![SSDTR-ASIC technology](https://upload.wikimedia.org/wikipedia/commons/7/79/SSDTR-ASIC_technology.jpg)
An application-specific integrated circuit (ASIC ) is an
integrated circuit
An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...
(IC) chip customized for a particular use, rather than intended for general-purpose use, such as a chip designed to run in a
digital voice recorder or a high-efficiency
video codec
A video codec is software or hardware that compresses and decompresses digital video. In the context of video compression, ''codec'' is a portmanteau of ''encoder'' and ''decoder'', while a device that only compresses is typically called an '' ...
.
Application-specific standard product (ASSP) chips are intermediate between ASICs and industry standard integrated circuits like the
7400 series
The 7400 series of integrated circuits (ICs) are a popular logic family of transistor–transistor logic (TTL) logic chips.
In 1964, Texas Instruments introduced the SN5400 series of logic chips, in a ceramic semiconductor package. A lo ...
or the
4000 series.
ASIC chips are typically
fabricated using
metal-oxide-semiconductor (MOS) technology, as
MOS integrated circuit
upright=1.6, gate (G), body (B), source (S), and drain (D) terminals. The gate is separated from the body by an gate oxide">insulating layer (pink).
The metal–oxide–semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET), also ...
chips.
As feature sizes have shrunk and design tools improved over the years, the maximum complexity (and hence functionality) possible in an ASIC has grown from 5,000
logic gates to over 100 million. Modern ASICs often include entire
microprocessors
A microprocessor is a computer processor where the data processing logic and control is included on a single integrated circuit, or a small number of integrated circuits. The microprocessor contains the arithmetic, logic, and control circu ...
,
memory
Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembered, ...
blocks including
ROM
Rom, or ROM may refer to:
Biomechanics and medicine
* Risk of mortality, a medical classification to estimate the likelihood of death for a patient
* Rupture of membranes, a term used during pregnancy to describe a rupture of the amniotic sac
* ...
,
RAM
Ram, ram, or RAM may refer to:
Animals
* A male sheep
* Ram cichlid, a freshwater tropical fish
People
* Ram (given name)
* Ram (surname)
* Ram (director) (Ramsubramaniam), an Indian Tamil film director
* RAM (musician) (born 1974), Dutch
* ...
,
EEPROM,
flash memory and other large building blocks. Such an ASIC is often termed a SoC (
system-on-chip
A system on a chip or system-on-chip (SoC ; pl. ''SoCs'' ) is an integrated circuit that integrates most or all components of a computer or other electronic system. These components almost always include a central processing unit (CPU), memor ...
). Designers of digital ASICs often use a
hardware description language
In computer engineering, a hardware description language (HDL) is a specialized computer language used to describe the structure and behavior of electronic circuits, and most commonly, digital logic circuits.
A hardware description language en ...
(HDL), such as
Verilog
Verilog, standardized as IEEE 1364, is a hardware description language (HDL) used to model electronic systems. It is most commonly used in the design and verification of digital circuits at the register-transfer level of abstraction. It is als ...
or
VHDL
The VHSIC Hardware Description Language (VHDL) is a hardware description language (HDL) that can model the behavior and structure of digital systems at multiple levels of abstraction, ranging from the system level down to that of logic gate ...
, to describe the functionality of ASICs.
Field-programmable gate arrays (FPGA) are the modern-day technology improvement on
breadboards, meaning that they are not made to be application-specific as opposed to ASICs. Programmable logic blocks and programmable interconnects allow the same FPGA to be used in many different applications. For smaller designs or lower production volumes, FPGAs may be more cost-effective than an ASIC design, even in production. The
non-recurring engineering
Non-recurring engineering (NRE) cost refers to the one-time cost to research, design, develop and test a new product or product enhancement. When budgeting for a new product, NRE must be considered to analyze if a new product will be profitable. ...
