LimeSDR USB Power Supply Rating and Recommended Adapters

Based on the “External power supply damaged board?” topic (External power supply damaged board?), it looks like a bunch of people have burned their boards by using external (non-USB) power supplies even though the voltages seem to be compatibility with the specifications (which currently say “External 6V - 12V DC power supply” at https://wiki.myriadrf.org/LimeSDR-USB_User_Guide). So, I have the following questions:

a) What is the minimum required amperage?

b) Can you recommend a power supply (like you do with the other accessories, under “Additional Components”, here: https://wiki.myriadrf.org/LimeSDR-USB)?

c) Would heavy transmit/receive power typically result in exceeding what a good USB power source can supply, or should a good USB power source always be sufficient (where an alternative external power source would only be necessary with a weak USB power source, which I’m assuming would be bus-powered rather than hub-powered)?

d) In light of so many people damaging their [fairly expensive] LimeSDR USB boards by simply trying to provide sufficient power to them within the boundaries of the limited specifications, can you improve the specifications to be more, er, specific, such as providing:

  • a minimum amperage
  • a specific voltage
  • recommendations for one or more specific adapters

There seems to be an abundance of <=5V barrel adapters (with too few being >=6V as required) of that specific size and a couple of 12V adapters (where 12V has already been mentioned as burning a board) and it’s been nontrivial to find a power-supply-reinforced USB accessory to try and boost the power to the LimeSDR.

Thanks. It seems like a power-supply is necessary but that a lot of people have damaged their boards by using one. These answers could really assuage peoples’ fears (mine included).

Dustin

1 Like

I have a good quality USB3 hub that supplies 3 amps. The LimeSDR-USB has only drawn 750 ma. I fried the power switching chip in mine with a 12VDC wall wart.
Worksussut fine TX/RX on the USB3 hub.
Works just fine from my Dell G3 laptop.

Ed

Hi Dustin,

I am agree with AA7QQ if possible find a good USB3 hub with good USB3 cable its a risky business use “what ever I have” PSU conected to LimeSDR.
with my limeSDR I use 12v 3A PSU but I “old school” capacitance multiplier" so I get about 10v output and I use heatsink for regulator chip, FPGA and LMS7002 plus a generous fan.

Anton

Ah. Thanks for sharing that measurement.

+1

I put used heat conducting epoxy to add heat sinks to every chip I could fit them to. Be sure not to cover up the reset switch for the FX3 chip.

Ed