Dual in-line package
The English term Dual in-line package ( acronym DIP , also Dual In-Line , short DIL , dt. »Double row housing«) is an elongated housing form (English package ) for electronic components in which two rows of connecting pins (pins ) for push-through mounting are located on opposite sides of the housing.
Function and application
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The connection pins are designed to be pushed through holes in a circuit board and soldered from the bottom. In the case of single-layer circuit boards and multi - layer circuit boards with through- hole contacts, this makes it possible to solder the components by wave soldering, in contrast to surface-mounted housings on top .
Components in DIP housings can also be used with plug-in sockets so that they can be exchanged. DIP is the classic housing design for integrated circuits . However, there are also other components in DIP housings, such as relays , small switches ( DIP switches ) or resistor networks . The housings usually have between 6 and 64 pins and a body made of plastic or ceramic . The ceramic version is also known as CERDIP (in contrast to PDIP for plastic coating).
Four or six-legged housings are often used for optocouplers .
In contrast to the DIP housing, a single in-line package (SIP / SIL, i.e. single-row housing ) has only one row of connection pins for through-hole mounting. Both with DIP and SIP there are designs in which the pins within the row are arranged offset to one another in a zigzag, i.e. alternately by a grid dimension further outside or inside, which means that the soldering eyes or their spacing can be larger. Such SIP designs are also called ZIP.
Due to the increasing miniaturization and the increasing number of connections required for integrated circuits , the use of the DIP housing has declined sharply since the 1990s. However DIP package in are the prototype stage useful because, in contrast to SMD -Bauelementen well by hand on breadboards can be used (for experimental purposes PCBs with Lötaugen- or hole pattern).
Typical dimensions
Most DIPs have a 2.54 mm ( 1 ⁄ 10 " ) pitch and a row spacing of 7.62 ( 3 ⁄ 10 ") or 15.24 mm ( 6 ⁄ 10 "). Because the pins are arranged in two rows, all types have an even number of pins. The 7.62 mm variant usually has 8 to 20 pins. The 15.24 mm variant is equipped with 32 to 64 pins. DIPs with 24 and 28 pins come in both variants.
The JEDEC standard also provides for less common variants with 10.16 or 22.86 mm row spacing. Other standardized variants have a pin spacing of 1.778 mm.
Components with a pin grid of 2 mm and a row spacing of 5.35 mm are also rarely found.
Pin assignment
By default, the chips are shown in sketches in a view from above ("component side"), as shown in the picture with the 7400 in the transverse direction, so that the imprint can be read directly. The notch in one of the narrow sides of the housing is always on the left. At the bottom left of this notch the counting of the pins starts at 1 and then goes counterclockwise around the chip to the top left. Pin 1 is also usually identified by a printed or embossed marking.
The assignment of the power supply for digital circuits mostly follows the standard that the ground on the bottom right and the positive operating voltage on the top left are connected directly next to the notch. Because of this standardization, it is also worthwhile to offer plug-in sockets for these ICs with built-in backup capacitors .
DIL versus SMD or SO
As the components for surface mount (Engl. Surface mounted device , SMD) established, demand rose sharply after surface mount circuits (SMD IC). In order to be able to meet the demand and to be able to sell the DIP circuits already produced, the manufacturers began to convert DIPs into SMDs by bending the pins below the lower edge of the component body outwards at right angles . An SMD variant with DIL dimensions was created, but was rarely used at the end of the 1980s. At the same time, Plastic Leaded Chip Carriers (PLCC) appeared, with the pins under the housing bent inwards . As a special feature, PLCC are one of the few SMD housing variants for which sockets are available as standard .
Later, the switch to SMD consistently led to miniaturization and to the smaller SMD pitches of 1.27 mm or 0.65 mm of the connector legs, which were now bent outwards again for SO designs (such as SOP from small outline package or TSSOP from thin shrink small outline package ). The new assembly technology required new manufacturing and assembly machines, but saves space and housing material, requires less precise meeting of the soldering islands during assembly (the holes for DIL components were often drilled conically in single-layer circuit boards in order to meet them securely with the connection legs).
The above standards for pin assignment have been adopted unchanged for the SMD variants on the smaller scale.
In 2004, many older and standard ICs were still available in DIL housings. Individual ICs were even only available in DIL housings, so that you can often find mixed assemblies (SMD and through-hole assembly) on the circuit boards .
With numerous newly developed components, only the SMD designs are often offered. This is especially true for components that are supposed to work with a high clock frequency (such as processors ). Due to the larger dimensions of the DIL housing and the associated cable lengths, these components cannot be operated at very high frequencies if fast data lines such as buses are to be led out. Despite the dominance of SMD components, new microcontrollers in DIL packages came onto the market even in 2013 . A great advantage of DIL housings for microcontrollers and other programmable ICs is that they can be plugged into sockets in order to program them, while additional components (e.g. sockets) must be provided for programming for SMD components.
DIL circuits are better suited for building prototypes, test circuits or small series , as they can be soldered by hand without any problems. Despite the higher material requirements, DIL designs of the same chips are hardly more expensive today, and sometimes even cheaper than SMD. One reason may be that DIL components have to withstand lower temperature loads when soldered than SMD.
Individual evidence
- ↑ LPC1114FN28. In: Products / Microcontrollers / Cortex-M0. NXP Semiconductors, January 7, 2013, accessed September 30, 2018 (English, 32-bit ARM Cortex-M0 microcontroller; 32 kB flash and 4 kB SRAM).
