# flipflop_design

**Repository Path**: wolver/flipflop_design

## Basic Information

- **Project Name**: flipflop_design
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2025-04-26
- **Last Updated**: 2025-04-26

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# flipflop_design
This project has files needed to design and characterise flipflop

Follow below steps to download Layout and run SPICE

git clone https://github.com/kunalg123/flipflop_design.git

magic -T min2.tech inv2.mag & --> This will open a MAGIC window with minimum sized inverter layout

With the above step, you can review the inverter, zoom in, zoom out, look into all layers and so on. To learn more about how the layout was drawn, what is tech file and what are its layers, refer to my below online "Custom Layout" course:

https://www.udemy.com/vlsi-academy-custom-layout/

To simulate the above Layout, use the below command

ngspice inv2.spice 

This command will run SPICE simulations, and will give you a ngspice terminal, like below.

ngspice 2 -> 

Type the below on ngspice terminal to see the input and output waveforms

ngspice 2 -> plot V(out) vs time V(in)

Review the waveform for rise delay and fall delay. To learn more about Circuit design and SPICE simulations, refer to my below online "Circuit design and SPICE simulations" course:

https://www.udemy.com/vlsi-academy-circuit-design/

https://www.udemy.com/vlsi-academy-circuit-design-part2/

You can now close magic window and ngspice window by typing "exit" in their respective terminals

Follow above similar steps for nand gate. Replace "inv2.mag" with "nand1.mag" and "inv2.spice" with "nand1.spice"

This time, on ngspice terminal type below commands to review the A->Y delay and B->Y delay

ngspice 2 -> plot V(out) vs time 

ngspice 2 -> plot V(a) V(b)

This will open 2 windows. Expand them and review waveforms. Refer to above online "Circuit design and SPICE simulations" courses

Now, to see how D-FF was built using both inv2 and nand1, repeat all above steps by replacing "nand1.mag" with "dff.mag" and "nand1.spice" to "dff.spice" 

On ngspice terminal, type below 2 commands

ngspice 2 -> plot V(q) V(clk)

ngspice 2 -> plot V(din)

This will plot output 'q' with respect to 'clk'. You will observe, except at clock edge at 6.3ns and 16.3ns, at all other rising clock edge, it violates setup time

To know more of flip-flop timing characterization, refer to my below online course on "Library Characterization and Modelling"

https://www.udemy.com/vlsi-academy-library-characterization-part-1/

All the best

Happy designing and learning...