200 chip definitions everyone should know

Epiphany-III Wirebond

Given how important chips are to modern society EVERYONE should understand and appreciate how they are made.  Every field has its own set of terms, jargon, and acronyms (engineers love acronyms!). As you would expect, chip design is no different. If you are new to chip design, it might take you a few days to read through the Wikipedia entries for each one of these 200 topics. If you are interested in actually building chips, you will need to master all 200 of them. The sources for the table can be found HERE. (PR’s appreciated)


Andreas Olofsson is the founder of Adapteva and the creator of the Epiphany architecture and Parallella open source computing project. Follow Andreas on Twitter.


Chip Architecture

  • ADC: Analog to Digital Converter
  • AES: Advanced encryption standard
  • Adder: Circuit to add two numbers
  • ALU: Arithmetic logic unit
  • Amdahl’s Law: Amdahl’s law of diminishing returns for speeding up fixed workloads
  • Arbiter: Arbitrates between competing requesters
  • ASIC: Application specific integrated circuit.
  • Audio codec: Device/program that compresses/decompresses digital audio
  • Boolean algebra: Algebra in which variables are either true or false
  • BTB: Branch target buffer
  • Cache: Locally storage of program and/or data for future use.
  • Cache coherence: Consistency of shared data that is stored in multiple local caches.
  • CAM: Content addressable memory
  • CISC: Complex instruction set computing
  • Coprocessor: A processor used to supplement operations of a primary (host) processor.
  • CPI: Cycles per instruction
  • CPU: Central processing unit
  • CRC: Cyclic redundancy check
  • CSA: Carry save adder
  • DAC: Digital to Analog Converter
  • Distributed Computing: Computer with components working towards common goal with without strict coupling.
  • DLL: Delay locked loop
  • DMA: Direct memory access
  • DDR Double data rate
  • DDS: Direct digital synthesis
  • DSM: Distributed shared memory
  • DSP: Digital signal processor
  • ECC: Error correcting code
  • Ethernet: Family of standard network technologies
  • Fault Tolerance: The ability of a system to keep operating in the event of failure of one of its components.
  • FRAM: Non-volatile RAM based on ferroelectric layer.
  • FPGA: Field-programmable gate array is a chip that can be reprogrammed “in the field”.
  • FIFO: First in first out buffer
  • GPU: Integrated circuit for accelerating the creation of graphics on a display.
  • DRAM: Dynamic random-access semiconductor memory
  • Flash: Non-volatile semiconductor memory
  • FFT: Fast fourier transform
  • FPU: Floating point unit
  • GPIO: IO controllale at run time
  • Gray code: Binary system where successive values differ by one bit
  • HBM: High bandwidth memory
  • I2C: Multi-master 2 wire bus
  • LAN: Local area network
  • LFSR: Linear feedback shift register
  • LSB: Least significant bit
  • LVDS: Low-voltage differential signaling (also TIA/EIA-644)
  • MII: Media independent interface for PHY chips
  • MIMD: Multiple instructionbs multiple data architecture
  • MMU: Memory management unit
  • MSB: Most significant bit
  • MUX: Multiplexer
  • Multiplier: Binary multiplier
  • NCO: Numerically controlled oscillator
  • NOC: Network on a chip
  • Parallel Computing: A type of computation where many operations are carried out simultanesouly.
  • PCM: Phase change memory
  • PCIe: High Speed serial computer expansion bus
  • PIC: Programmable interrupt controller
  • PLL: Phase locked loop
  • PWM: Pulse width modulation
  • Q: Q fixed point number format
  • RAID: Redundant array of disks
  • Reconfigurable Computing: Collection of customizable datapaths connected together by a fabric
  • RISC: Reduced instruction set computing
  • ROM: Read only memory (denser than RAM)
  • SBC: Single board computers
  • SDR: Software defined radio
  • SERDES: Serializer/deserializer
  • Shift Register: Set of registars that shifts bits one position at a time
  • SIMD: Single instrution multiple data
  • Schmitt Trigger: Comparitor circuit wityh
  • SPI: Synchronous 4 wirem aster/slave interface
  • SRAM: Static random access semiconductor memory
  • TLB: Translation lookaside buffer
  • UART: Asynchronous 2 wire point to point interface
  • USB: 2 wire point to point 5 V interface
  • Video codec: Device/program that compresses/decompresses digital video
  • Virtual Memory: The automatic mapping of virtual program addresses to physical addresses
  • VLIW: Very long instruction level parallelism
  • WAN: Wide area network
  • WIFI: Wireless local area network
  • 8b10b: Code that maps 8-bits to 10bit DC balanced symbols

