In
electronics
Electronics is a scientific and engineering discipline that studies and applies the principles of physics to design, create, and operate devices that manipulate electrons and other Electric charge, electrically charged particles. It is a subfield ...
, pin-compatible devices are
electronic component
An electronic component is any basic discrete electronic device or physical entity part of an electronic system used to affect electrons or their associated fields. Electronic components are mostly industrial products, available in a singula ...
s, generally
integrated circuit
An integrated circuit (IC), also known as a microchip or simply chip, is a set of electronic circuits, consisting of various electronic components (such as transistors, resistors, and capacitors) and their interconnections. These components a ...
s or
expansion card
In computing, an expansion card (also called an expansion board, adapter card, peripheral card or accessory card) is a printed circuit board that can be inserted into an electrical connector, or expansion slot (also referred to as a bus sl ...
s, sharing a common
footprint and with the same functions assigned or usable on the same
pins.
Pin compatibility is a property desired by
systems integrators as it allows a product to be updated without redesigning
printed circuit board
A printed circuit board (PCB), also called printed wiring board (PWB), is a Lamination, laminated sandwich structure of electrical conduction, conductive and Insulator (electricity), insulating layers, each with a pattern of traces, planes ...
s, which can reduce costs and decrease
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 that being late erodes the addressable market into which produ ...
.
Although devices which are pin-compatible share a common footprint, they are not necessarily electrically or thermally compatible. As a result, manufacturers often specify devices as being either ''pin-to-pin'' or ''drop-in'' compatible.
Pin-compatible devices are generally produced to allow upgrading within a single
product line
In marketing jargon, product lining refers to the offering of several related product (business), products for individual sale. Unlike product bundling, where several products are combined into one group, which is then offered for sale as a uni ...
, to allow
end-of-life devices to be replaced with newer equivalents, or to compete with the equivalent products of other manufacturers.
Pin-to-pin compatibility
''Pin-to-pin compatible'' devices share an assignment of functions to pins, but may have differing electrical characteristics (supply
voltage
Voltage, also known as (electrical) potential difference, electric pressure, or electric tension, is the difference in electric potential between two points. In a Electrostatics, static electric field, it corresponds to the Work (electrical), ...
s, or
oscillator
Oscillation is the repetitive or periodic variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states. Familiar examples of oscillation include a swinging pendulum ...
frequencies) or thermal characteristics (
TDPs,
reflow curves, or
temperature tolerances). As a result, their use in a system may require that portions of the system, such as its power delivery subsystem, be adapted to fit the new component.
A common example of pin-to-pin compatible devices which may not be electrically compatible are the
7400 series
The 7400 series is a popular logic family of transistor–transistor logic (TTL) integrated circuits (ICs).
In 1964, Texas Instruments introduced the SN5400 series of logic chips, in a ceramic semiconductor package. A low-cost plastic package ...
integrated circuits. The 7400 series devices have been produced on a number of different manufacturing processes, but have retained the same
pinouts throughout. For example, all 7405 devices provide six
NOT gate
Not or NOT may also refer to:
Language
* Not, the general declarative form of "no", indicating a negation of a related statement that usually precedes
* ... Not!, a grammatical construction used as a contradiction, popularized in the early 1990 ...
s (or inverters) but may have incompatible supply voltage tolerances.
* 7405 – Standard
TTL, 4.75–5.25 V.
* 74C05 –
CMOS
Complementary metal–oxide–semiconductor (CMOS, pronounced "sea-moss
", , ) is a type of MOSFET, metal–oxide–semiconductor field-effect transistor (MOSFET) semiconductor device fabrication, fabrication process that uses complementary an ...
, 4–15 V.
* 74LV05 – Low-voltage CMOS, 2.0–5.5 V.