(NRE) cost of an ASIC can run into the millions of dollars. Therefore, device manufacturers typically prefer FPGAs
for prototyping and devices with low production volume and ASICs for
very large production volumes where NRE costs can be
amortized
In computer science, amortized analysis is a method for analyzing a given algorithm's complexity, or how much of a resource, especially time or memory, it takes to execute. The motivation for amortized analysis is that looking at the worst-case ...
across many devices.
History
Early ASICs used
gate array
A gate array is an approach to the design and manufacture of application-specific integrated circuits (ASICs) using a prefabricated chip with components that are later interconnected into logic devices (e.g. NAND gates, flip-flops, etc.) according ...
technology. By 1967,
Ferranti
Ferranti or Ferranti International plc was a UK electrical engineering and equipment firm that operated for over a century from 1885 until it went bankrupt in 1993. The company was once a constituent of the FTSE 100 Index.
The firm was known ...
and Interdesign were manufacturing early
bipolar gate arrays. In 1967,
Fairchild Semiconductor introduced the Micromatrix family of bipolar
diode–transistor logic
Diode–transistor logic (DTL) is a class of digital circuits that is the direct ancestor of transistor–transistor logic. It is called so because the logic gating function (e.g., AND) is performed by a diode network and the amplifying function ...
(DTL) and
transistor–transistor logic Transistor–transistor logic (TTL) is a logic family built from bipolar junction transistors. Its name signifies that transistors perform both the logic function (the first "transistor") and the amplifying function (the second "transistor"), as o ...
(TTL) arrays.
Complementary metal-oxide-semiconductor (CMOS) technology opened the door to the broad commercialization of gate arrays. The first CMOS gate arrays were developed by Robert Lipp, in 1974 for International Microcircuits, Inc. (IMI).
Metal-oxide-semiconductor (MOS)
standard cell technology was introduced by Fairchild and
Motorola
Motorola, Inc. () was an American multinational telecommunications company based in Schaumburg, Illinois, United States. After having lost $4.3 billion from 2007 to 2009, the company split into two independent public companies, Motorol ...
, under the trade names Micromosaic and Polycell, in the 1970s. This technology was later successfully commercialized by
VLSI Technology
VLSI Technology, Inc., was an American company that designed and manufactured custom and semi-custom integrated circuits (ICs). The company was based in Silicon Valley, with headquarters at 1109 McKay Drive in San Jose. Along with LSI Logic, ...
(founded 1979) and
LSI Logic
LSI Logic Corporation, an American company founded in Milpitas, California, was a pioneer in the ASIC and EDA industries. It evolved over time to design and sell semiconductors and software that accelerated storage and networking in data center ...
(1981).
A successful commercial application of gate array circuitry was found in the low-end 8-bit
ZX81
The ZX81 is a home computer that was produced by Sinclair Research and manufactured in Dundee, Scotland, by Timex Corporation. It was launched in the United Kingdom in March 1981 as the successor to Sinclair's ZX80 and designed to be a low-cos ...
and
ZX Spectrum
The ZX Spectrum () is an 8-bit computing, 8-bit home computer that was developed by Sinclair Research. It was released in the United Kingdom on 23 April 1982, and became Britain's best-selling microcomputer.
Referred to during development as t ...
personal computer
A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or tec ...
s, introduced in 1981 and 1982. These were used by
Sinclair Research
Sinclair Research Ltd is a British consumer electronics company founded by Clive Sinclair in Cambridge. It was originally incorporated in 1973 as Westminster Mail Order Ltd, renamed Sinclair Instrument Ltd, then Science of Cambridge Ltd, then ...
(UK) essentially as a low-cost
I/O solution aimed at handling the
computer's graphics.
Customization occurred by varying a metal interconnect mask. Gate arrays had complexities of up to a few thousand gates; this is now called
mid-scale integration
An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Transistor count, Large ...