Chip Design

  • Antenna effect: Plasma induced gate oxide damage that can occur during semiconductor processing.
  • Asynchronous logic: Logic not governed by a clock circuit or global clock.
  • ATPG: Automatic test pattern generation
  • BIST: Built in Self Test
  • Chip: A set of electronic circuits on one small plate (“chip”) of semiconductor material, normally silicon.
  • Clock gating: Technique whereby clock in synchronous logic is shut off when idle.
  • CMOS: Complimentary metal-oxide semiconductor
  • Cross talk: The coupling of nearby signals on a chip, usually through capacitive coupling.
  • CTS: Clock tree synthesis
  • Domino logic: Fast clocked logic with reduced capacitive load
  • DEF: Design Exchange Format for layout
  • DFM: Extended DRC rules specifying how to make a high yielding design.
  • DFT: Design for test
  • Die: Small block of semiconductor material that can be cut (“diced”) from a silicon wafer.
  • DRC: Design Rule Constraints specifying manufacturing constraints.
  • DV: Design verification is the process of verifying that the logic design conforms to specification.
  • ECO: Engineering change order
  • EDA: Electronic Design Automation tools used to enhance chip design productivity.
  • EDA companies: List of EDA companies
  • Electromigration: Transport of material caused by the gradual movement of the ions in a conductor.
  • EMI: Electromagnetic interference.
  • ESD: Electrostatic discharge is the sudden flow of electricity between two electrically charged objects.
  • Fabless: The design and sale of semiconductor devices while outsourcing the manufacturing to 3rd party.
  • FEOL: Front end of line processing. Includes all chop processing up to but not including metal interconnect layers.
  • Flip-flop: A clocked circuit that has two stable states and can be used to store state information.
  • Foundry: Semiconductor company offering manufacturing services.
  • Full custom design: Design methodology involving layout and interconnection of individual transistors
  • GDSII: Binary format of design database sent to foundry.
  • HDL: Specialized hardware description lanaguage for describing electronic circuits.
  • Hold time: Minimum time synchronous input should hold steady after clock event.
  • IP: Semiconductor reusable design blocks containing author’s Intellectual Property.
  • IP Vendors: List of commercial semiconductor IP vendors.
  • ISI: Intersymbol interference
  • Jitter: Deviation from perfect periodicity.
  • Latchup: Short circuit due to creation of a low-impedance path between the power supply rails of a circuit.
  • Layout: Physical representation of an integrated circuit.
  • LEF: Standard Cell Library Exchange Format layout.
  • Logical Effort: Technique used to normalize (and optimize) digital circuits speed paths.
  • LVS: Layout Versus Schematic software checks that the layout is identical to the netlist.
  • Mask Works: Copyright law dedicated to 2D and 3D integrated circuit “layouts”.
  • Mealy machine: A finite state machine whose outputs depend on current state and the current inputs
  • MLS: Packaging and handling precautions for some semiconductors.
  • Moore Machine: Finite state machine whose outputs depend only on its current state.
  • Moore’s Law: Observation by Moore that the number of transistors in an IC doubles approximately every two years.
  • MOSFET: Metal oxide field effect transistor.
  • MOSIS: Foundry service project offering MPWs and low volume manufacturing.
  • MPW: Multi-project wafer service that integrates multiple designs on one reticle (aka “shuttle”).
  • MTBF: Mean time between failures
  • Multi-threshold CMOS: CMOS technology with multiple transistor types with different threshold voltages.
  • Optical proximity correction: Technique used to compensate for semiconductor diffraction/process effects.
  • Pass Transistor Logic: Logic that connects input to non-gate terminal of mosfet transistor
  • Physical design: Physical design flow (“layout”)
  • PDK: Process design kits consist of a set of minimum set of files needed to design in a specific process.
  • Power gating: Technique used to reduce leakage/standby power by shutting of the supply to the circuit.
  • P&R: Automated Place and Route of a circuit using an EDA tool
  • PVT Corners: Represents the extreme process, voltage, temperature that could occur in a given semiconductor process.
  • Radiation Hardening: Act of making devices resistant to damage caused by ionizing radiation
  • RTL: Design abstraction for digital circuit design
  • Setup time: Minimum time synchronous input should be ready before clock event.
  • SEU: Change of state caused by one single ionizing particle (ions, electrons, photons…).
  • Signoff: The final approval that the design is ready to be sent to foundry for manufacturing.
  • SOC: System On Chip
  • Spice: Open source analog electronic circuit simulator
  • STA: Method of computing the expected timing of a digital circuit without requiring full circuit simulation.
  • Standard Cell Design: Design process relying on a fixed set of standard cells.
  • Subthreshold Leakage: Current betwee source and drain in MOSFET when transistor is “off”.
  • Synchronous logic: Logic whose state is controlled by a synchronous clock
  • Synthesis: Translation of high level design description (eg Verilog) to a netlist format (eg standard cell gate level)
  • SystemC: Set of C+ class and macros for simulation. Commonly used for high level modeling and testing
  • Transistor: A semiconductor device used to amplify/switch electronic signals.
  • Tape-out: Act of sending photomask chip database (“layout”) to the manufacturer.
  • TCL: Scripting language used by most of the leading EDA chip design tools.
  • Verilog: Hardware description language (HDL)
  • VLSI: Very large Integrated Circuit (somewhat outdated term, everything is VLSI today)
  • Von Neumann architecture: Computer architecture in which instructions and data are stored in the same memory.


