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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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
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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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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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172 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
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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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57 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
14k 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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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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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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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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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, ...
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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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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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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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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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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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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) ...
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1answer
349 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 ...
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1answer
875 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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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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2answers
80 views

reflow oven issues with RO4003 PCB

Im trying to reflow some RF pcbs in a legit reflow oven. The PCBs material is "Rogers RO4003 305 Um" and 3 layer. (Its a very thin pcb) If temperature is high enough to reflow the paste, the pcb ...
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Can I use SMD components or do I have to stick to through hole?

I work in a company which develops devices that need to withstand harsh environmental conditions, shocks, radiations, vibrations and whatever. Really, too many to count. In one of those devices is a ...
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1answer
127 views

Help identifying SMD on USB Circuit (Wacom Intuos 5 - PTH850)

My Wacom Intuos 5 - PTH850 Tablet have one the following SMDs (the lower one, USB Data -) cracked. Could you help me identifying which component is? I know each component bridges USB data + with ...
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216 views

Self Resonant Frequency VS Package Size for capacitor

In general belief, smaller capacitors have better charactristic(more capacitive behaviour) in high frequency than bulky capacitors. On contrary in one of my RF project (8.5GHz - 9.5GHz) when checking ...
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1answer
483 views

How to properly connect SMD component to inner layer

I have a four layer board. The stack is divided as follows: Layer 1: Signal Layer 2: GND Layer 3: Power Layer 4: Signal I have SMD components such as an SMD fuse,...
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206 views

PCB Power Pad destroyed for TPS51125. Fixable?

While trying to fix a laptop, I was de-soldering a TPS51125. I added a bit too much solder to the power pad while wicking so I had the "smart" idea to use a solder pump to remove it... but the pad ...
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2answers
146 views

What wire to buy to extend the legs of SMD components?

I am attaching some neopixels to an art project. Rather than buy the breadboard style neopixel which is 4x as expensive, I am buying the SMD style and just soldering legs on. This worked well for a ...
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1answer
531 views

Choosing an SMD Resettable fuse for a 2.5 Ampere USB charger port

So I have googled for more than an hour, trying to find the specific answer for this, and maybe Im searching all wrong, but here comes my question. I have a USB-hub combined with one fast charging ...
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3answers
132 views

Makeshift SMT Station. Any suggestions? [closed]

I am trying to do some surface mount soldering for my project and have hit a few snags. My hot air gun works perfectly fine for most of the PCBs I am making but one type in particular is problematic....
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1answer
719 views

smd orientation for pick and place

I am trying to confirm the right orientation for all the packages I am using in Eagle before sending for pick and place assembly. After reading a bit, I understand that there is no standard from one ...
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1answer
129 views

Component identfication for IC marked C50 23XH

The letters on the chip are: C50 23XH What is the producer of this chip? What is this IC?
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156 views

How to deal with unused components in pick-and-place file?

I intend to send a board to a PCB manufacturer and I am wondering how to mark unused components in the pick and place file. I'm using EAGLE and I saw that it includes all components in the file, but I ...
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3answers
1k views

The best way to attach a heatsink to a SMD component?

There's a SoC I want to throw a heatsink on. What's the best way to do this for maximum heat transfer and longevity? I know of thermal pads, thermal adhesive, and thermal paste -- but when it comes ...
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2answers
8k views

Hot air rework temperature to avoid solder melt on opposite end

When removing/replacing chips. Is it safer to use little to no air flow but higher temp heat or lower heat with more airflow? My hot air station is a model 852d+ with a max temp setting of 500c and ...
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2answers
213 views

Are IOT wireless network protocol right for high throughput point to point communication?

I am trying to build a "professional" 2 way point to point radio system (like this) to control a RC 1/10 scale car (like this ) using UART, the challenge I am currently facing is finding the right ...
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55 views

Is there a popular footprint for right angle SMT LEDs?

I am designing a PCB with SMT LEDs at the edges. The LEDs have to be right-angle type (ie. shine sideways). With regular LEDs I can use an 0805 or 0603 footprint and tell the assembly house to place ...
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3answers
208 views

Can I get away with that poorly designed board?

I am designing a board but space is not a luxury that I have at the moment, can I get away with that design or I must use a SMD resonator?
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1answer
310 views

Tolerance on SMD Aluminum Electrolytic Capacitors

I'm searching for some polarized surface mount device capacitors on lcsc.com and notice that they only have tolerances of \$20\%\$ tolerance devices in their catalog for this type of SMD device ...
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105 views

Advice on connecting a Li-Po battery to SMD terminal?

I would like to connect a Li-Po battery pack with female PH connector such as the one shown below to a PCB which will use SMD devices. I have also provided the circuit diagram below and highlighted ...
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3answers
13k views

Best Way to Solder/Desolder Surface Mount Components

I recently got my hands on some old motherboards/PCB's, and even though I know reusing parts from old PCB's is not as good as using new parts, I was wondering what the best way is to solder/Desolder ...
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1answer
268 views

Component identification (SMD)

Help me identify this component: test results identify it as a diode. I believe the manufacturer is Vishay, but I can't find anything when I search for it. There is a label placed on the component: "....
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7k views

What does WFQFN stand for?

I saw this as a package type for an attiny microcontroller in the digikey catalog. I'm pretty sure that "QFN" stands for Quad Flat No leads. However, I'm not sure what prefixed "WF" means. Is there a ...
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2answers
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MLCC - Can I use high voltage rated caps for very low voltage scenarios?

Is there any important reason why I can`t use high voltage mulilayer ceramic capacitors for low voltage scenarios? For example 50V or 100V rated MLCCs for 3.3V DC applications? I have bad eyes, and ...
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What ceramic capacitor is this?

I'm almost sure this is a ceramic capacitor, but I have trouble finding its characteristics. The first picture is the top side, the second the bottom side. The first shows: 120G (or 12OG) and an F. ...
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1answer
375 views

Identifying SMD Resistor with a code that contains a colon

What are the blue components seemingly labeled "69:1" in the attached image? There is reason to believe that they are resistors, but of what value? I thought perhaps the ":" is a "00" written on top ...
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Faulty Voltage regulator?

Cant identify what is this ...SMD The only thing i can understand is that is Motorola. Any help appreciated.
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4answers
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Can I use thermal paste instead of solder for a SMD heat sink?

I have some high-power (~5W) SMD LEDs that I will be running for extended periods of time. I would like to use a PCB mill to make breakout boards for these chips for easy prototyping. Ideally I would ...
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1answer
3k views

Soldering smallest SMD components such as 0402 with Microscope?

I need to use as small components as possible but I need to do everything by hand. My plan is to use OSH Park for the production of the board. The answers did not focus on whether they used microscope ...
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3answers
313 views

Soldering SMD by soldering iron

I need to solder header connector dedicated for SMT on my control PCB. My problem is that I have only standard soldering iron and I don't have a rework station. Please, can somebody tell me whether it ...

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