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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**

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