Papan sirkuit anu dicitak (PCB) aya dina ampir unggal jenis alat éléktronik. If there are electronic components in a piece of equipment, they are also embedded in various sizes of PCB. In addition to fixing various small parts, the main function of the PCB is to provide electrical connections between the components. As electronic equipment becomes more and more complex, more and more parts are needed, and the wiring and parts on the PCB become more and more dense. A standard PCB looks something like this. Bare Board (without parts on it) is also often referred to as “Printed Wiring Board (PWB).

The substrate of the board itself is made of a material that is insulated and resistant to bending. The small line material that can be seen on the surface is copper foil. Originally, the copper foil is covered on the whole board, and the middle part is etched away in the manufacturing process, and the remaining part becomes a network of small lines. These lines are called conductors or conductors and are used to provide electrical connections to parts on the PCB.

To secure parts to the PCB, we solder their pins directly to the wiring. Dina PCB dasar, bagian-bagianna konséntrasi dina hiji sisi sareng kabel-kabelna pekat dina sisi anu sanés. So we need to make holes in the board so that the pins can go through the board to the other side, so the pins of the parts are welded to the other side. Because of this, the front and back sides of a PCB are called Component Side and Solder Side respectively.

Upami aya bagian-bagian dina PCB anu tiasa dipiceun atanapi ditunda deui saatos didamel, Soket bakal dianggo pikeun masang bagian na. Because the socket is directly welded to the board, the parts can be arbitrarily disassembled. A ZIF (Zero InserTIon Force) plug allows parts to be inserted and removed easily. The lever next to the socket can hold the parts in place after you insert them.

To connect two PCBS to each other, an edge connector is commonly used. Ramo emas ngandung sababaraha bantalan tambaga bulistir anu saleresna mangrupikeun bagian tina kabel PCB. Biasana, pikeun nyambungkeun, urang lebetkeun ramo emas dina hiji PCB kana Slot anu cocog (biasa disebut slot ékspansi) dina PCB anu sanés. In computers, display cards, sound cards, and similar interface cards are connected to the motherboard by means of a gold finger.

Warna héjo atanapi coklat dina PCB mangrupikeun warna topéng solder. This layer is an insulating shield that protects the copper wire and prevents parts from being welded to the wrong place. Layar sutra anu sanés bakal dicitak dina lapisan résistansi solder. It is usually printed with words and symbols (mostly white) to indicate the position of the parts on the board. Screen printing surface is also known as icon surface

Katerangan).

Dewan Sisi Sisi

Sakumaha anu parantos kami sebatkeun, dina PCB dasar, bagian-bagianna terkonsentrasi dina hiji sisi sareng kabel-kabelna pekat dina sisi anu sanés. Because the wire appears on only one side, we call this TYPE of PCB single-sided. Kusabab panel tunggal ngagaduhan seueur larangan ketat dina desain sirkuit (kusabab ngan ukur hiji sisi, kabelna teu tiasa nyebrang sareng kedah nyandak jalur anu misah), ngan ukur sirkuit awal anu nganggo papan sapertos kitu.

Déwan dua sisi

Papan sirkuit gaduh kabel dina dua sisi. But in order to use both wires, there must be proper electrical connections between the two sides. “Sasak” ieu antara sirkuit disebut liang pituduh (VIA). Liang Pitunjuk nyaéta liang leutik dina PCB dieusian atanapi dilapis ku logam anu tiasa disambungkeun kana kabel dina dua sisi. Because a dual panel has twice the area of a single panel, and because the wiring can be interlaced (it can be wound around to the other side), it is better for more complex circuits than a single panel.

Multi-layer Boards

Dina raraga nambihan daérah anu tiasa kabel, langkung seueur papan kabel dua sisi atanapi dua sisi dianggo. Papan multilayer nganggo sababaraha panel dobel, sareng lapisan insulasi disimpen diantara tiap panel sareng ditempelkeun (dipencet). The number of layers of the board represents several independent wiring layers, usually an even number of layers, including the outermost two layers. Most motherboards are built with four to eight layers, but it is technically possible to build up to 100 layers of PCBS. Kaseueuran komputer super ageung nganggo sababaraha lapisan motherboard, tapi éta teu tiasa dianggo sabab tiasa diganti ku kelompok komputer biasa. Because the layers in a PCB are so tightly integrated, it’s not always easy to see the actual number, but if you look closely at the motherboard, you might be able to.

