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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35
votes
1answer
57k views

How do I identify SMD components? (or how do I identify any component)

How do I identify the markings on an SMT component and match it up with a part number so I can be a good designer and actually look at a datasheet (and read the whole thing)? Or identify a part to ...
42
votes
8answers
5k views

What tools, equipment, and techniques do you use to solder fine-pitch SMT parts?

Possibly many questions have been asked on soldering smd parts, but I haven't found specific answers, Like: Do you use a watchmakers lens or some other type of magnifying glass while soldering these ...
29
votes
3answers
8k views

Should I worry about the risk of tombstoning?

A colleague has (apparently unsuccessfully :-)) tried to convince me of the risk of tombstoning in the following situation: He claims pad 1 for R55 and R59 will lose heat faster during ...
16
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2answers
14k views

The “right” 0805 footprint land pattern

My PCB design software comes with some libraries that include some common components, like chip resistors and capacitors. I have noticed, however, that the footprint land pattern for the 0805 ...
16
votes
8answers
11k views

DIY SMT Reflow: Toaster Oven, Skillet or?

I've read quite a few write ups on converting toaster ovens or skillets for reflowing SMT components. The important parts appeared to be: Attempting to match a reflow profile (temperature pattern to ...
22
votes
8answers
3k views

Pre-programming surface mount ICs

I'm trying to set up a PCB with an atmega168 and no programming header. I intend to use a serial bootloader (there is a ft232 on the board) to reprogram but I am wondering about the best way to ...
40
votes
9answers
15k views

How to hold SMD parts in place while soldering?

I go through this every time I have PCBs I need to populate with SMD parts, and this has become more an issue as pin spacings have gotten tighter, and my hands have become less steady with age. So ...
20
votes
9answers
3k views

Sizing SMD components for Hobbyist Kits

More components are only available in SMD packages. For hobbyist assembly the options are to buy breakout boards or solder SMD. Since components are usually packaged in a couple of SMD package ...
6
votes
3answers
798 views

How to use multiple terminal surface mount chips in amateur project?

As you can probably tell from the question I am a beginner in the embedded world. The extent of my experience is some playing around with C and assembly using the Arduino. I'd like to make the jump to ...
4
votes
3answers
2k 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 ...
27
votes
7answers
28k 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 ...
26
votes
5answers
95k views

Safe temperature for desoldering SMD components w/ hot-air rework gun?

What is a reasonably safe temperature to use for desoldering SMD components using a hot-air rework gun? I have a new-to-me rework station from Xytronic and the documentation clearly assumes you know ...
33
votes
2answers
3k views

Why are SMD LEDs shipped in a sealed bag containing desiccant?

I had a selection of 0805 LEDs in my last Mouser order and was a bit surprised to discover they arrived in heat-sealed (rather than folded and taped with sticker) bags containing a desiccant bag and ...
20
votes
4answers
5k views

Can you stack SMD resistors in parallel to reduce power dissipation per resistor?

I sent my PCB a couple of days ago for fabrication but just realized a terrible error: I need to send 70mA to an IR LED with a 5V supply so I would need a resistor of about 70ohm, which means the ...
7
votes
1answer
659 views

LTC3525 datasheet states that capacitors must be X5R or X7R, not Y5V. Why?

I'm selecting parts to build a 3 to 5V boost DC-DC converter using the LTC3525-5. The board I'm planing to build is based on the typical application shown in page 11 of the aforementioned datasheet, ...
5
votes
2answers
3k views

Standard packages for compact SMT crystals

There is an old and bog standard form factor for SMT crystals - HC49/US. The problem is that HC49/US takes a lot of real estate on the board. It's 12mm long. Another problem with crystals and ...
1
vote
2answers
2k views

How to split Analog and Digital GND planes for a TQFN device

This question is in reference to Mixed signal PCB layout for PSoC. If I am using a microcontroller which has separate analog and digital supply inputs and GNDs, what should do with the grounds? ...
0
votes
1answer
195 views

what tool to use for smd mark code to part number

Is there anyway to find a chip part # based only on the mark codes.it says 633 then below it says MV.from the circuit it seems to be a cap at 2.2uF. any help is appreciated thanks.
10
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5answers
18k views

choosing surface mount resistor/capacitors

So I need design a prototype PCB circuit and need to decide on using what kind of surface mount resistors and capacitors to use. But looking at digikey, there are so many types with many variations in ...
18
votes
13answers
5k views

Recommended PCB houses / Assemblers [closed]

Can anyone recommend a good place to go making PCB's? I'm particularly interested in places that also offer assembly, because this makes SMD parts an option. GoldPhoenix is an option, but not the ...
9
votes
12answers
36k views

What is the best type of magnifier to use for general electronics duties?

I am looking for a magnifier tool for an electronics workbench and was wondering what sort of product would be best. The device must be an all-rounder capable of doing some SMT as well as through ...
14
votes
3answers
4k views

Is it safe to repeat reflow soldering?

I have a board that is partially reflow soldered with a QFN and a couple of 0603 capacitors and resistors. I wanted to test functionality with this stage before I go ahead and place the other ...
6
votes
3answers
40k views

Polarity of unmarked smt electrolytic capacitor

I have a kit with three capacitors, described in the parts list as "10uF 25V SMD 1206" and shown on the circuit diagram as polarised (an open rectangle and a filled one). Seen through the transparent ...
17
votes
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-...
8
votes
1answer
25k views

Advantage or disadvantages of SMD over Through hole design in high frequencies?

I know this is an elementary question. I know that SMD design has the advantage of smaller board size but I dont know which design works better in higher frequencies.
8
votes
4answers
3k views

How close can I place 0603 resistors?