  • BEOL: Back end of line processing for connecting together devices using metal interconnects.
  • Dicing: Act of cutting up wafer into individual dies
  • FinFet: Non planar, double-gate transistor.
  • Photo-lithography: Process used in micro-fabrication to pattern parts of a thin film or the bulk of a substrate.
  • Photomasks: Opaque plates with holes or transparencies that allow light to shine through in a defined pattern.
  • Reticle: A set of photomasks used by a stepper to step and print patterns onto a silicon wafer.
  • Semiconductor Fabrication: Process used to create the integrated circuits
  • Silicon: Element (Si) forms the basis of the electronic revolution.
  • Silicon on insulator: Layered silicon–insulator–silicon with reduced parasitic capacitance.
  • Stepper: Machine that passes light through reticle onto the silicon wafer being processed.
  • TSV: Vertical electrical connection (via) passing completely through a silicon wafer or die.
  • Wafer: Thin slice of semiconductor material used in electronics for the fabrication of integrated circuits.
  • Wafer thinning: Wafer thickness reduction to allow for stacking and high density packaging.


  • 3D IC’s: The process of stacking integrated circuits and connecting them through TSVs.
  • BGA: Ball grid array is a type of surface-mount packaging (a chip carrier) used for integrated circuits.
  • BGA substrate: A miniaturized PCB that mates the silicon die to BGA pins.
  • Bumping: Placing of bumps on wafer/dies in preparation for package assembly
  • DIMM: Dual in lin memory module
  • Flip-chip: Method of bonding a silicon die to package using solder bumps
  • IC Assembly: Semiconductor die is encased in a supporting case “package”.
  • Interposer: Electrical interface used to spread a connection to a wider pitch.
  • Heat sink: A passive heat exchanger.
  • Heat pipe: Device for efficiently transferring heat between two solid interfaces
  • KGD: Known Good Die. Dies that have been completely tested at wafer probe.
  • Leadframe: Metal structure inside a chip package that carry signals from the die to the outside.
  • POP: Package on Package
  • SIP: System In Package
  • SMT: Technique whereby packaged chips are mounted directly onto the PCB surface.
  • Wirebond: Method of bonding a silicon die to a package using wires
  • WSI: Wafer scale integration


  • Arbitrary Waveform Generator: Electronic instrument used to generate arbitrary signal waveforms.
  • ATE: Automatic Test Equipment for testing integrated circuits
  • Burn-in: Process of screening parts for potential premature life time failures.
  • DIB: Device Interface Board for interfacng DUT to ATE. Also called DUT board, probe card, load board, PIB.
  • DMM: Electronic instrument for measuring voltage, current, and resistance.
  • DUT: Device under test
  • FIB: Focused ion beam
  • JTAG: Industry standard for verifying and testing/debugging printed circuit boards after manufacturing.
  • Logic Analyzer: Electronic instrument for capturing multiple digital signal from a system.
  • MCM: Multi-chip Module
  • Oscilloscope: Electronic instrument for tracking the change of an electrical signal over time.
  • Probe Card: A direct interface between electronic test systems and a semiconductor wafer
  • SEM: Scanning electron microscope
  • Spectrum Analyzer: Electronic instrument for measuring the power of the spectrum of an unknown signal.


  • Max Odendahl says:

    I missed multicore ; -)

  • Clock Domain Crossing

  • Jay says:

    Looks like Schmitt Trigger got garbled and should end with ‘with hysteresis’ and SystemC should say C++ instead of C+.

  • […] 200 chip definitions everyone should know – [Link] […]

  • Andreas says:

    It SMT is there, THT should be there too.

  • David Conrad says:

    Where’s NUMA?

  • Luis says:

    So, could you enlighten us as to what will be the three breakthroughs that are coming in 2016? 😉

  • joeblo says:

    BigEndian and LittleEndian are pretty important concepts.

  • Colin Curtin says:

    I2C synonyms: I²C, TWI (two wire interface)
    BLE: Bluetooth Low Energy

  • Tero Isannainen says:

    There’s Verilog mentioned, but nowadays SystemVerilog is more important, and then there is VHDL used in some companies. I don’t know why, but they do, still!