In other cases, particularly with
computer
A computer is a machine that can be Computer programming, programmed to automatically Execution (computing), carry out sequences of arithmetic or logical operations (''computation''). Modern digital electronic computers can perform generic set ...
s, devices may be pin-to-pin compatible but made otherwise incompatible as a result of
market segmentation
In marketing, market segmentation or customer segmentation is the process of dividing a consumer or business market into meaningful sub-groups of current or potential customers (or consumers) known as ''segments''. Its purpose is to identify pr ...
. For example,
Intel Skylake desktop-class
Core and
Xeon E3v5 processors both use the
LGA 1151 socket, but
motherboard
A motherboard, also called a mainboard, a system board, a logic board, and informally a mobo (see #Nomenclature, "Nomenclature" section), is the main printed circuit board (PCB) in general-purpose computers and other expandable systems. It ho ...
s using C230-series
chipset
In a computer system, a chipset is a set of electronic components on one or more integrated circuits that manages the data flow between the processor, memory and peripherals. The chipset is usually found on the motherboard of computers. Chips ...
s will only be compatible with Xeon-branded processors, and will not work with Core-branded processors.
Drop-in compatibility
A ''drop-in compatible'' device is a device which may be swapped with another without need to make compensating alterations to the system the device was a part of. The device will have the same functions available on the same pins, and will be electrically and thermally compatible. Such devices may not be an exact match to the devices they can replace. For example, they may have a wider range of supply voltage or temperature tolerances.
Software compatibility
''Software-compatible'' devices are devices which are able to run the same software to produce the same results without the software having to be modified first.
Microcontroller
A microcontroller (MC, uC, or μC) or microcontroller unit (MCU) is a small computer on a single integrated circuit. A microcontroller contains one or more CPUs (processor cores) along with memory and programmable input/output peripherals. Pro ...
s,
FPGA
A field-programmable gate array (FPGA) is a type of configurable integrated circuit that can be repeatedly programmed after manufacturing. FPGAs are a subset of logic devices referred to as programmable logic devices (PLDs). They consist of a ...
s, and other programmable devices may be pin-to-pin compatible from the perspective of the program on the device, but incompatible in terms of hardware. For example, the device may take the signal on pin X,
negate it, and output the result on pin Y. If the method of configuring a pin remains the same but the
package of the device (such as
TSSOP or
QFN) changes, the program will continue to function but the physical locations of the pins the program works with may change.
A device may also be pin-compatible while being software-incompatible. This may occur when the device uses a different
instruction set
In computer science, an instruction set architecture (ISA) is an abstract model that generally defines how software controls the CPU in a computer or a family of computers. A device or program that executes instructions described by that ISA, s ...
, or if the device has a
multiplexer
In electronics, a multiplexer (or mux; spelled sometimes as multiplexor), also known as a data selector, is a device that selects between several Analog signal, analog or Digital signal (electronics), digital input signals and forwards the sel ...
attached to a pin (which, for example, may allow the switching of the pin between being driven as
GPIO or by an
A/D) and that multiplexer selects, by default, a different input source than is selected on the device being replaced.
To ease the use of software-incompatible devices, manufacturers often provide
hardware abstraction layers. Examples of these include,
CMSIS for
ARM Cortex-M processors and the now-deprecated
HAL subsystem for
UNIX-like
A Unix-like (sometimes referred to as UN*X, *nix or *NIX) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Uni ...
operating systems.
See also
*
7400 series
The 7400 series is a popular logic family of transistor–transistor logic (TTL) integrated circuits (ICs).
In 1964, Texas Instruments introduced the SN5400 series of logic chips, in a ceramic semiconductor package. A low-cost plastic package ...
integrated circuits
*
Programmable logic
*
Logic family
In computer engineering, a logic family is one of two related concepts:
* A logic family of monolithic digital integrated circuit devices is a group of electronic logic gates constructed using one of several different designs, usually with compati ...
*
Semiconductor packages
References
{{reflist, colwidth=30em
External links
Giant Internet IC Master Database– A list of 74'xx series and other generic chip pinouts.
Integrated circuits
Interoperability