If you´re facing a decision which diode to use in your device or searching for a replacement, then this article is dedicated right for you.
Reliable diodes are often one of the fundamental pillars of a proper operation of devices. Many designers choose a suitable type so to say “by an eye” , by experience. So it can easily happen, that there will be used a uselessly overrated diode (occupying more PCB space) or in a worse case – an insufficiently rated diode, which will work in a given device on the border of its possibilities.
Diodes in general feature one good property – they´re relatively easily replaceable by a similar type from another producer. KAs SOS electronic is the authorized distributor of company Diotec, we´re able to offer you a suitable type for virtually any device, or a replacement for almost any diode from other producers. Diotec as a producer specialized mainly on diodes, offers a wide portfolio of diodes with axial leads, in SMT packages, including power types like power sod-123, Power-SMD, D-PAK (TO252AA) and D2PAK (TO263AB), super-fast with low losses but even rectifying bridges and many other types.
Schottky diodes naturally provide lower losses thanks to a lower forward voltage, that´s why their usage is mainly in place in applications with relatively higher currents. In general it´s also valid, that a small SMT package can significantly eliminate the radiation of EMI in switch-mode power supplies (thanks to a minimal parasitic inductance), what can be one of factors, whether a given device will meet EMI regulations or not.
On the internet, it´s possible to find various „cross-reference-lists“, but for a given application, usually only some selected parameters are important. That´s why we better recommend to choose according to concrete parameters. A help at selection will provide you the case cross reference and the list of most commonly used 1A diodes. For a practical usage, it´s good to be familiar with hints for soldering and assembly, minimum solder pads sizes as well as basic facts about basic facts about thermal stresses of diodes.
Also available to download is the example of usage of Diotec diodes in Set Top Boxes and in LED driving. It is worth to mention, that also several fakes of Diotec diodes appeared on the market.
Do you need diodes? – Diotec has them - [Link]
GSM, DCS, PCS, UMTS, 434/868 MHz, GPS, TETRA and many other signals are no problem for small ceramic antennas from company 2J.
Among products from company 2J, which can be found in our stable stock offer, we recently incorporated miniature ceramic SMT antennas enabling to create miniature closed devices without any external antennas, connectors, cables, …
● 2JE03 – 5-band SMT antenna for GSM850, GSM900, DCS, PCS and UMTS (1710-2170 MHz) bands. With dimensions of only 24×5.5×4.4mm, it represents a miniature solution for a wide spectrum of applications.
● 2JE05 – extremely small (9x3x1,2mm) SMT antenna intended for free bands 434 MHz, 868 MHz and 915 MHz. The antenna can be easily matched for a given frequency band by means of a few passive LC components (matching circuit). 2JE05 features a relatively very good standing waves ratio (VSWR) max 2.0:1 in the whole range.
Detailed specification of these antennas can be found in the 2JE03 and 2JE05 datasheets. A comprendious overview will provide you the 2J catalogue as well as catalogue of internal (embedded) antennas. Upon order, we´re able to provide you any antenna from the 2J portfolio. In case of interest, please contact us at email@example.com.
Miniature SMT antennas 2J are able to cover several bands - [Link]
SMD solder paste stencils are used to accurately “print” a thin layer of solder paste onto a PCB on which the components are placed before reflow soldering. The “printing” is done in a method similar to screen printing, where the solder paste is squeegeed through a 4 mil thick, stainless steel stencil onto the PCB.
This is all well and good, but commercial stencils are expensive, and are massive overkill for prototype boards. Here is a method for producing a “good-enough” stencil using aluminium sheet via a method similar to PCB production via the UV photosensitive film method.
Home-made solder paste stencil - [Link]
Our friend Vasilis posted a video story of a successful SMD reflow process… at his home, amazing!
Powered by the Low Budget Manual Pick and Place : http://vpapanik.blogspot.gr/2012/11/low-budget-manual-pick-place.html
SMD reflow at home - [Link]
Action video of the Low Budget Manual Pick and Place Originally posted in : http://vpapanik.blogspot.gr/2012/11/low-budget-manual-pick-place.html
Low Budget Manual Pick and Place (HD) - [Link]
Literally endless long bands of a linear light can be produced with LEDs of the Duris E3 and E5 series. A wide-angle beam and a very uniform light distribution make these LEDs very easily applicable.