. Later versions became more generalized, with different
base dies customized by both metal and
polysilicon
Polycrystalline silicon, or multicrystalline silicon, also called polysilicon, poly-Si, or mc-Si, is a high purity, polycrystalline form of silicon, used as a raw material by the solar photovoltaic and electronics industry.
Polysilicon is produce ...
layers. Some base dies also include
random-access memory
Random-access memory (RAM; ) is a form of computer memory that can be read and changed in any order, typically used to store working data and machine code. A random-access memory device allows data items to be read or written in almost the ...
(RAM) elements.
Standard-cell designs
In the mid-1980s, a designer would choose an ASIC manufacturer and implement their design using the design tools available from the manufacturer. While third-party design tools were available, there was not an effective link from the third-party design tools to the
layout
Layout may refer to:
* Page layout, the arrangement of visual elements on a page
** Comprehensive layout (comp), a proposed page layout presented by a designer to their client
* Layout (computing), the process of calculating the position of obj ...
and actual semiconductor process performance characteristics of the various ASIC manufacturers. Most designers used factory-specific tools to complete the implementation of their designs. A solution to this problem, which also yielded a much higher density device, was the implementation of
standard cells.
Every ASIC manufacturer could create functional blocks with known electrical characteristics, such as
propagation delay
Propagation delay is the time duration taken for a signal to reach its destination. It can relate to networking, electronics or physics. ''Hold time'' is the minimum interval required for the logic level to remain on the input after triggering ed ...
, capacitance and inductance, that could also be represented in third-party tools. Standard-cell design is the utilization of these functional blocks to achieve very high gate density and good electrical performance. Standard-cell design is intermediate between and in terms of its non-recurring engineering and recurring component costs as well as performance and speed of development (including
time to market
In commerce, time to market (TTM) is the length of time it takes from a product being conceived until its being available for sale. The reason that time to market is so important is since being late erodes the addressable market into which prod ...
).
By the late 1990s,
logic synthesis
In computer engineering, logic synthesis is a process by which an abstract specification of desired circuit behavior, typically at register transfer level (RTL), is turned into a design implementation in terms of logic gates, typically by a com ...
tools became available. Such tools could compile
HDL descriptions into a gate-level
netlist
In electronic design, a netlist is a description of the connectivity of an electronic circuit. In its simplest form, a netlist consists of a list of the electronic components in a circuit and a list of the nodes they are connected to. A network ...
. Standard-cell
integrated circuit
An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...
s (ICs) are designed in the following conceptual stages referred to as
electronics design flow, although these stages overlap significantly in practice:
#
Requirements engineering
Requirements engineering (RE) is the process of defining, documenting, and maintaining requirements in the engineering design process. It is a common role in systems engineering and software engineering.
The first use of the term ''requiremen ...
: A team of design engineers starts with a non-formal understanding of the
required functions for a new ASIC, usually derived from
requirements analysis
In systems engineering and software engineering, requirements analysis focuses on the tasks that determine the needs or conditions to meet the new or altered product or project, taking account of the possibly conflicting requirements of the ...
.
#
Register-transfer level
In digital circuit design, register-transfer level (RTL) is a design abstraction which models a synchronous digital circuit in terms of the flow of digital signals (data) between hardware registers, and the logical operations performed on those ...
(RTL) design: The design team constructs a description of an ASIC to achieve these goals using a
hardware description language
In computer engineering, a hardware description language (HDL) is a specialized computer language used to describe the structure and behavior of electronic circuits, and most commonly, digital logic circuits.
A hardware description language en ...
. This process is similar to writing a computer program in a
high-level language
In computer science, a high-level programming language is a programming language with strong abstraction from the details of the computer. In contrast to low-level programming languages, it may use natural language ''elements'', be easier to use, ...
.
#
Functional verification
In electronic design automation, functional verification is the task of verifying that the logic design conforms to specification. Functional verification attempts to answer the question "Does this proposed design do what is intended?" This is a ...