The guide hole (VIA) we just mentioned, if applied to a double panel, must be through the entire board

But in a multilayer, if you only want to connect some of the lines, the guide holes may waste some of the line space in the other layers. Buried vias and Blind vias avoid this problem because they only penetrate a few layers. Blind holes connect several layers of internal PCBS to surface PCBS without penetrating the entire board. Buried holes are only connected to the internal PCB, so light is not visible from the surface.

In a multilayer PCB, the entire layer is directly connected to the ground wire and the power supply. So we classify the layers as Signal, Power or Ground. If the parts on the PCB require different power supplies, they usually have more than two power and wire layers.

Téknologi bungkusan bagian

Ngaliwatan Téknologi liang

The technique of placing parts on one side of the board and welding the pins to the other side is called “Through Hole Technology (THT)” encapsulation. This part takes up a lot of space and one hole is drilled for each pin. Janten sendi na nyatana nyéépkeun dua rohangan dina dua sisi, sareng sendi solderna rada ageung. Di sisi anu sanésna, bagéan THT langkung saé nyambung sareng PCB tibatan bagéan Surface Mounted Technology (SMT), anu bakal urang carioskeun engké. Sockets like wired sockets and similar interfaces need to be pressure-tolerant, so they are usually THT packages.

Surface Mounted Technology

For Surface Mounted Technology (SMT) parts, the pin is welded on the same side with the parts. This technique does not drill holes in the PCB for each pin.

Bagian perekat permukaan bahkan tiasa dilas dina dua sisi.

SMT ogé ngagaduhan bagian anu langkung alit tibatan THT. Compared to PCB with THT parts, PCB with SMT technology is much denser. SMT package parts are also less expensive than THT’s. So it’s no surprise that most of today’s PCBS are SMT.

Because the solder joints and pins of parts are very small, it is very difficult to weld them manually. However, given that current assembly is fully automated, this problem will only occur when repairing parts.

The design process

Dina desain PCB, saleresna aya léngkah anu panjang pisan pikeun ngalangkungan sateuacan kabel resmi. Ieu mangrupikeun prosés desain utami:

The system specifications

First of all, the system specifications of the electronic equipment should be planned. It covers system functionality, cost constraints, size, operation and so on.

System function block diagram

Léngkah salajengna nyaéta nyiptakeun diagram blok fungsional sistem. Hubungan antara kotak ogé kedah ditandaan.

Divide the system into several PCBS

Dividing the system into several PCBS not only reduces the size, but also gives the system the ability to upgrade and swap parts. The system function block diagram provides the basis for our segmentation. Computers, for example, can be divided into motherboards, display cards, sound cards, floppy disk drives, power supplies, and so on.

Nangtukeun cara bungkusan anu bakal dianggo sareng ukuran unggal PCB

Once the technology and the number of circuits used for each PCB has been determined, the next step is to determine the size of the board. If the design is too large, then packaging technology will have to change, or re-split the action. Kualitas sareng kagancangan diagram sirkuit ogé kedah diperhatoskeun nalika milih téknologi.

Draw schematic circuit diagrams of all PCB’s

The details of the interconnections between the parts should be shown in the sketch. PCB dina sadaya sistem kedah dijelaskeun, sareng kaseueuranana nganggo CAD (Computer Aided Design) ayeuna. Here is an example of a CircuitMakerTM design.

Diagram skéma sirkuit PCB

Preliminary design of simulation operation

To ensure that the designed circuit diagram works, it must first be simulated using computer software. Such software can read blueprints and show how the circuit works in many ways. This is much more efficient than actually making a sample PCB and then measuring it manually.

Place the parts on the PCB

The way parts are placed depends on how they are connected to each other. Aranjeunna kedah disambungkeun kana jalur anu pang éfisiénna. Efficient wiring means the shortest possible wiring and fewer layers (which also reduces the number of guide holes), but we’ll come back to this in actual wiring. Here is what the bus looks like on a PCB. Placement is important in order for each part to have perfect wiring.