How close can I place two 0603 resistors on a PCB?
5
votes
5answers
6k views

What is the best way to heat sink a chip when soldering it on?

I generally like to solder sockets to my boards, rather than the chip directly, but am now forced to solder the chips directly. I have several DIP and SMD components that this needs to be done with. ...
15
votes
2answers
4k views

How can I use my SMD Arduino to program a separate DIP ATmega328?

I have an arduino with a surface mounted (SMD) microcontroller: I know how to use a DIP arduino as a programmer for a DIP ATmega328. It's easy --you just pop your microcontroller in the holder. ...
8
votes
1answer
2k views

What standard governs the dimensions of SMT chip resistors and capacitors?

I am aware of the JEDEC registered outlines, which define the standard mechanical dimensions and tolerances for a wide variety of solid-state packages. However, these standards do not appear to cover ...
8
votes
3answers
922 views

How to identify this particular SMD component?

It is used on a small board RFID antenna circuit based on the TMS3705: At the first check it seems to be a 0 ohm resistor, but the dimension 4x4mm its strange. Any ideas? L.
6
votes
1answer
751 views

SMD ceramic capacitors producing ticking sound?

I've soldered a couple of SMD capacitors to pads which were not intended to host them. As a result there's a bit of space between the PCB and the capacitors. I have a signal on the capacitors as shown ...
4
votes
1answer
1k views

SMD Removal Process

I'm practicing my SMD soldering skills and done my research on how to remove SMD devices from a PCB motherboard and brought a T8280 PREHEATING STATION and 852D SMD station. I understand you have to ...
2
votes
2answers
642 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 ...
2
votes
3answers
4k views

0805 LED on a 0805 resistor footprint?

The LED in question is described as 0805 dimensionally. However, the footprint in the PDF is different from that described as being suitable for a resistor. For example, the gap between the anode and ...
1
vote
0answers
179 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 ...
1
vote
2answers
512 views

Peak Voltage Ratings of SMD Inductors

Off the shelf SMD Ferrite coils are widely available and popular .The power ratings are adequate for many applications.The manufacturers are clear about the current ratings for saturation and copper ...
0
votes
1answer
72 views

Automate Noise Sensitive Designs of SMD For 95% Sensitivity [closed]

I am thinking of automating my noise sensitive designs of high sensitivity in SMD: maintain 95% signal sensitivity by adjusting the factors (1-3) in the thread What is the best way to layout a PCB ...
-1
votes
1answer
171 views

what component is this? Looks like a cap [duplicate]

It looks to be a cap,and i can measure 2.2uF using my multimeter.From the circuit the cap is in parallel on the positive side of where a ac/dc power source gets plugged in and goes into the Vin on a ...
18
votes
4answers
2k views

Why are power supplies almost always made using through hole components?

Why are power supplies almost always made using through hole components? Every computer PSU I've taken apart uses through hole components, though occasionally (not in all cases) surface mount ...
13
votes
3answers
9k views

How are SMD microcontrollers preloaded with code?

Often when you buy an SMD microcontroller (say AVR) or a PCB with an SMD microcontroller it comes preloaded with whatever program that board uses to run. I was wondering how it is preloaded - I guess ...
9
votes
2answers
1k views

How to deal with LFBGA217 package when building prototype boards by hand

I am involved in a project in which I need to create a few prototype boards that will use the AT91SAM9G20B-CU processor in the LFBGA217_J package. Because this is ...
9
votes
3answers
4k views

Using oblong / rounded surface mounted pads for chip resistors, capacitors and inductors

I'm learning to layout PCBs and lately I came across practice that made me curious. The chip passives' pads are etched with oblong / rounded shape, instead of rectangular shape that is used in all ...
6
votes
2answers
847 views

Size of SMD pads for components with high tolerances

I'm building an Eagle component for an LSM115J. The connectors on this part have fairly large tolerances (1.85-2.21mm width, 0.76-1.52mm length). There is no recommended land pattern. Should I go ...
5
votes
3answers
18k views

TSOT-23-6 vs SOT-23-6

What is the difference between a TSOT-23-6 and a SOT-23-6? I know one is thinner. But in what dimension? I have looked in my PCB editor and they both have the same footprint. Any clarity appreciated!...
3
votes
4answers
3k views

How to connect 2mm surface mount component to 2.54mm breadboard

I have an RF link module with surface mount connectors 2mm apart. This is the datasheet. How would I connect this to a breadboard with 2.54mm spacing?
3
votes
1answer
103 views

Missing pad tCream

I've just finished my first component footprint and then I figured out that there is a pad without tCream, which I guess it is generated automatically. What could be went wrong? By the way, does it ...
3
votes
1answer
191 views

SMD LED: How to calculate optical power (in mW) from luminous intensity (in mcd)?

I chose an LED for my application but I need optical power, in mW. In the data sheet, luminous intensity is shown in mcd but I did not find formulas for calculation although there are graphs, etc. ...
2
votes
4answers
462 views

How many times can an IC be desoldered and resoldered?

For a long time now, I had a fear, that when you solder a SMD IC to a PCB, that you won't be able to desolder and resolder it again without destroying it. Recently, I did just that, but it didnt ...
2
votes
2answers
14k views

How to identify SMD devices from the codes on top of the component?

I have a PCB and I am trying to identify a couple of the ICs and other SMD devices that are on there but can't find anything on or offline that tells me what the package codings mean. I have a couple ...
1
vote
3answers
621 views

choosing the right fuse for a PCB

I am experimenting with making a PCB and have created some short circuits when wiring everything up which have fried one of the traces. i was wondering whether it would be a good idea to put a fuse in ...