Questions tagged [qfn]

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

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165 views

How do i solder qfn package using soldering iron?

I don't have any soldering station but I need to solder the qfn package chip so how I solder it using a normal soldering iron.
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2answers
120 views

LGA parts and hot air soldering

Does the solder pattern on these huge pads indicate what might be going on ? The parts would not work about 80% - 90% of the time. I am trying to follow the ramp_up-soak-reflow-ramp_down curve to ...
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42 views

PCB design - paste coverage calculation for exposed pad (TL;DR version?)

I have created a Web tool for creating solder mask and paste mask for exposed pad: https://jsfiddle.net/d1wang/5t6urzwo/ The idea is get around limitation of DipTrace and help automate footprint ...
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2answers
228 views

Soldering 0.4mm pitch QFN 48 chip

I have this QFN 48 chip which has the following design : As it can be observed, the pitch is 0.4mm. It seems like the conventional QFN adapters won't fit because the conventional ones has the pitch ...
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2answers
135 views

Removing QFN Lead Frame From PCB

We have some PCBs that were designed to drive high-power ultrasound transducers. There was an issue with the boards early on that resulted in several of them blowing diodes. I have since fixed the ...
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1answer
146 views

How to Solder TQFN packages that are on both sides of the PCB

Due to a careless selection of components (and you could say also bad layout) I ended up having a PCB with surface mount pads on both sides and on the same x,y coordinates. I have already used my ...
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1answer
302 views

How can I align chips on PCB?

I am searching for a method/device for aligning chips with pins/pads underneath, like QFN, LGA, BGA and others. I've been searching the Internet, but I could find anything except expensive (several k€)...
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0answers
68 views

Identify Quad Flat package

I looked for days trying to find datasheet to this component. I concluded that this is a Quad Flat No-lead. But trying to search the marking code gets me nowhere. I did however find couple websites ...
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2answers
441 views

QFN20 package sizes

I'm trying to use the capacitative touch chip CPT112S for a project. It comes in QFN20 3x3 package size but the pad layout is different to what I expected and so doesn't fit the DIP adapters I have. I'...
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1answer
299 views

Do all ATmega32u4 QFN ground pads need to be connected?

A QFN chip I'm working with (atmega32u4) has multiple pads connected to ground, see the picture. Is it really necessary to connect all these pads? Could I say omit one or is it really bad practice? ...
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1answer
148 views

QFN32 exposed pad stencil

I made a pcb with a QFN32 with exposed pad but I feel like I've made a mistake on the stencil, in the exposed pad area. I managed to solder it and the chip (CC1310) is programmed successfully but I'm ...
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1answer
524 views

VQFN Footprint for PCB Design?

I am currently working with TI's TPS61235. I need to put this IC onto a custom PCB for a project, but I cannot find any libraries for PCB designing software for this VQFN-9 layout. Is there anywhere ...
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1answer
336 views

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 ...
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1answer
497 views

Questions about Solder Mask Expansion Rules and Passive design in Altium

I am working on my first Systems project as a student and I am learning how to integrate chips as I go along in Altium. I recently came across this question in which you provided a rule for ...
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1answer
72 views

Footprint of L6226Q

The L6226Q H bridge is using a QFN32 package. Actually in the datasheet, it has this layout: and it was noted that the pins 2 to 8 are connected to the die PAD and the die PAD must be connected to ...
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1answer
176 views

Removing QFN vias

I've used the footprint wizard to generate QFN package, the result: My question is, if it's OK to remove the vias since I want to put some components to save same room?
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3answers
2k views

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, ...
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3answers
1k views

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 ...
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2answers
5k views

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 ...
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3answers
2k views

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 ...
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2answers
472 views

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 ...
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4answers
6k views

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 ...
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2answers
5k 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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1answer
874 views

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 ...
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4answers
584 views

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 ...
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2answers
2k views

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/...
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2answers
2k views

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 ...