Tuesday, September 20, 2005


Here is a picture of the FPGA_USB board after soldering most of the components:

Yet to be soldered is the FPGA, USB connector, and connection headers.

I soldered all of the components by hand. Soldering the 128 pin 0.5mm pitch Cypress FX2 microcontroller was much easier than I thought it would be. I need a little more magnification than the Bausch and Lomb 3.5x eye loupe has. I also have a Luxo magnifying fluorescent light that I use when soldering the other components. I am thinking about getting a 7x Bausch and Lomb loupe that clips onto glasses for soldering the 0.5mm pitch stuff. There is a seller on Ebay that sells stereo microscopes on a boom arm for about $260 that would be nice.

Basically I spread a lot of flux on the pads for the FX2 chip, tacked down the pins in the corners to keep the chip in place, and then proceeded to solder the pins using a drag technique with a conical tip on the Weller EC2001 soldering station. I then inspected each pin by lightly pushing sideways with a fine pointed tool to check for any pins that where not soldered down. I found 4 out of 128 and a light touch up with the soldering iron fixed those.

The other components were a piece of cake using the magnified swing-arm fluorescent light. I used 0.015" SN63PB37 Kester solder, SP-44 Kester Paste Flux, and a Weller ETU 0.01" x 0.4mm flat tip on the soldering station.

Next I will solder on the USB connector, apply power, connect to the PC, and see if the FX2 enumerates.

1 comment:

Anonymous said...

hi phil,

i was wondering wht do you think of solder reflowing (instead of hand soldering) for smaller pitch smt parts. (like the s3 xcs400 pq208)