: Suitability for purpose is verified by functional verification. This may include such techniques as
logic simulation
Logic simulation is the use of simulation software to predict the behavior of digital circuits and hardware description languages. Simulation can be performed at varying degrees of physical abstraction, such as at the transistor level, gate le ...
through
test bench
A test bench or testing workbench is an environment used to verify the correctness or soundness of a design or model.
The term has its roots in the testing of electronic devices, where an engineer would sit at a lab bench with tools for measurem ...
es,
formal verification
In the context of hardware and software systems, formal verification is the act of proving or disproving the correctness of intended algorithms underlying a system with respect to a certain formal specification or property, using formal metho ...
,
emulation
Emulation may refer to:
*Emulation (computing), imitation of behavior of a computer or other electronic system with the help of another type of system
:*Video game console emulator, software which emulates video game consoles
*Gaussian process em ...
, or creating and evaluating an equivalent pure
software
Software is a set of computer programs and associated documentation and data. This is in contrast to hardware, from which the system is built and which actually performs the work.
At the lowest programming level, executable code consists ...
model, as in
Simics
Simics is a full-system simulator or virtual platform used to run unchanged production binaries of the target hardware. Simics was originally developed by the Swedish Institute of Computer Science (SICS), and then spun off to Virtutech for commer ...
. Each verification technique has advantages and disadvantages, and most often several methods are used together for ASIC verification. Unlike most
FPGAs
A field-programmable gate array (FPGA) is an integrated circuit designed to be configured by a customer or a designer after manufacturinghence the term '' field-programmable''. The FPGA configuration is generally specified using a hardware de ...
, ASICs cannot be
reprogrammed once
fabricated and therefore ASIC designs that are not completely correct are much more costly, increasing the need for full
test coverage.
# Logic synthesis:
Logic synthesis
In computer engineering, logic synthesis is a process by which an abstract specification of desired circuit behavior, typically at register transfer level (RTL), is turned into a design implementation in terms of logic gates, typically by a com ...
transforms the RTL design into a large collection called of lower-level constructs called standard cells. These constructs are taken from a
standard-cell library consisting of pre-characterized collections of
logic gates performing specific functions. The standard cells are typically specific to the planned manufacturer of the ASIC. The resulting collection of standard cells and the needed electrical connections between them is called a gate-level
netlist
In electronic design, a netlist is a description of the connectivity of an electronic circuit. In its simplest form, a netlist consists of a list of the electronic components in a circuit and a list of the nodes they are connected to. A network ...
.
# Placement: The gate-level netlist is next processed by a
placement tool which places the standard cells onto a region of an
integrated circuit die representing the final ASIC. The placement tool attempts to find an
optimized placement of the standard cells, subject to a variety of specified constraints.
# Routing: An electronics
routing
Routing is the process of selecting a path for traffic in a network or between or across multiple networks. Broadly, routing is performed in many types of networks, including circuit-switched networks, such as the public switched telephone netw ...
tool takes the physical placement of the standard cells and uses the netlist to create the
electrical connection
Components of an electrical circuit are electrically connected if an electric current can run between them through an electrical conductor. An electrical connector is an electromechanical device used to create an electrical connection between ...
s between them. Since the
search space is large, this process will produce a "sufficient" rather than "
globally optimal" solution. The output is a file which can be used to create a set of
photomask
A photomask is an opaque plate with holes or transparencies that allow light to shine through in a defined pattern. They are commonly used in photolithography and the production of integrated circuits (ICs or "chips") in particular. Masks are used ...
s enabling a
semiconductor fabrication facility, commonly called a 'fab' or 'foundry' to
manufacture physical
integrated circuit
An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...
s. Placement and routing are closely interrelated and are collectively called
place and route
Place and route is a stage in the design of printed circuit boards, integrated circuits, and field-programmable gate arrays. As implied by the name, it is composed of two steps, placement and routing. The first step, placement, involves decidi ...
in electronics design.
