Questions tagged [surface-mount]

Surface-Mount Technology (SMT) refers to the way components are mounted on a PCB: SMDs (Surface-Mounted Devices) have pins or contacts which lay on top of the PCB's pads, without the need for holes in the PCB.

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1answer
96 views

How do I identify the SMD component marked as !3S 4?

I have a SOT-23 SMD component marked \$\underset{\bullet}{\vert}3\bar{\textrm{S}}\;\bar{4}\$ as shown in the following images I managed to find out that \$\textrm{3S}\$ stands for MMBT5551 NPN ...
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How to remove/desolder very minute smd chips safely? [duplicate]

This is the component I'm trying to remove: BU48xx voltage detector VSOF package (attached pic)
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2answers
394 views

Is there any reason to prefer one MLCC manufacturer over another?

I'm specifying some SMD chip capacitors for the first time and I note there are several manufacturers out there: muRata, Yageo, Vishay, AVX, Kemet in particular, perhaps others. Is there any good ...
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93 views

Need help decoding part number for SOT23-5 chip

I have a circuit board that has come out of a smart plug-in lamp dimmer/switch module. I would like to find the part number of a small SOT23-5 integrated circuit chip that is on this board. The SMT ...
3
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1answer
135 views

What is the name of this part?

I thought it was called a "jog dial" but I can't any parts by that name. There are five pins on the back and one on each side. What is it called and how can I find a replacement? It is similar to ...
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1answer
232 views

Removed all ceramic SMD capacitors without markings on them from the board… what to do? [closed]

When I told a buddy that I am taking electronics courses and learning to manufacture simple homemade PCB boards, he found me a client with an interesting offer: To reverse engineer a small PIC ...
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7answers
32k views

vias directly on SMD pads?

I was looking at an example board schematic provided by TI and I noticed something rather curious: vias were placed directly on SMD pads. Is this a normal/acceptable practice to follow? Or is it ...
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4answers
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Probably overheated black color SMD pads

Can you give me an advice what to do with probably overheated SMD soldering pads on the board? The photo is of a computer bus card, where there are 4 SMD 0603 positions labeled R1 - R4. They are used ...
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3answers
161 views

Help identifying an SMD component [duplicate]

I need help identifying an SMD component it is a small(1 mm X 1.5 mm) black part with an "O" written on top if it. I think it is a Schottky diode for reverse polarity protection ?. (Source, first ...
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1answer
48 views

SMD Stencil Material Choice

We are planning to purchase a stencil for our LED boards. This will be my first stencil purchase so I don't have much idea about a good or bad one. The inquiries I received typically suggest two ...
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1answer
92 views

What is this SMD part?

I’m trying to repair a powered recliner touch sensor, and I’ve isolated the part that I think is the problem. The issue is, I don’t know what it is! In the first image, you can see that it has three ...
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1answer
140 views

Identify SOT-563 device with top code 49K

Please help me to identify this SOT-563 device with top code 49K
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2answers
242 views

Robustness of surface mounting daughterboards

I am using a "Teensy" development board in a project and would like to attach it to my main PCB including the surface mount pads for the usb data lines. Are there any reasons I shouldn't just design ...
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1answer
193 views

RF limiter for -20dbm

I am working on a receiver in which I would like to limit the RF power at input to -10dBm to -20dBm, the receiver is working for frequency 1GHz. I Have checked pin diode limiters and shottkey diode ...
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44 views

SMD Detector Microswitch Replacement

One of my son's toys stopped working and I decided to jump in to see what was causing the problem. I found that a number of the smaller detector microswitches had their tabs broken off. Therefore ...
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1answer
435 views

Why did KiCad merge my pins into one open blob in the solder mask gerber?

I designed a PCB with an IC that has a pitch of 0.5. The footprint solder mask looks like this: However, the gerber came out with one blob that looks like this: Why did it do that? Can I stop it? ...
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1answer
470 views

Which SMD component is labeled “20 3C”?

