The modern radio amateur now has access to not only ordinary components with leads, but also such small, dark parts that you can’t understand what’s written on them. They are called "SMD". In Russian this means "surface mount components". Their main advantage is that they allow the industry to assemble boards using robots that quickly place SMD components in their places on the printed circuit boards, and then mass bake them to produce assembled printed circuit boards. The human share remains with those operations that the robot cannot perform. Not yet.
The use of chip components in amateur radio practice is also possible, even necessary, as it allows you to reduce the weight, size and cost of the finished product. Moreover, you practically won’t have to drill.
For those who first encountered SMD components, confusion is natural. How to understand their diversity: where is the resistor, and where is the capacitor or transistor, what sizes do they come in, what types of SMD parts are there? You will find answers to all these questions below. Read it, it will come in handy!
Quite conventionally, all surface-mount components can be divided into groups according to the number of pins and housing size:
| pins/size | Very very small | Very small | Little ones | Average |
| 2 outputs | SOD962 (DSN0603-2) , WLCSP2*, SOD882 (DFN1106-2) , SOD882D (DFN1106D-2) , SOD523, SOD1608 (DFN1608D-2) | SOD323, SOD328 | SOD123F, SOD123W | SOD128 |
| 3 pins | SOT883B (DFN1006B-3) , SOT883, SOT663, SOT416 | SOT323, SOT1061 (DFN2020-3) | SOT23 | SOT89, DPAK (TO-252), D2PAK (TO-263), D3PAK (TO-268) |
| 4-5 pins | WLCSP4*, SOT1194, WLCSP5*, SOT665 | SOT353 | SOT143B, SOT753 | SOT223, POWER-SO8 |
| 6-8 pins | SOT1202, SOT891, SOT886, SOT666, WLCSP6* | SOT363, SOT1220 (DFN2020MD-6), SOT1118 (DFN2020-6) | SOT457, SOT505 | SOT873-1 (DFN3333-8), SOT96 |
| > 8 pins | WLCSP9*, SOT1157 (DFN17-12-8) , SOT983 (DFN1714U-8) | WLCSP16*, SOT1178 (DFN2110-9) , WLCSP24* | SOT1176 (DFN2510A-10) , SOT1158 (DFN2512-12) , SOT1156 (DFN2521-12) | SOT552, SOT617 (DFN5050-32), SOT510 |
Of course, not all packages are listed in the table, since the real industry produces components in new packages faster than the standardization bodies can keep up with them.
The housings of SMD components can be either with or without leads. If there are no leads, then there are contact pads or small balls of solder (BGA) on the case. Also, depending on the manufacturer, parts may differ in markings and dimensions. For example, capacitors may vary in height.
Most SMD component housings are designed for installation using special equipment that radio amateurs do not have and are unlikely to ever have. This is due to the technology of soldering such components. Of course, with a certain persistence and fanaticism, you can solder at home.
Types of SMD housings by name
| Name | Decoding | number of pins |
| SOT | small outline transistor | 3 |
| SOD | small outline diode | 2 |
| SOIC | small outline integrated circuit | >4, in two lines on the sides |
| TSOP | thin outline package (thin SOIC) | >4, in two lines on the sides |
| SSOP | seated SOIC | >4, in two lines on the sides |
| TSSOP | thin seated SOIC | >4, in two lines on the sides |
| QSOP | Quarter size SOIC | >4, in two lines on the sides |
| VSOP | Even smaller QSOPs | >4, in two lines on the sides |
| PLCC | IC in a plastic case with leads bent to form a letter-shaped case J | >4, in four lines on the sides |
| CLCC | IC in a ceramic package with leads bent to form a letter-shaped package J | >4, in four lines on the sides |
| QFP | square flat case | >4, in four lines on the sides |
| LQFP | low profile QFP | >4, in four lines on the sides |
| PQFP | plastic QFP | >4, in four lines on the sides |
| CQFP | ceramic QFP | >4, in four lines on the sides |
| TQFP | thinner than QFP | >4, in four lines on the sides |
| PQFN | power QFP without leads with a pad for a radiator | >4, in four lines on the sides |
| BGA | Ball grid array. Array of balls instead of pins | pin array |
| LFBGA | low profile FBGA | pin array |
| C.G.A. | housing with input and output terminals made of refractory solder | pin array |
| CCGA | CGA in ceramic case | pin array |
| μBGA | micro BGA | pin array |
| FCBGA | Flip-chip ball grid array. Man array of balls on a substrate to which a crystal with a heat sink is soldered | pin array |
| LLP | leadless housing |
From this whole zoo of chip components that can be used for amateur purposes: chip resistors, chip capacitors, chip inductors, chip diodes and transistors, LEDs, zener diodes, some microcircuits in SOIC packages. Capacitors usually look like simple parallelipipeds or small barrels. The barrels are electrolytic, and the parallelepipeds will most likely be tantalum or ceramic capacitors.
