Exposed Vias in BGA Pads
Open or exposed vias are never put in BGA pads. However, it is permitted to place them between the pads if a complete solder mask dam is inserted between the pad and the via. You can also instruct your assembly house to fill and plate the vias, but only use metal on the PGA pad.
You have more flexibility when using other types of components. But you have to make some choices and follow accepted guidelines. Let use consider a large part, such as a voltage regulator, where the vendor advises to connect vias to the thermal pad in the ground plane, or on the back side of the board in the thermal area. For this application, it is similar to the way a QFN is treated; read our recommendations regarding that type of package.
In applications where you have a lot of room, which gives you flexibility, if you have exposed vias, you may experience that solder is pulled to the reverse side of the board. This is okay if the vias are very small. However, this is not a wise practice.
Your choices come with pluses and minuses. For example, some manufacturing engineers recommend that a via should never be filled or capped because it would inhibit the transfer of heat. Conversely, power component vendors say you should not use an un-manufacturable design to meet product design requirements. The best choice is to cap the via with solder mask, but make it as small as possible (i.e., 100-125 microns bigger than the via). You should section off the paste stencil layer in segments. Remember, problems may occur if solder paste is placed on top of an exposed via or masked via.
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: [email protected]||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 !