALOG MULTIPLIER USING SKYWATER 130NM PDK
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TOPIC : 130nm CMOS Analog Multiplier
TOOL USED : e-Sim - Open Software

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ABOUT eSim : 
eSim (previously known as Oscad / FreeEDA) is a free/libre and open source EDA tool for circuit design, 
simulation, analysis and PCB design. It is an integrated tool built using free/libre and open source 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.

source : (https://esim.fossee.in/)

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STEPS TO IMPLEMENT ANALOG MULTIPLIER :

STEP 1 : Choose a topic (My Topic : 130nm CMOS Analog Multiplier)

STEP 2 : Do Literature Survey and know about the topic from scratch. By doing so one can able to know the concept behind 
the circuit and how to implement using any tool (I used : eSim-One of the best open source software under development).
Refer Standard Books and ieee(or similar standard)papers to know the concept.

STEP 3 : Install eSim software from (https://esim.fossee.in) official website with no cost. It is available for both windows
and ubuntu platforms.

STEP 4 : Get used to eSim platform by doing simple circuit like invertor and simulate. 

STEP 5 : Now Start implementing the circuit (My circuit : 130nm CMOS Analog Multiplier). Place the necessary components 
and connect the components using wire with input and output ports.

STEP 6 : After circuit implementation "perform electrical rules check" to check any errors accurred while connecting components
and rectify it if any.

STEP 7 : Select "Generate Netlist", which generates the required netlist file for the project.

STEP 8 : Since the circuit is implemented using 130nm technology, Skywater130 pdk is used to modify the component specifications.

STEP 9 : To do that download sky130 pdk and edit the generated netlist with sky130 component specifications. 
(For example : Replace CMOSP,mos_p with sky130_fd_pr__pfet_01v8). Similarly do for corresponding components with sky130
specifications)

STEP 10 : The modified file must be placed in the same path as sky130 folder. Run the modified netlist(.cir) file using ngspice
to display the output waveform.

STEP 11 : If the output is not as expected check the circuit connections and debugg the errors any occurred while simulating.

---------------------------------------------Happy Learning--------------------------------------

--------------------------------------LEARNT A LOT FROM THIS MARATHON----------------------------

------------------------------------------------THANK YOU-----------------------------------------

