Working with QFNs and QFPs

The QFN is a leadless, quad flat pack, integrated circuit package. It is very small and is more convenient to use than a micro BGA. 

Micro BGAs that have a pitch of 0.5mm or smaller are both costly and less convenient to use because they have double rows of pins. With this type of package layout, escape routing can utilize plated or plugged vias, which makes the board layout more difficult, hence, more expensive to manufacture.

QFNs are about the same size as micro BGAs but have exposed pins that are around the perimeter of the package. Hence, they do not require escape routing.

It is critical to remember that even though QFPs and QFNs use the same letters (i.e. Q and F) one cannot be replaced with the other. Now, sometimes, PCBs use both types of component types.

Both QFPs and QFNs are used because the Atmega32U4 used in the Leonardo at times cannot be purchased due to limited supply availability. Hence, both types give you more flexibility that won’t need PCB design changes at a later date. You may want to consider this if the PCB has enough room for a QFP or you are concerned about part availability. If you are, here are some things to think about:

1. Ensure all the pin-outs have a one-to-one correspondence. At times there will be differences or extra pins.
2. To avoid noise problems make sure your PCB has enough space. In general, bypass capacitors should be placed very close to supply pins. For the most part, this isn’t a problem for QFNs. But, in rare instances, it will.
3. Verify that the unsoldered pads will not pose problems. Harsh environments can affect these pads to cause problems. If this is a problem, you should apply a conformal coat to the board.

Keywords:

SMT Reflow Oven, Lead free Reflow Oven, Reflow Oven Manufacturer, LED reflow oven, PCB Reflow Oven, Nitrogen Reflow Oven, Dual Rail Reflow Oven, China Reflow Oven, wave soldering machine, Dual Rail Wave Soldering Machine, Nitrogen Wave Soldering Machine, Wave Soldering Machine Manufacturer.

Flason Electronic Co.,ltd provide a full SMT assembly line solutions, including SMT Reflow Oven,  Wave Soldering Machine,  Pick and Place Machine,  SMT Stencil Printer,  SMT AOI SPI Machine,  SMT Reflow Oven,  SMT Peripheral Equipment,  SMT Assembly line,  SMT Spare Parts  etc any kind SMT machines you may need, please contact us for more information: wechat whatsapp:+8613691605420, Skype: flasonsmt, Email: sales@flason-smt.com
FAQ
1) This is the first time I use this kind of machine, is it easy to operate?
There is English manual or guide video that show you how to use machine.
If you still have any question, please contact us by e-mail / skype/ phone /trademanager online service.
2) If machine have any problem after I receive it, how can I do ?
Free parts send to you in machine warranty period.
If the part is less than 0.5KG, we pay the postage.
If it exceeds 0.5KG, you need to pay the postage.
3) MOQ ?
1 set machine, mixed order is also welcomed.
4) How can I buy this machine from you? ( Very easy and flexible !)
A. Consult us about this product on line or by e-mail.
B. Negotiate and confirm the final price , shipping , payment methods and other terms.
C. Send you the proforma invoice and confirm your order.
D. Make the payment according to the method put on proforma invoice.
E. We prepare for your order in terms of the proforma invoice after confirming your full payment.
And 100% quality check before shipping.
F.Send your order by air or by sea.
5)Why choose us ?
A. Gold supplier on Alibaba !
B. Trade assurance to US$54,000 !
C. Best price & Best shipping & Best service !