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PicoZed SDR power-only carrier

liuf_stanford

We're developing an application using the PicoZed SDR which needs only power inputs from the carrier - no IO (ethernet, USB, HDMI, etc...) required. Since we don't want to re-invent the wheel, are there any such designs which already implement this functionality? If not, are there any good resources out there which might help us design our own carrier?

 

I know Avnet no longer sells PicoZed SDR units, but I'm posting here since replies on the EngineerZone forum are slow (and mostly useless).

 

Thanks!

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    I'm not aware of a power only carrier... the most minimal carrier available that I know of is the breakout carrier: http://zedboard.org/product/picozed-sdr-breakout-carrier .  But, if you really just need power, you could install a power connector by soldering wires directly to the PicoZed SDR module (be sure to strain relief the wire, looping it through a mounting hole or something, so it doesn't rip the pads from the board if it gets pulled on).  It wouldn't take much to throw together a simple PCB to provide just +5V to one of the connectors either (if you can solder one of the mating surface mount connectors).

     

    Also... IIRC, it needs an updated power sequencer load to run from only +5V.  Otherwise, the module won't boot while it waits for the rest of the voltages.

     

    Pat

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    Thanks, Pat. We'll look toward developing our own board based off of the breakout carrier schematic. I'll also be sure to update the SOM's power sequencer.

     

    If we plan to use only 5V, is there any handshaking necessary between the carrier and SOM (from the schematic it seems that this is not the case but I wanted to double-check just to be sure)? I also see from the user guide that there are several 5V VIN pins and numerous GND pins - are they all tied together on the SOM or does the carrier need to provide connectors for all of them?

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    I'm just going by memory (I designed my custom carrier about a year ago), but I'm pretty sure you're correct that there's no need to do any sort of "handshake" between the two.  There are a few status and control pins, but they're pulled up where necessary, so ignoring them just works (with the sequencer update).

     

    I don't know the answer about the VIN and GND pins... I would assume that they're all tied together on the board, since the schematics for the module don't say otherwise.  The connectors are rated for 800mA per pin, so you'll need to watch your total current if you don't connect all of them... but it sounds like you're looking for a pretty minimal application, so you probably won't have high power requirements.  JX2 has 5 VIN pins vs. 4 VIN pins on JX1... so if you really don't care about any of the other pins, I'd go with JX2 for the extra power pin.  Otherwise, JX1 has the JTAG pins, DONE flag, etc.

     

    Pat

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    This has been incredibly helpful - thank you Pat.

     

    I'll try to remember to a brief update once we've design and tested the board.

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    Hate to open up an old thread, but ran into one other issue we'd like to resolve before proceeding.
     
    After a long delay, our custom power-only carrier is nearly complete. However, we are a bit unsure about power input requirements to the SDR SOM. We'd like to power the SDR using a single Li-Ion battery (3.7V), but don't know if we can flash the onboard power sequencer to accept such a low voltage. Even if we could, would we risk potentially damaging any components?
     
    Thanks!
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    It probably wouldn't damage anything by running it from a single Li-Ion battery, but it probably won't work very well.  I believe all regulators on the module are step-down, so as soon as the voltage drops a bit, your regulators (particularly the 3.3V ones) won't be regulating anymore.

     

    The manual says it can take between 4.5V and 5.5V, so I'd personally run a step-up converter from the single Li-Ion to create +5V, and run from that.

     

    Pat

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    Quick update: we created a power-only carrier board (very simple 2-layer PCB) and it seems to be working. SOM boots and is able to transmit a signal at the frequency we have specified. Thanks for your help, Pat.