  • Actually Tero, it’s a culture thing. I use both VHDL and Verilog depending on the project. Europeans tend to do VHDL (possibly due to self-flagellation tenancies inherent in it’s ADA roots) and the US use verilog. Verilog is taught more because it is ‘simpler’ but it is FAR easier to make a massive SNAFU in verilog due to its limited compile-time checks. The strong typing enforcement of VHDL might be a PITA at first, but you grow to like the comfort it gives. If it compiles, then it’s far more likely to work. I’ve written verilog before, which compiled just fine, but the synthesis results were, erm, less than desirable.

    I find the whole thing odd – VHDL was designed as a documentation language for hardware BEFORE logic synthesis was possible. It was designed by the US military, and yet, most US companies now reject it in favour of, in my opinion, a more dangerous Verilog. Odd really. Maybe it’s just hard to hire grads in the US who have any working knowledge of VHDL at all?

    BTW, SystemVerilog is a dreadful language, stuffed with ill-fitting design constructs and is badly planned. It feels like every man and his dog just stuffed in their own verilog extensions, and said “yup, that a new language that. Job done!” It’s far too complex, disjoint and frankly horrible. For verification, it will be a mainstay because of the powerful constructs it allows. But be very wary – many commercial synthesis tools still don’t fully support all constructs. We tried to use SystemVerilog for a past ASIC design, and we ended up backing out many features and rewriting in pure Verilog in many places, simply because the synthesis didn’t work as expected. Tread with caution!

    Anyway, I’m a Brit, so I’m probably biased 🙂 Rest assured, all my future HDL-orientated projects will use verilog, but only to keep the majority happy, not because I like it 🙂

  • Tero Isannainen says:

    Yes Dave, it’s what people prefer and what they have used. I was pulling a leg a little bit with VHDL comment, sorry. Verilog is however closer to what I would prefer. For the synthesizable subset SystemVerilog fixes the main issues I have with Verilog. One item is too verbose syntax regarding ports (and pins). In Verilog you list the ports and then list them again with width attributes. Wildcards in instantiation are good for designers own subblocks.

    Another issue with Verilog is that it is missing aggregate data types. You should be able to collect related bit fields under the same name, as in VHDL and now in SystemVerilog. Then for DSP type designs, you really want to have separate signed and unsigned integers. Basic level type checking is enough (for me) regarding data types. What VHDL does is just too much for me, it is annoying. Type system in VHDL is bloated for RTL level use. The linting tools cover everything you need also for Verilog. In VHDL, the code becomes unreadable with all the type conversion boilerplate and then people just ignores the types and silently overloads the std_ulogic_vector. Basically the compiler should check that no data/info is destroyed in assignment. Zero extension is ok, as in SystemVerilog (‘b101), but compiler should not allow direct assignment of signed to unsigned, and it should not allow assigning 6 bits to 5 bit variable. I like the pragmatic approach to combinational and synchronous logic in SV, where you can just name your processes as always_comb and always_ff, since 99% of the time this is exactly what you want to have.

    I don’t have hands on experience (only little) with SystemVerilog, but looking at the language spec, it is easy to agree with your statement that it is bloated. My guess is that the language “designers” (after consulting their dogs) wanted to cover everything that existed in VHDL and then have everything needed for verification, HVL. SystemVerilog is two languages in one, and I think they are documenting it as such as well. However, getting all details right and also implemented them correctly in EDA tools, is a long road ahead. Meanwhile we just have to keep our design guidelines updated and use them. The issue with bloated language is that you can’t easily clean it up. The other way around is easy. However, in the end, it would be beneficial for the EDA companies and for the users, if EDA companies could concentrate on just one language and implement the tools to be as good as possible for that one language.

    On the complex and disjoint department, I don’t agree. For RTL designers, you learn the synthesizable subset, and for Verification you learn everything. Verification is inherently complicated, until we can raise abstraction from RTL level. Well, it’s complicated even after that, but a bit less painful. When you need constrained random, you are screwed by definition. From HDL to HVL the language should be disjoint, and that should be even embraced. The transactors between TB and DUT is where the overlap should exist, otherwise the semantics are so different that they should be disjoint. Maybe there is a communication issue with SystemVerilog characteristics?

    Unfortunately I don’t have facts about the class system in SystemVerilog (HVL), but lets do some guessing… They don’t support Duck Typing, and you have to build tall inheritance hierarchies. These big piles of inheritance creates a lot of unnecessary dependencies in you testbench code and it becomes unmanageable. Also you loose (in practice) the ability to reuse your testbenches from design to design. My key point for verification is that the HVL portion should be a dynamic language and not static. Taking the simulation performance hit here is justified by the fact that the Verification Engineers time is a scarce resource and should be optimized as well as possible.

    We, in Finland, have to tolerate and even learn all kinds of languages, even VHDL, since we are a small country. It would be nice to do Fixit with VHDL. Just kidding… 🙂

Leave a Reply