This is exactly the case of Duris E3 and Duris E5 LEDs. Thanks to their compact SMT packages, they can be freely used on PCBs of virtually any shapes. Small dimensions of both LEDs enable tight placing of LEDs next to each other. OSRAM Duris E3 and Duris E5 LEDs feature a very homogenous radiation pattern in a wide angle (120°) and a high efficiency of up to 110lm/W. The result is a perfectly homogenous light without visible dots. That´s why they´re perfectly suitable for a construction of replacements of classic fluorescent lamps (CCFL) (T5 a T8) and bulbs. Duris E3 and E5 have very similar optical specification, the main difference is in the maximum current of 30mA/E3 versus 180mA/E5.
It is good to realize, that a maximum current of LED has nothing in common with efficiency, i.e. even low-power LEDs feature a high efficiency (lm/W). That´s why approximately the same-efficient light source can be created by 1 OSRAM OSLON Square LED, but even by for example 50 pcs Duris E3 or 8 pcs Duris E5. An advantage of high-power LEDs is an easy achievement of a high luminous flux from a small area (spot lights) and an easy application of optics. On the other hand, less powerful LEDs are usually more easily applicable, no secondary optics is necessary and often even no additional heatsink is necessary because the power is dispersed on a bigger area and already the PCB itself is often able to lead away and dissipate a generated heat. That´s why the usage of Duris E3 and E5 is very simple and virtually immediately after soldering LED to a PCB we gain a working source of a homogenous light. .
A light without an end with OSRAM Duris E3 and E5 LEDs - [Link]
Super Simple SMT: Stencil8 – [via]
Over the years, I’ve soldered a fair number of boards. I’ve also seen how professional factories produce their boards. This is my technique for doing it myself, and I hope it works as well for you as it does for me. Note: the files needed to make the fixture, custom pcb setup, and stencil are on Github – Stencil8. This whole project is OSHW.
Super Simple SMT: Stencil8 - [Link]
BF245, a JFET transistor produced for many decades by several companies, has joined the list of discontinued components. However an equivalent replacement exists in an SMT package and its name is BF545.
BF245 in a TO-92 package has been one of the first transistors, which were mass-used. That’s why it’s no wonder, that the BF 245 is nowadays familiar to every experienced technician. As a transistor with a very high input resistance (tens of MOhm) and a relativlely low noise, it’s gained a global popularity and served to many beginning technicians at an assembly of their first radio-receivers. There are many other FET transistors on the market nowadays, thus the usage of BF245 is substantially smaller. Moreover, a majority of electronics is produced with SMT components, what probably was one of more reasons why all main producers have discontinued the BF245.
However, BF245 is still an interesting transistor, that’s why it will be henceforward available in a SOT23 SMT package as the BF545. It is available in 3 groups A, B, C – sorted according to IDSS at VGS=0. Directly from our stock are available BF545A, BF545B and BF545C from company NXP (originally Philips). Detailed information can be found in the BF545 datasheet, as well as in the RF Manual document.
BF245 – the legend is leaving, the successor comes - [Link]
SMT components are still more used even in small production batches. That´s why in our portfolio, many components can be found in both versions – THT (through-hole technology) and also SMT.
As the praxis has shown, both Technologies have their stable place in the production of electronics. This is also confirmed by a known fact, that the highest density of components on a single-sided PCB can be reached by a combination of SMT and THT components, when the THT components on the rear side also act as „PCB tracks“.
To many components, which we have in both SMT and THT version, we incorporated a well-known favorite diode 1N4148 in an SMT sod123 package – 1N4148W. It is a universal switching (small signal) diode with a small PN junction capacitancy, thus suitable even for fast circuits. Small leakage current ensures a minimum influence of surrounding circuitry, that´s why the 1N4148 is often used also as a protective diode for protection of digital circuits inputs. Next time, when you´ll design a device with a 1N4148, try to consider, whether an SMT version wouldn´t suit better to you – 1N4148W, LL4148 (miniMelf), TS4148 or other versions.
Favorite diodes 1N4148 -THT but also SMT - [Link]
Here is Texas Instrument’s application note on Ball Grid Array IC packages - [via]
Leaders in the consumer electronics industry will be determined by their ability to deliver increasingly miniaturized products at lower costs. The Ball Grid Array (BGA) package achieves these objectives by providing increased functionality for the same package size while being compatible with existing Surface Mount Technology (SMT) infrastructure.
Ball grid array explained - [Link]