Please help me to identify the SMD marked as 20 3C, which is used in a cable TV set top box tuner section for amplifying the RF input. It's operating on 5V DC. ...
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2answers
127 views

I don't know the name of the following 4-pin connector

I want to replace an SMD connector on the following PCB, but I do not know how to search for it, in order to buy it. I have attached a photo from the male connector, it might help. Can you name it?
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3answers
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Help on ID for SMD component (probably diode)

I recently smoked a DC motor control board and need help identifying the wounded component. before picture (H2 and sideways 3) and here it is, wounded It looks to me like a resistor SMD; but, of ...
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2answers
81 views

IC has different pinouts on different packages? [closed]

I am going to use the HT16C21 LCD driver to drive my LCD. Looking at the datasheet (in the "Pin Assignment" section), I noticed that the IC comes in 4 different packages, each with varying numbers of ...
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1answer
45 views

Surface mount package size 201-1

Does anyone know what a 201-1 package size is, and how it might differ from a 'normal' 0201? I found it in a MacBook schematic. Thanks in advance for your help.
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2answers
145 views

Help to identify SMD part

Can anyone help to give any clues about identifying this part? It is from a Chinese guitar pedal and appears to be at the beginning of the input chain, so I would suspect perhaps some kind of op amp, ...
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3answers
3k views

Looking for capacitance and voltage rating - How to read electrolytic SMD capacitor labels

I need to replace an SMD capacitor on a board. The printing on it says F1 560 2.5z I have googled intensely but have been unable to find information on how to read such a codes. I need to find out ...
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4answers
664 views

Beyond what is recommended by fabricators, how far should traces be from SMD pads?

Having followed a fabricator's DRC (this case being OSHPark), this distance between an SMD pad and a trace is considered acceptable (see attached images). However, I wanted to inquire about what the ...
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2answers
304 views

Accidental solder in vias

I am doing some assembly on a PCB which has a variety of SMD components. I accidentally got a little crazy with some paste on a large GND pad for an ESP32 component. I went to place the component on ...
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2answers
935 views

Help identifying SMD component

I’m trying to replicate something I got a few years ago for practical use and I found every component except for this one. It says WL BD on the package and measures 2.58x1.53mm (LxW) and around 1.3mm ...
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1answer
789 views

Routing large RF trace to small SMD pad

I am designing an RF board in Altium where due to the dielectric selected and its thickness, the trace width for a 50 ohm characteristic impedance is thicker than some of the SMD component pads. What ...
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2answers
126 views

What's the name of smd buttons build of a simple thin metal sheet which flex when pressed?

As the topic title, I tried to find them but cannot get any informations about. They are a sort of SMD tact switch made only by a very thin curved metal sheet. When you press they flex and make ...
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1answer
280 views

Eagle - Custom pad shape for SMT inductor

I'm trying to make the following footprint in Eagle for an SMT inductor: I understood how to make D-shape pads and similar, but this is driving me nuts: my idea was to enclose a pad into a polygon ...
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1answer
1k views

Calculating SMD resistor temperature rise

I am interested in knowing the actual power dissipation of an SMD resistor at a 70C ambient temperature. I am looking at a 10kOhm 2512 1Watt resitor RMCF2512JT10K0. from the electrical specifications ...
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1answer
2k views

Identify unknown SMD component code A6530 72130

I have a TTL to RS485 driver board and I am try identify one of the manufacturer part number from the board. Can anyone identify the SMD Code and manufacturer part number of the following device? ...
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6answers
3k views

SMT solder reflow temperature profile

I have read many website and forums about DIY reflow ovens for SMT soldering. I have also seen many solder profiles as specified by the solder manufacturers, component manufacturers, and other self-...
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4answers
168 views

Attaching wires to a SMT footprint

I have a pre-made motor controller which I want to re-purpose for a hobby project by pulling the MCU off and attaching to a custom control circuit (with a more powerful MCU, current sensors, etc). The ...
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2answers
1k views