# Sign-off: Given the final layout,
circuit extraction computes the
parasitic resistances and capacitances. In the case of a
digital circuit, this will then be further mapped into
delay information from which the circuit performance can be estimated, usually by
static timing analysis. This, and other final tests such as
design rule checking
In electronic design automation, a design rule is a geometric constraint imposed on circuit board, semiconductor device, and integrated circuit (IC) designers to ensure their designs function properly, reliably, and can be produced with acceptab ...
and
power analysis
Power analysis is a form of side channel attack in which the attacker studies the power consumption of a cryptographic hardware device. These attacks rely on basic physical properties of the device: semiconductor devices are governed by the ...
collectively called
signoff are intended to ensure that the device will function correctly over all extremes of the process, voltage and temperature. When this testing is complete the
photomask
A photomask is an opaque plate with holes or transparencies that allow light to shine through in a defined pattern. They are commonly used in photolithography and the production of integrated circuits (ICs or "chips") in particular. Masks are used ...
information is released for
chip fabrication
Semiconductor device fabrication is the process used to manufacture semiconductor devices, typically integrated circuit (IC) chips such as modern computer processors, microcontrollers, and memory chips such as NAND flash and DRAM that are pres ...
.
These steps, implemented with a level of skill common in the industry, almost always produce a final device that correctly implements the original design, unless flaws are later introduced by the physical fabrication process.
The design steps also called
design flow, are also common to standard product design. The significant difference is that standard-cell design uses the manufacturer's cell libraries that have been used in potentially hundreds of other design implementations and therefore are of much lower risk than a full custom design. Standard cells produce a
design density that is cost-effective, and they can also integrate
IP cores and
static random-access memory
Static random-access memory (static RAM or SRAM) is a type of random-access memory (RAM) that uses latching circuitry (flip-flop) to store each bit. SRAM is volatile memory; data is lost when power is removed.
The term ''static'' differe ...
(SRAM) effectively, unlike gate arrays.
Gate-array and semi-custom design
Gate array
A gate array is an approach to the design and manufacture of application-specific integrated circuits (ASICs) using a prefabricated chip with components that are later interconnected into logic devices (e.g. NAND gates, flip-flops, etc.) according ...
design is a manufacturing method in which diffused layers, each consisting of
transistor
upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink).
A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch e ...
s and other
active devices, are predefined and
electronics wafers containing such devices are "held in stock" or unconnected prior to the
metallization stage of the
fabrication process
Semiconductor device fabrication is the process used to manufacture semiconductor devices, typically integrated circuit (IC) chips such as modern computer processors, microcontrollers, and memory chips such as NAND flash and DRAM that are p ...
. The
physical design process defines the interconnections of these layers for the final device. For most ASIC manufacturers, this consists of between two and nine metal layers with each layer running perpendicular to the one below it. Non-recurring engineering costs are much lower than full custom designs, as
photolithographic
In integrated circuit manufacturing, photolithography or optical lithography is a general term used for techniques that use light to produce minutely patterned thin films of suitable materials over a substrate, such as a silicon wafer, to protect ...
masks are required only for the metal layers. Production cycles are much shorter, as metallization is a comparatively quick process; thereby accelerating
time to market
In commerce, time to market (TTM) is the length of time it takes from a product being conceived until its being available for sale. The reason that time to market is so important is since being late erodes the addressable market into which prod ...
.
Gate-array ASICs are always a compromise between rapid design and
performance as mapping a given design onto what a manufacturer held as a stock wafer never gives 100%
circuit utilization. Often difficulties in
routing
Routing is the process of selecting a path for traffic in a network or between or across multiple networks. Broadly, routing is performed in many types of networks, including circuit-switched networks, such as the public switched telephone netw ...
the interconnect require migration onto a larger array device with a consequent increase in the piece part price. These difficulties are often a result of the layout
EDA EDA or Eda may refer to:
Computing
* Electronic design automation
* Enterprise Desktop Alliance, a computer technology consortium
* Enterprise digital assistant
* Estimation of distribution algorithm
* Event-driven architecture
* Exploratory ...
software used to develop the interconnect.
