QFN Soldering - How To Replace QFN / How To Rework QFN 

I want to do a shout out to the good Dr. - I really enjoy your videos and even though I have been soldering for years but not a lot of SMD work. Currently I am bing watching your videos. Just replaced my hot air station as my old el cheapo died during a micro switch replacement. :( . Any who... Thanks for such great videos and hope to see more from you. Be nice to see one on choosing the correct tips as per quality wise. I find using a conical tip the solder tends to run up away from the tip. Its probably my heat setting on my iron.

That last bit will be important for me to remember when designing my boards. Thank you for pointing that out.

In the middle of replacing one in a critical area with much copper plane below. The secret is bottom and top heat of course. Your video is one of the better, if not best, showing QFN with center pad.

Great videos, thanks for sharing your knowledge. Very helpful.

Great video & explanations. QFN has always been a bit of a nightmare for me, and your tips will help ! Thanks for the time you put into this

thanks for all the efforts. Really a great sharing.

i learn heatpad test point at that video. thanks.

what a great and clear video dear friend, indeed, the best!

Got it. Excellent. Thank you

Brilliant channel.

I think it may be good to add heatpad test points out side QFN IC when designing schematic. So you can verify easily if the heatpad conducts well to either ground or Vcc.

Hi there. This has been a very helpful video. Have managed to use the tehniques in this to replace some motor driver and LED drive IC's. I just want to know what flux you are using as the ones that I have don't hold the chips as well as the one that you are using.

Very nicely done clip. If you allow I would like to point out the importance of solder amount on the grond pad. If you apply too much you may create open connections on the outside. Industrial rework procedures typically remove the residual solder and apply new solder paste by e.g. printing the component with an apropriate stencil. To answer also a below question: how to do it with a regular iron - basically this is not a good idea. Simply because the solder joint(s) cannot be reached with the tip. You may refer to the entry level Ersa rework station HR 100 for a controlled heating process or all other rework systems if you need to do it professional. If you need more advice, do not hesitate to contact us.

Thanks sir

Pretty cunning!

Nice video. Thanks for sharing your knowledge. Ive recently bought a re work station. I'm an auto electrician who is keen to get into SMD soldering a lot more. This will be helpful. It looks easy to do but I reckon it's a long learning curve????

Great video, I'm just curious, could you not also probe to another ground solder pad to test? When the chip was off, there was another 2 ground pins (one on the left and the other which you pointed out to the top)

how to test the QFN for continuity to the center pad was the best tip. could you show the side of the Chip so we could see the spot that you tested to?

Two questions: what liquid flux do you use? I’m struggling to replace a QFN16 that has components all around it. Virtually no room to maneuver or place a stencil for solder paste application. Freehand results in too much solder paste. Any suggestions?

Very nice job, I'm looking to replace a QFN on an orange lcd flex, but concerned with how long it took to desoldering this one, but maybe the heat pad on flex will be easier, just don't want to burn the flex. Thanks

Super

Any ideas how to get stuck QFN chip off board easier? Just finally managed to get rid of dead DC stepdown converter in a laptop in QFN-20 package, but it was damn hard. Seems it was soldered with some high melting point ROHS solder plus board has thick copper layer beneath the chip. In end it came off only when I literally broke it in half with soldering iron knife tip from top. Soldering back the new chip with regular 60/40 solder, Amtech NC-559-V2 flux and hot air was not a problem though.

thanks a lot for great information, I have a question and i hope you answer it, is(AWV7BA) chip can be replaced with one of those chips (AWV5QB) (AWV5BB) (AWV5JA)?

Great video & explanations . What type or brand name hot air youre using ? It's Quick 861DW ? :)

What model microscope your use Sir?

Great Vid, especially the slow temp warming before hitting with enough to melt and make connections . I about to try a tiny 1285A reg chip which is only a couple of mm's so pretty small. should i use same tech and temps and time? i worry about overheat insides of chip but have a few spare. Never soldered a chip this small but it makes 3.3 and 5v and about 21 pins and central earth so have to dab solder on that too. Should be fun!!

LOL! That looks very much like a Funcube Dongle Pro Plus... I designed that board! What firmware did you program the new PIC with? If anyone's wondering the reason why there's a lot of space around this chip, it's because originally I laid it out for a 44 pin version of the same device, but due to board dimension constraints I couldn't route enough GPIOs down to the other end of the board despite it being 6 layer. The solution was to use an I2C GPIO expander at that end of the board, which meant I could use the 28 pin PIC instead FWIW there's no practical need to have that PIC's thermal pad soldered for either electrical or thermal reasons. It's what the die is mounted on, but it serves no electrical function. But it's good practice to do solder it anyway. The same isn't true for one of the other QFNs on that side over board, which only exposes its ground connection on the thermal pad, not on any of the pins, so it's essential.

I have hot air and a hot plate, can they be used in combination to help with components like this?

I'm always afraid to over-heat components when I use my hot air station. Apparently ICs like these can take a lot of heat but how high heat can they take and for how long? Are there components that are extra heat sensitive?

Hi, I'm curious, did you just use hot air soldering only? Without hotplate under the PCBs? Thanks before,,

Sir, may I ask you where the 1 pin is on the right side of the dot , or the bottom side of the the dot

I've tried to desolder my old board with qfn chip but i won't come off, any advice? I used 300+ degree celcius with mild airflow for a minute with flux but it still stick to the pcb. Thanks before

I can't seem to avoid getting some solder bridges. And the space between the IC and the surrounding components is too narrow for even my conical tip.

Which camera do u use

Hot to do qfn without hot air? How to do with nornal soldering iron?

What is temperature and air settings

😁👆