Troubleshooting defective LED bulbs

I bought 10 Thomas Watt LED bulbs and 8 are dead in less than a year (each last about 2-3 months). Soometimes a couple of days before they stop working, they flicker when I switch them on or after ...
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0answers
56 views

How to increase SMD codes readability

is there any substance to increase the SMD codes readability when the component is very small or has a poor print on it? Some years ago I saw a video where they suggest to use alchol, but I tried ...
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3answers
13k views

Difference between 1206, 0805 and 0603 SMD resistor

What is the difference between a 1206, 0805 and a 0603 SMD resistor, as far I know they all have a resistance of 10.7K? I going to need one for my little 5v DC buck converter.
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7answers
2k views

How can the ACS712 pin handle 20 A?

I am searching for some current measuring ICs and found the ACS712, but what I can't figure out is how the seemingly small pins can handle the 20 A current since the trace width calculators say that I ...
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2answers
200 views

SMD tactile switch with 4 pins extension

I have a problem, I have a row of 4 horizontal SMD tactile switches on a circuit board I want to mount them externally so I desoldered them and put 4 wires to each corner of each switch and resoldered ...
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1answer
77 views

I have an SMD switch how can I find the part number?

I have an SMD switch but I don't know its part number. I searched suppliers sites like Digikey and ... but I couldn't find it. Is there any other way to find the part Number? The size is 6*6*5(...
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0answers
66 views

0402 SMD resistance shortcut [duplicate]

I am wiring a small plastic model with 11 yellow 3V 0402 LEDs. I used the resistance calculator to find I need as many 56ohm resisters attached to each LED in parallel to keep them running properly, ...
4
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2answers
134 views

Should I design a high-power switched mode power supply with surface mount components?

I'm designing a SMPS for a fairly high-power application (2kW, 50A). In looking at the available components, sometimes almost the exact same components are available in surface-mount and through hole ...
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1answer
52 views

How do i find Current Consumed by Circuit designed on Surface mount PCB without damaging PCB? [closed]

I have a circuit designed on PCB, and components (resistors, capacitors, diodes, Microcontrollers etc.) are all surface mount. I want to find the total current consumed by this circuit. I have traced ...
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2answers
524 views

What is the purpose of this extra PCB pad?

I am looking to use this crystal in an upcoming design and I am a little bit confused by the datasheet. The datasheet is available here: CMR200T Datasheet This is the image in question: Question: ...
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2answers
1k views

What is the effect that makes components on a circuit board move into place?

I am going to apologize ahead of time if this is a really simple question. I started learning to solder during my internship but I had no EE knowledge prior. When I was working with surface mount ...
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1answer
1k views

Identify SMD component labelled W16 95

I'm trying to find out what element is the one that is on the PCB that is labeled as QD2. On the body it has mark W16 and 95, but I couldn't find anywhere on internet what this element is. This is ...
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3answers
141 views

Electrical isolation problems when routing between pads of SMT resistors/caps

According to answers to this previous question, routing traces between the pads of SMD caps/resistors, as shown in the picture, is not dangerous as long as trace to pad clearances are obeyed and the ...
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1answer
60 views

How would I determine the ideal capacitor for a specific application

I am attempting to replace a Surface Mounted Multilayer Ceramic Capacitor in an Amiga A4000 which is described in a BOM as: Capacitor, SM, MLC, NPO, 100pF (1206) ...
8
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1answer
339 views

I need help to identify this old SMD device

I'm working on a circuit and I can't find information on this component (see picture). This hybrid circuit is part of an old industrial PSU. It is a PFC circuit based on UC3854 but I don't know if the ...
5
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1answer
855 views

Do SMD resistors have to be reflowed black side up, or is black side down okay?

I reflow my own boards in a toaster oven. When I drop my resistors off the paper tape, I always flip them over to black side up before I place them. Should I bother if it doesn't really matter?
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3answers
180 views

0402 SMD resistance problems

I've trying make a very simple 3 LED circuit with a red, blue and green LED. I know my 3v battery will take the path of least resistance and only flow through the red, so I've added resisters to the ...

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