Chip components of the same denomination may have different dimensions. The dimensions of an SMD component are determined by its “standard size”. For example, chip resistors have standard sizes from “0201” to “2512”. These four digits encode the width and length of the chip resistor in inches. In the tables below you can see the standard sizes in millimeters.
| Rectangular chip resistors and ceramic capacitors | |||||
| Standard size | L, mm (inch) | W, mm (inch) | H, mm (inch) | A, mm | W |
| 0201 | 0.6 (0.02) | 0.3 (0.01) | 0.23 (0.01) | 0.13 | 1/20 |
| 0402 | 1.0 (0.04) | 0.5 (0.01) | 0.35 (0.014) | 0.25 | 1/16 |
| 0603 | 1.6 (0.06) | 0.8 (0.03) | 0.45 (0.018) | 0.3 | 1/10 |
| 0805 | 2.0 (0.08) | 1.2 (0.05) | 0.4 (0.018) | 0.4 | 1/8 |
| 1206 | 3.2 (0.12) | 1.6 (0.06) | 0.5 (0.022) | 0.5 | 1/4 |
| 1210 | 5.0 (0.12) | 2.5 (0.10) | 0.55 (0.022) | 0.5 | 1/2 |
| 1218 | 5.0 (0.12) | 2.5 (0.18) | 0.55 (0.022) | 0.5 | 1 |
| 2010 | 5.0 (0.20) | 2.5 (0.10) | 0.55 (0.024) | 0.5 | 3/4 |
| 2512 | 6.35 (0.25) | 3.2 (0.12) | 0.55 (0.024) | 0.5 | 1 |
| Cylindrical chip resistors and diodes | |||||
| Standard size | Ø, mm (inch) | L, mm (inch) | W | ||
| 0102 | 1.1 (0.01) | 2.2 (0.02) | 1/4 | ||
| 0204 | 1.4 (0.02) | 3.6 (0.04) | 1/2 | ||
| 0207 | 2.2 (0.02) | 5.8 (0.07) | 1 | ||
Ceramic chip capacitors are the same size as chip resistors, but tantalum chip capacitors have their own size system:
| Tantalum capacitors | |||||
| Standard size | L, mm (inch) | W, mm (inch) | T, mm (inch) | B, mm | A, mm |
| A | 3.2 (0.126) | 1.6 (0.063) | 1.6 (0.063) | 1.2 | 0.8 |
| B | 3.5 (0.138) | 2.8 (0.110) | 1.9 (0.075) | 2.2 | 0.8 |
| C | 6.0 (0.236) | 3.2 (0.126) | 2.5 (0.098) | 2.2 | 1.3 |
| D | 7.3 (0.287) | 4.3 (0.170) | 2.8 (0.110) | 2.4 | 1.3 |
| E | 7.3 (0.287) | 4.3 (0.170) | 4.0 (0.158) | 2.4 | 1.2 |
Inductors are found in many types of housings, but the housings are subject to the same size law. This makes automatic installation easier. And it makes it easier for us, radio amateurs, to navigate.
All kinds of coils, chokes and transformers are called “winding products”. Usually we wind them ourselves, but sometimes you can buy ready-made products. Moreover, if SMD options are required, which come with many bonuses: magnetic shielding of the housing, compactness, closed or open housing, high quality factor, electromagnetic shielding, wide range of operating temperatures.
It is better to select the required coil according to catalogs and the required standard size. Standard sizes, as for chip resistors, are specified using a four-number code (0805). In this case, “08” indicates the length, and “05” the width in inches. The actual size of such an SMD component will be 0.08x0.05 inches.