Pure, logic-only gate-array design is rarely implemented by circuit designers today, having been almost entirely replaced by
field-programmable devices. The most prominent of such devices are
field-programmable gate arrays (FPGAs) which can be programmed by the user and thus offer minimal tooling charges, non-recurring engineering, only marginally increased piece part cost, and comparable performance.
Today, gate arrays are evolving into
structured ASICs that consist of a large
IP core
In electronic design, a semiconductor intellectual property core (SIP core), IP core, or IP block is a reusable unit of logic, cell, or integrated circuit layout design that is the intellectual property of one party. IP cores can be licensed to ...
like a
CPU,
digital signal processor
A digital signal processor (DSP) is a specialized microprocessor chip, with its architecture optimized for the operational needs of digital signal processing. DSPs are fabricated on MOS integrated circuit chips. They are widely used in audio si ...
units,
peripherals, standard
interfaces, integrated
memories
Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembered, ...
,
SRAM, and a block of
reconfigurable, uncommitted logic. This shift is largely because ASIC devices are capable of integrating large blocks of
system
A system is a group of Interaction, interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment (systems), environment, is described by its boundaries, ...
functionality, and
systems on a chip (SoCs) require
glue logic
In electronics, glue logic is the custom logic circuitry used to interface a number of off-the-shelf integrated circuits. This is often achieved using common, inexpensive 7400- or 4000-series components. In more complex cases, a programmable l ...
,
communications subsystems (such as
networks on chip),
peripherals, and other components rather than only
functional unit
In computer engineering, an execution unit (E-unit or EU) is a part of the central processing unit (CPU) that performs the operations and calculations as instructed by the computer program. It may have its own internal control sequence unit (not ...
s and basic interconnection.
In their frequent usages in the field, the terms "gate array" and "semi-custom" are synonymous when referring to ASICs.
Process engineers more commonly use the term "semi-custom", while "gate-array" is more commonly used by logic (or gate-level) designers.
Full-custom design
![VLSI VL82C486 Single Chip 486 System Controller HV](https://upload.wikimedia.org/wikipedia/commons/7/7b/VLSI_VL82C486_Single_Chip_486_System_Controller_HV.jpg)
By contrast, full-custom ASIC design defines all the photolithographic layers of the device.
Full-custom design is used for both ASIC design and for standard product design.
The benefits of full-custom design include reduced area (and therefore recurring component cost),
performance improvements, and also the ability to integrate
analog
Analog or analogue may refer to:
Computing and electronics
* Analog signal, in which information is encoded in a continuous variable
** Analog device, an apparatus that operates on analog signals
*** Analog electronics, circuits which use analog ...
components and other
pre-designed—and thus fully verified—components, such as
microprocessor
A microprocessor is a computer processor where the data processing logic and control is included on a single integrated circuit, or a small number of integrated circuits. The microprocessor contains the arithmetic, logic, and control circu ...
cores, that form a
system on a chip.
The disadvantages of full-custom design can include increased manufacturing and design time, increased non-recurring engineering costs, more complexity in the
computer-aided design
Computer-aided design (CAD) is the use of computers (or ) to aid in the creation, modification, analysis, or optimization of a design. This software is used to increase the productivity of the designer, improve the quality of design, improve c ...
(CAD) and
electronic design automation systems, and a much higher skill requirement on the part of the design team.
For digital-only designs, however, "standard-cell" cell libraries, together with modern CAD systems, can offer considerable performance/cost benefits with low risk. Automated layout tools are quick and easy to use and also offer the possibility to "hand-tweak" or manually optimize any performance-limiting aspect of the design.
This is designed by using basic logic gates, circuits or layout specially for a design.
Structured design
''Structured ASIC design'' (also referred to as "''platform ASIC design''") is a relatively new trend in the semiconductor industry, resulting in some variation in its definition. However, the basic premise of a structured ASIC is that both manufacturing cycle time and design cycle time are reduced compared to cell-based ASIC, by virtue of there being pre-defined metal layers (thus reducing manufacturing time) and pre-characterization of what is on the silicon (thus reducing design cycle time).
Definition from Foundations of Embedded Systems states that:
This is effectively the same definition as a gate array. What distinguishes a structured ASIC from a gate array is that in a gate array, the predefined metal layers serve to make manufacturing turnaround faster. In a structured ASIC, the use of predefined metallization is primarily to reduce cost of the mask sets as well as making the design cycle time significantly shorter.
For example, in a cell-based or gate-array design the user must often design power, clock, and test structures themselves. By contrast, these are predefined in most structured ASICs and therefore can save time and expense for the designer compared to gate-array based designs. Likewise, the design tools used for structured ASIC can be substantially lower cost and easier (faster) to use than cell-based tools, because they do not have to perform all the functions that cell-based tools do. In some cases, the structured ASIC vendor requires customized tools for their device (e.g., custom physical synthesis) be used, also allowing for the design to be brought into manufacturing more quickly.
Cell libraries, IP-based design, hard and soft macros
Cell libraries of logical primitives are usually provided by the device manufacturer as part of the service. Although they will incur no additional cost, their release will be covered by the terms of a
non-disclosure agreement
A non-disclosure agreement (NDA) is a legal contract or part of a contract between at least two parties that outlines confidential material, knowledge, or information that the parties wish to share with one another for certain purposes, but wish ...
(NDA) and they will be regarded as intellectual property by the manufacturer. Usually, their physical design will be pre-defined so they could be termed "hard macros".
What most engineers understand as "
intellectual property
Intellectual property (IP) is a category of property that includes intangible creations of the human intellect. There are many types of intellectual property, and some countries recognize more than others. The best-known types are patents, cop ...
" are
IP cores, designs purchased from a third-party as sub-components of a larger ASIC. They may be provided in the form of a
hardware description language
In computer engineering, a hardware description language (HDL) is a specialized computer language used to describe the structure and behavior of electronic circuits, and most commonly, digital logic circuits.
A hardware description language en ...
(often termed a "soft macro"), or as a fully routed design that could be printed directly onto an ASIC's mask (often termed a "hard macro"). Many organizations now sell such pre-designed cores – CPUs, Ethernet, USB or telephone interfaces – and larger organizations may have an entire department or division to produce cores for the rest of the organization. The company
ARM
In human anatomy, the arm refers to the upper limb in common usage, although academically the term specifically means the upper arm between the glenohumeral joint (shoulder joint) and the elbow joint. The distal part of the upper limb between th ...
(Advanced
RISC Machines) ''only'' sells IP cores, making it a
fabless manufacturer.
Indeed, the wide range of functions now available in structured ASIC design is a result of the phenomenal improvement in electronics in the late 1990s and early 2000s; as a core takes a lot of time and investment to create, its
re-use
Reuse is the action or practice of using an item, whether for its original purpose (conventional reuse) or to fulfill a different function ( creative reuse or repurposing). It should be distinguished from recycling, which is the breaking down of u ...
and further development cuts product cycle times dramatically and creates better products. Additionally,
open-source hardware organizations such as
OpenCores
OpenCores is a community developing digital open-source hardware through electronic design automation (EDA), with a similar ethos as the free software movement. OpenCores hopes to eliminate redundant design work and slash development costs. A ...
are collecting free IP cores, paralleling the
open-source software
Open-source software (OSS) is computer software that is released under a license in which the copyright holder grants users the rights to use, study, change, and distribute the software and its source code to anyone and for any purpose. Op ...
movement in hardware design.
Soft macros are often process-independent (i.e. they can be fabricated on a wide range of manufacturing processes and different manufacturers). Hard macros are process-limited and usually further design effort must be invested to migrate (port) to a different process or manufacturer.
Multi-project wafers
Some manufacturers and IC design houses offer
multi-project wafer service Multi-project chip (MPC), and multi-project wafer (MPW) semiconductor manufacturing arrangements allow customers to share mask and microelectronics wafer fabrication cost between several designs or projects.
With the MPC arrangement, one chip is a ...
(MPW) as a method of obtaining low cost prototypes. Often called shuttles, these MPWs, containing several designs, run at regular, scheduled intervals on a "cut and go" basis, usually with limited liability on the part of the manufacturer. The contract involves delivery of bare dies or the assembly and packaging of a handful of devices. The service usually involves the supply of a physical design database (i.e. masking information or pattern generation (PG) tape). The manufacturer is often referred to as a "silicon foundry" due to the low involvement it has in the process.
Application-specific standard product
![Kyocera FS-C5200DN - interface board - Renesas M66591GP-4189](https://upload.wikimedia.org/wikipedia/commons/7/74/Kyocera_FS-C5200DN_-_interface_board_-_Renesas_M66591GP-4189.jpg)
An application-specific standard product or ASSP is an
integrated circuit
An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...
that implements a specific
function
Function or functionality may refer to:
Computing
* Function key, a type of key on computer keyboards
* Function model, a structured representation of processes in a system
* Function object or functor or functionoid, a concept of object-oriente ...
that appeals to a wide market. As opposed to ASICs that combine a collection of functions and are designed by or for one
customer, ASSPs are available as off-the-shelf components. ASSPs are used in all industries, from automotive to communications. As a general rule, if you can find a
design
A design is a plan or specification for the construction of an object or system or for the implementation of an activity or process or the result of that plan or specification in the form of a prototype, product, or process. The verb ''to design'' ...
in a data
book
A book is a medium for recording information in the form of writing or images, typically composed of many pages (made of papyrus, parchment, vellum, or paper) bound together and protected by a cover. The technical term for this physical arr ...
, then it is probably not an ASIC, but there are some exceptions.
For example, two ICs that might or might not be considered ASICs are a controller chip for a PC and a chip for a
modem
A modulator-demodulator or modem is a computer hardware device that converts data from a digital format into a format suitable for an analog transmission medium such as telephone or radio. A modem transmits data by Modulation#Digital modulati ...
. Both of these examples are specific to an application (which is typical of an ASIC) but are sold to many different system vendors (which is typical of standard parts). ASICs such as these are sometimes called application-specific standard products (ASSPs).
Examples of ASSPs are encoding/decoding chip, Ethernet network interface controller chip, etc.
IEEE
The Institute of Electrical and Electronics Engineers (IEEE) is a 501(c)(3) professional association for electronic engineering and electrical engineering (and associated disciplines) with its corporate office in New York City and its operation ...
used to publish an ASSP magazine,
IEEE ASSP Issue 2, Part 1 – April 1984
/ref> which was renamed to IEEE Signal Processing Magazine in 1990.
See also
* Application-specific instruction set processor
An application-specific instruction set processor (ASIP) is a component used in system on a chip design. The instruction set architecture of an ASIP is tailored to benefit a specific application. This specialization of the core provides a tradeo ...
(ASIP)
* Complex programmable logic device (CPLD)
* Electronic design automation (EDA or ECAD)
* Field-programmable gate array (FPGA)
* Multi-project chip (MPC)
* Very Large Scale Integration
Very large-scale integration (VLSI) is the process of creating an integrated circuit (IC) by combining millions or billions of MOS transistors onto a single chip. VLSI began in the 1970s when MOS integrated circuit (Metal Oxide Semiconductor) ...
(VLSI)
* System on a chip (SoC)
* Hardware acceleration for an overview of computing based primarily in hardware
References
Sources
*
*
*
*
External links
*
{{Authority control
Gate arrays
Integrated circuits
Hardware acceleration