- An Integrated Circuit is a device with a large number of electronic circuits built into a plate of Semiconductor material, usually silicon.
- An SoC is an IC with all components of a complete electronic system built into a single silicon plate (multiple ICs integrated together).
- It can be built up to several billion transistors in an area of the size of a fingerprint.
- Categories: Divided into Digital and Analog ICs, operating at a different voltage level.
- Data will be converted to numbers and to binary numbers and processed as binary.
- Switches are the basic building blocks of any digital circuit.
- Sequential - with memory
- Combinational - without memory
- Building Blocks:
- Logic Gates
- Flip Flops - the memory cells
- Logic Gates: AND, OR, NOT, XOR, NAND, NOR, XNOR
- Flip Flops - Built with logic gates.
- All logic gates can be represented using transistors.
|FIG: NAND and NOR gates representation by using CMOS transistors.|
- Gates and Flops are formed by transistors, only transistors.
- CMOS transistors (PMOS and NMOS)
- Any digital IC consists of a large number of Gates and Flip Flops (millions or billions of transistors).
Hardware Description Language (HDL)
- Digital IC in the 1960s to 2020 - a few hundreds of transistors to billions.
- HDL describes the fabrication mask in the semiconductor ICs.
- Verilog and VHDL.
- Developed by a company called Gateway design in 1984 acquired by Cadence Design Systems.
- Verilog = Verification Logic
- IEEE 1364 Standard in 1995
- Maintained by NPO called Accellera.
- An extension of Verilog developed as a new standard.
- IEEE standard (1800-2005) in 2005.
- Compared to Verilog, SV added a lot of features to enhance verification capabilities and support functional verification of the IC.
- Supports Object Oriented Programming (OOPs) for verification.
- Design perspective, both Verilog and SystemVerilog are the same except for some enhanced design features in SV - Most preferred HDL in the industry.
- SV is used for testbench creation and verification purposes mostly.
IC Design and Manufacturing Process
|FIG: IC Design Process (Source: SystemverilogAcademy)|
IC Design Process: Front-end
- The first step is to describe the functionality of an IC and its microarchitecture is defined.
- Front End: Digital/RTL Design & Verification
- Unit level
- Block/Cluster level
- System-level/SOC level
IC Design Process: Back-end
- Once the verified RTL is ready, the code will be converted to digital circuits with only flip-flops and logic gates. This process is called synthesis, and it is done by using EDA tools.
- The output of the synthesis will consist of list of logic gates connected appropriately to perform the design functionality of the IC, called a netlist - can be assumed as the circuit diagram of the final IC with only logic gates in it.
- This gate-level representation of the circuit is converted into a geometric representation of shapes which when manufactured in the corresponding layers of materials will ensure a circuit of transistors doing the intended functionality, called physical design (to generate photomask).
- Physical Design & Verification:
- Ready to go to plants (Tape out)
- Physical Design Process: