Daughterboard - AbsoluteAstronomy.com

A daughterboard, daughtercard or piggyback board is a circuit board meant to be an extension or "daughter" of a motherboard

Motherboard

In personal computers, a motherboard is the central printed circuit board in many modern computers and holds many of the crucial components of the system, providing connectors for other peripherals. The motherboard is sometimes alternatively known as the mainboard, system board, or, on Apple...

(or 'mainboard'), or occasionally of another card. In particular, daughterboards often have plugs, sockets

Jack (connector)

In electronics and electrical assemblies, the term jack commonly refers to a surface-mounted connector, often, but not always, with the female electrical contact or socket, and is the "more fixed" connector of a connector pair...

, pins, connectors

Electrical connector

An electrical connector is an electro-mechanical device for joining electrical circuits as an interface using a mechanical assembly. The connection may be temporary, as for portable equipment, require a tool for assembly and removal, or serve as a permanent electrical joint between two wires or...

, or other attachments for other boards, which is what differentiates them from a standard expansion board such as for PCI

Peripheral Component Interconnect

Conventional PCI is a computer bus for attaching hardware devices in a computer...

or ISA

Industry Standard Architecture

Industry Standard Architecture is a computer bus standard for IBM PC compatible computers introduced with the IBM Personal Computer to support its Intel 8088 microprocessor's 8-bit external data bus and extended to 16 bits for the IBM Personal Computer/AT's Intel 80286 processor...

. In addition, daughterboards usually have only internal connections

Electrical connector

within a computer

Computer

A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...

or other electronic

Electronics

Electronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...

device

Machine

A machine manages power to accomplish a task, examples include, a mechanical system, a computing system, an electronic system, and a molecular machine. In common usage, the meaning is that of a device having parts that perform or assist in performing any type of work...

rather than any external ones, and usually access the motherboard directly rather than through a computer bus

Computer bus

In computer architecture, a bus is a subsystem that transfers data between components inside a computer, or between computers.Early computer buses were literally parallel electrical wires with multiple connections, but the term is now used for any physical arrangement that provides the same...

.

Daughterboards are sometimes used in computers in order to allow for expansion card

Expansion card

The expansion card in computing is a printed circuit board that can be inserted into an expansion slot of a computer motherboard or backplane to add functionality to a computer system via the expansion bus.One edge of the expansion card holds the contacts that fit exactly into the slot...

s to fit on their side (or upright), parallel

Parallel (geometry)

Parallelism is a term in geometry and in everyday life that refers to a property in Euclidean space of two or more lines or planes, or a combination of these. The assumed existence and properties of parallel lines are the basis of Euclid's parallel postulate. Two lines in a plane that do not...

to the motherboard, usually to maintain a small or slim form factor. In this case they can also be called riser card

Riser card

A riser card is a printed circuit board that picks up a multitude of signal lines via a single connector on a mainboard and distributes them via dedicated connectors on the card....

s, or risers. Daughterboards are also sometimes used to expand the basic functionality of an electronic device, such as when a certain model has features added to it and is released as a new or separate model. Rather than redesign the first model completely, a daughterboard may be added to a special port

Computer port (hardware)

In computer hardware, a port serves as an interface between the computer and other computers or peripheral devices. Physically, a port is a specialized outlet on a piece of equipment to which a plug or cable connects...

or connector on the motherboard or mainboard. These usually fit on top of and parallel to the board, separated by spacer

Spacer

Spacer may refer to:* Spacer , in Isaac Asimov's Robot Series* Rebar spacer, in concrete construction* Spacer, alias for flesh tunnel, a type of body piercing* Spacer, element in HTML Webpage designIn science and medicine:...

s or standoffs, and are therefore sometimes called mezzanine cards due to being stacked like the mezzanine

Mezzanine (architecture)

In architecture, a mezzanine or entresol is an intermediate floor between main floors of a building, and therefore typically not counted among the overall floors of a building. Often, a mezzanine is low-ceilinged and projects in the form of a balcony. The term is also used for the lowest balcony in...

of a theatre

Theatre

Theatre is a collaborative form of fine art that uses live performers to present the experience of a real or imagined event before a live audience in a specific place. The performers may communicate this experience to the audience through combinations of gesture, speech, song, music or dance...

. Wavetable cards are often mounted on sound card

Sound card

A sound card is an internal computer expansion card that facilitates the input and output of audio signals to and from a computer under control of computer programs. The term sound card is also applied to external audio interfaces that use software to generate sound, as opposed to using hardware...

s in this manner.

Use of the names daughter card and daughter board, and even mezzanine board are also acceptable.

Types

Enhanced Graphics Adapter
Enhanced Graphics Adapter
The Enhanced Graphics Adapter is the IBM PC computer display standard specification which is between CGA and VGA in terms of color and space resolution. Introduced in October 1984 by IBM shortly after its new PC/AT, EGA produces a display of 16 simultaneous colors from a palette of 64 at a...

piggyback board, adds memory beyond 64 KB, up to 256 KB
Expanded memory
Expanded memory
In DOS memory management, expanded memory is a system of bank switching introduced April 24, 1985 that provided additional memory to DOS programs beyond the limit of conventional memory. Expanded memory uses parts of the address space normally dedicated to communication with peripherals for program...

piggyback board, adds additional memory to some EMS and EEMS boards
ADD daughterboard
RAID daughterboard
10/100Base-T Ethernet daughterboard
CPU Socket daughterboard
Bluetooth daughterboard
Modem daughterboard
AD/DA/DIO daughter-card
Communication daughterboard (CDC)
Server Management daughterboard (SMDC)
Serial ATA connector daughterboard
Robotic daughterboard
Access control List daughterboard

Types

See also