Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [qfn]

For questions related to the QFN (quad-flat no-leads) component package.

QFN (quad-flat no-leads) devices have a rectangular package with contact pads along each edge that do not extend out past the edge of the package. Advantages include a smaller physical size and reduced lead inductance at the cost of them being more difficult to hand-solder and rework. The Wikipedia page Quad Flat No-leads package has more information and shows a typical QFN package:

QFN package

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If there are different packages for the same component, which one you should consider?

I am designing a small PCB for mass production, and I am trying to keep costs low. One of the components is available in several different packages: 24QFN, 32QFN and LP (TSSOP 24 Pin). There is a significant difference in price and size. So, what…
Javier Loureiro
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In production, is there a significant difference between QFN or TQFP components other than space?

When producing a run of PCBs, does it matter if I choose QFN or TQFP components? Say, I want to have 1000 boards manufactured with an Atmel AVR that is available in QFN or TQFP packages. The QFN package is of course smaller, but I have enough space…
Niels Heidenreich
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Do QFNs really need that thermal pad?

Often a chip will be available in several different packages. Sometimes QFN which has a thermal pad, and TQFP which has no thermal pad. The justification for the thermal pad is that it helps conduct heat away from the IC. If this were the case, then…
Rocketmagnet
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How do I solder this tiny QFN chip

I am not very experienced with soldering. I have a basic soldering iron with a new tip, and a third hand. Last time I tried soldering wires to a ble chip that looked like this, I ruined two chips in the process and gave up. Those were not cheap. Now…
rosewater
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Why do I have shorts/bridges on QFN packages on PCBA during assembly? Stencil Printing problem

I am trying to do a home assembly of PCB but I have issues after reflow soldering. Especially I have bridges/shorts on the pins of QFN packages. I have assembled multiple boards other joins are okay but each time I have randomly bridged pins on…
D_Dog
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How bad is it to places vias under a QFN thermal pad?

I'm working on a PCB which has to be very small. There is a QFN IC which has a big thermal pad, although it doesn't really need to dissipate that much heat. So to save some space, I came up with the idea of reducing the footprint of the thermal pad…
Venemo
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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 standard reference that would have this…
Eraticus
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Potential pitfalls/caveats for developing a stencil for solder reflow

I'm developing a project that requires ICs that are in a QFN package, some have a slug on the bottom of the IC. Since these are QFNs, I'm not interested in hand soldering these; so I'm leaning toward using the toaster oven method to solder the…
Nick Williams
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How to solder QFN-16 with a central pad component to proto-board?

I have a QFN16 breadboard adapter and an ASXL335 chip, which I'd like to solder to it: However, the accelerometer chip has a central pad, while board does not. This causes an annoying problem of soldering paste gathering under the pad and pushing…
Roman Susi
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What's going wrong with my solder paste / mask?

A short question this - I've got a board with a QFN-32 0.4mm pitch footprint, I ordered this stencil, and a tube of this solder paste, and the result is in the picture below. Now, I'm new to this, but I've done some homework about process and indeed…
John U
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Small DFN chips come out twisted from the oven

This is a 2 x 2 mm chip with 12 no lead contact points. Half of the time I get it out of the reflow oven, it's twisted like in the image below. I am using a stencil in order to lay the paste down and then tweezers for placing the little chips. There…
kellogs
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24-pad, 0.5mm pitch: better to use QFN or BGA?

For a certain TI component, I'm choosing between these two packages, both of which are 24-pad and 0.5mm pitch: QFN: http://www.ti.com/lit/ml/mpqf167b/mpqf167b.pdf (4 x 4 mm) BGA: http://www.ti.com/lit/ml/mpbg520/mpbg520.pdf (3 x 3 mm) Some…
AlcubierreDrive
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Purpose of pins on side edge of QFN package

I have a QFN part that contains exposed pins on the side (in addition to the bottom). It looks like the quantity and spacing of the side pins are perfectly matched with the bottom pins, except there are a couple little smaller pins in the corner.…
user2913869
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What are QFN sockets for?

I would like to use a QFN chip but soldering it is difficult as the required tools are unavailable. After searching online, I found that there are sockets available that provide pins for those chips, such as this one . However I saw on the title…
M.abououf
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QFN Standoff (Solder Joint) Height

When designing a QFN footprint, I've read from (reputation limited, only 2) sources... http://www.freescale.com/files/analog/doc/app_note/AN1902.pdf http://www.atmel.com/images/doc8583.pdf ...that the QFN should sit approximately 50-75um (2-3 mil)…
Anton
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