Diodes can be either in cylindrical cases or in cases in the form of small parallelipipeds. Cylindrical diode packages are most often represented by MiniMELF (SOD80 / DO213AA / LL34) or MELF (DO213AB / LL41) packages. Their standard sizes are set in the same way as for coils, resistors, and capacitors.
| Diodes, Zener diodes, capacitors, resistors | |||||
| Type of shell | L* (mm) | D* (mm) | F* (mm) | S* (mm) | Note |
| DO-213AA (SOD80) | 3.5 | 1.65 | 048 | 0.03 | JEDEC |
| DO-213AB (MELF) | 5.0 | 2.52 | 0.48 | 0.03 | JEDEC |
| DO-213AC | 3.45 | 1.4 | 0.42 | - | JEDEC |
| ERD03LL | 1.6 | 1.0 | 0.2 | 0.05 | PANASONIC |
| ER021L | 2.0 | 1.25 | 0.3 | 0.07 | PANASONIC |
| ERSM | 5.9 | 2.2 | 0.6 | 0.15 | PANASONIC, GOST R1-11 |
| MELF | 5.0 | 2.5 | 0.5 | 0.1 | CENTS |
| SOD80 (miniMELF) | 3.5 | 1.6 | 0.3 | 0.075 | PHILIPS |
| SOD80C | 3.6 | 1.52 | 0.3 | 0.075 | PHILIPS |
| SOD87 | 3.5 | 2.05 | 0.3 | 0.075 | PHILIPS |
Surface mount transistors can also be of low, medium and high power. They also have matching housings. Transistor cases can be divided into two groups: SOT, DPAK.
I would like to draw your attention to the fact that such packages may also contain assemblies of several components, not just transistors. For example, diode assemblies.
Sometimes it seems to me that the marking of modern electronic components has turned into a whole science, similar to history or archeology, since in order to figure out which component is installed on the board, sometimes you have to conduct a whole analysis of the elements surrounding it. In this regard, the Soviet output components, on which the denomination and model were written in text, were simply a dream for an amateur, since there was no need to rummage through piles of reference books to figure out what these parts were.
The reason lies in the automation of the assembly process. SMD components are installed by robots, in which special reels are installed (similar to the reels with magnetic tapes) in which chip components are located. The robot doesn’t care what’s in the bag or whether the parts are marked. Humans need labeling.
At home, chip components can only be soldered up to a certain size; size 0805 is considered more or less comfortable for manual installation. Smaller components are soldered using a stove. At the same time, for high-quality soldering at home, a whole range of measures should be observed.
Hello friends and readers of the "RADIO SCHEMES" site, we continue to get acquainted with modern ones. Today's review is an overview of SMD transistors, which you have probably already seen in various modern electronic devices.
Transistors in SMD packages are very convenient, especially where every millimeter of the board is important. Imagine how a mobile phone (the board of which is entirely made of SMD parts) would change if it used regular DIP pins.
Above is a photo of an SMD transistor against the background of a regular one, in TO 92.
This is a photo of various SMD transistors, on the right is the usual one in TO92. As a rule, the pinout of all such transistors is the same - this is also a huge plus.
Name of various packages, DIP and SMD. The photo can be enlarged.
You can see how planar transistors are made below.
Planar transistors, like conventional transistors, have many types, composite (Darlington), field-effect, bipolar and IGBT (insulated gate bipolar transistors).
Please note that on boards and circuits transistors are marked “Q” and “VT” (this should be the case, although some manufacturers are disdainful of this), why am I writing this? Often, the manufacturer can cram everything he wants into the same case - from a diode to a linear voltage regulator (78xx), even various sensors. There are also internal factory markings, for example parts from Epcos. It is very difficult to find a datasheet for such details, and sometimes it is not available on the Internet at all.
Soldering such transistors is not difficult, it especially speeds up and makes it easier the process of soldering various SMD parts - a microscope, tweezers (simply irreplaceable things), various fluxes and soldering fats with BGA paste. First, we tin the contact pads of our transistor and the board (do not overheat).
Then we position our transistor, I do this with tweezers.
Solder any of the legs. We release the tweezers and position our part as evenly as possible, for a great look, so to speak :)
Solder the remaining “legs” of the radio element.
And now our transistor is firmly and well soldered to the board. In the following articles, I will write about this in more detail (fluxes, tweezers, soldering, etc.). As for the designations and pinouts of different types of transistors, there are several very useful links on the forum. Wrote the article BIOS.
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