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--- mdcpickandplace:qfn [2010/10/19 16:16]
ladyada created
+++ mdcpickandplace:qfn [2016/01/28 18:05]
@@ Line 1: / Line 1: @@
-The coolest parts are now all leadless - great for saving space but a nightmare if you want to place by hand. Even the top skills you use for TQFPs are a challenge against QFNs. Hot air is a must if you want to hand rework these parts. We've found that it is possible to hand-rework/solder with hot air and solder paste but we also like to use our pick and place!
-This tutorial will show how to get QFN/TQFN/LGA/etc leadless parts placed
-====== Lets go! ======
-We'll program the p&p to place an [[http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MMA745xL|MMA7455]] triple axis accelerometer in LGA-14.
-{{:mdcpickandplace:lga14.gif|}}
-{{:mdcpickandplace:lgadim.gif|}}
-===== Outer dimensions =====
-The first things we need to figure out are the **outside dimensions** including **thickness**
-Looking at the dimensional drawing, we see that it is **3mm** by **5mm** and **1mm** thick
-===== Pad size =====
-Next we need to calculate the **pad dimension** this will help the vision system determine what to look for. Note that there is a tiny triangle next to one of the pins, we need to tell the vision to ignore small pads that are just indicators and just use the big pads
-It looks like each rectangular pad is **0.5mm x 0.8mm**
-===== Headline =====

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