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Assembled and functional

 

We got a call earlier this week letting us know the assembled boards were ready to be picked up!

The build quality looked amazing, and from a first inspection it seems as though most components were placed correctly. The orientation of the LEDs was harder to determine due to their smaller size but those checked out as well.

stack

 

With high density interconnects, visual inspecting BGAs and fine pitch QFNs is not possible so we had X-ray the boards.

LMS6002D X-Ray, this is a 112DQFN package

Some of the thermal relief VIAs wound up getting plugged, however it is evident that none of the solder leaked outside of the boundaries of the thermal relief pad. The darker spots that can be seen between the two rows of the DQFN are 0201 capacitors and resistors underneath the LMS part.

FX3 X-Ray (0.8mm pitch 121-pin BGA)

We were a little worried about the manufacturability of our boards when the PCB house told us we were getting close to pushing their capabilities, however the X-Ray shows pretty clearly that all of the VIAs underneath the FX3 are well defined and symmetric.

 

After making sure there were no shorts by checking resistance between the different power supplies and ground, it was time to power up the board. Luckily no sparks came flying out. After checking that all 7 key power domains were at the right voltage, the board was plugged in to a running laptop. The Cypress development tools quickly detected the Cypress USBBootloader that boots from ROM when the SPI flash does not contain a valid image. Within its first few minutes of operation, the Bulk Loopback benchmark utility was running and showing round-trip throughput of 250MB/s. Theoretically, the FX3 should be able to do nearly 400MB/s but Window’s XHCI driver has some catching up to do when compared to Linux 3.5.

 

Cypress’s development tools talking to the BladeRF

 

 

Lastly, builds of this run usually tend to leave a lot of left over components, here’s a few pics of the mess we’ve created:

Left over cyclone 4s

 

Left over component bags full of tapes, reels, and trays

 

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The boards have arrived

 

This is another exciting week, we finally got a call from the PCB manufacturing house letting us know the boards are ready. Although we’re planning on using the same contract manufacturers for assembling all of the boards, we wanted to take a few of the extra boards home and examine their build quality.

As of the moment, there appear to be no shorts between any of the ground or power planes, and most signal traces don’t seem to have shorts with any of their neighbors! This kind of inspection is necessary because flying probes may not catch all these kinds of manufacturing errors.

 

boards