Test wiring possibilities with correct operation at high speed

Sababaraha parangkat lunak komputer ayeuna tiasa mariksa naha panempatan masing-masing komponén tiasa leres disambungkeun, atanapi parios naha éta tiasa dianggo leres kalayan gancang. Léngkah ieu disebut nyusun bagian, tapi kami moal jauh teuing kana ieu. Upami aya masalah sareng desain sirkuit, bagian-bagian ogé tiasa diatur deui sateuacan sirkuit diekspor di lapangan.

Ékspor sirkuit dina PCB

The connections in the sketch will now look like wiring in the field. Léngkah ieu biasana otomatis, sanaos perobihan manual biasana diperyogikeun. Below is the wire template for 2 laminates. Garis beureum sareng biru ngagambarkeun lapisan bagian PCB sareng lapisan las masing-masing. The white text and squares represent the markings on the screen printing surface. Titik-titik beureum sareng bunderan ngagambarkeun liang pangeboran sareng panduan. Di belah katuhu jauh urang tiasa ningali ramo emas dina permukaan las PCB. The final composition of this PCB is often referred to as the working Artwork.

Each design must conform to a set of rules, such as minimum reserved gaps between lines, minimum line widths, and other similar practical limitations. Spésifikasi ieu bénten-bénten sesuai sareng kecepatan sirkuit, kakuatan sinyal anu bakal dikirimkeun, sénsitip sirkuit kana konsumsi kakuatan sareng noise, sareng kualitas bahan sareng alat-alat manufaktur. If the strength of the current increases, the thickness of the wire must also increase. In order to reduce PCB costs, while reducing the number of layers, it is also necessary to pay attention to whether these regulations are still met. Upami langkung ti 2 lapisan diperyogikeun, lapisan kakuatan sareng lapisan taneuh biasana dianggo pikeun nyingkahan sinyal transmisi dina lapisan sinyal anu kapangaruhan, sareng tiasa dianggo salaku tameng lapisan sinyal.

Wire after circuit test

In order to be sure that the line is working properly behind the wire, it must pass the final test. Tes ieu ogé mariksa koneksi anu lepat, sareng sadaya konéksi nuturkeun diagram skéma.

Ngadegkeun sareng file

Because there are currently many CAD tools for designing PCBS, manufacturers must have a profile that meets the standards before they can manufacture boards. There are several standard specifications, but the most common is the Gerber Files specification. A set of Gerber files includes a plan of each signal, power and ground layer, a plan of the solder resistance layer and the screen printing surface, and specified files of drilling and displacing.

Electromagnetic compatibility problem

Alat éléktronik anu henteu dirancang pikeun spésifikasi EMC sigana bakal ngaluarkeun tanaga éléktromagnétik sareng ngaganggu perkakas anu caket. EMC maksakeun wates maksimum dina gangguan éléktromagnétik (EMI), médan éléktromagnétik (EMF) sareng gangguan frekuensi radio (RFI). This regulation can ensure the normal operation of the appliance and other nearby appliances. EMC maksakeun wates anu ketat dina jumlah énergi anu tiasa sumebar atanapi dikirimkeun tina hiji alat ka alat anu sanés, sareng didesain pikeun ngirangan karentanan kana EMF éksternal, EMI, RFI, sareng sajabina. In other words, the purpose of this regulation is to prevent electromagnetic energy from entering or emanating from the device. This is a very difficult problem to solve, and is usually solved by using power and grounding layers, or putting PCBS into metal boxes. The power and ground layers protect the signal layer from interference, and the metal box works equally well. We won’t go too far into these issues.

The maximum speed of the circuit depends on EMC compliance. EMI internal, sapertos karugian ayeuna diantara konduktor, ningkat nalika frékuénsi naék. If the current difference between the two is too large, make sure to lengthen the distance between them. This also tells us how to avoid high voltage and minimize the current consumption of the circuit. Laju tunda kabel ogé penting, janten langkung pondok panjangna, langkung saé. Janten PCB alit kalayan kabel anu saé bakal tiasa dianggo langkung saé tibatan PCB ageung.