The LimeSDR Mini Open Source, USB, Programmable Software-Defined Radio

September 26, 2017 by Tim Youngblood

The popular open source LimeSDR USB stick programmable software-defined radio is about to get a smaller, cheaper little brother.

The popular open source LimeSDR USB stick programmable software-defined radio is about to get a smaller, cheaper little brother.

The Original LimeSDR and The World's First FPRF

Lime Microsystems began making waves with the LMS6002D, which was dubbed the world's first field-programmable RF chip (FPRF). FPRF technology is still in its infancy but it got a lot of designers excited because it allows one chip to be programmed for several different wireless protocols. This means that you wouldn't need to make changes to your hardware design if you want to sell your products in new areas that use different protocols.

Last year, Lime Microsystems successfully crowd-funded the mass production of their open source LimeSDR platform. They more than doubled their funding goal and kickstarted an open source community. The LimeSDR has even been nicknamed "The Arduino of software-defined radio." LimeSDR is popular among professional designers, makers, and researchers and students testing new wireless protocols.

Since it has a USB stick at the end of the board and a GUI, users can get started with it easily. Users are also able to download programs uploaded to Ubuntu Snap, which is used as a kind of app store. This brought the required expertise for using and programming software-defined radio. With LimeSDR, Lime Microsystems is on their way to fulfilling their mission statement:

"Our goal is to democratize wireless innovation"

The LimeSDR Mini

So what's different about the new LimeSDR Mini?

Obviously, it's smaller and less expensive (LimeSDR is $300 whereas the LimeSDR Mini is only $100), but it still shares the same RF transceiver (LSM7002M) as its big brother. It uses a different FPGA (10M16SAU169C8G) and has only two channels instead of four. These two channels use SMA connectors to make connecting antennas easier. The original LimeSDR had four micro U.FL connectors, which do not have convenient threads to screw on antennas.

The LimeSDR Mini still uses the same dev tools and community as the original, so the Mini gives up two channels and some memory, but retains most of the same functionality for a third of the price. As of publication, the LimeSDR Mini has exceeded their funding goal by over $23,000. You can back the project on Crowd Supply until just before the end of October.

LimeSDR Mini Hardware Specifications

  • RF transceiverLime Microsystems LMS7002M
    • Bandwidth up to 120MHz  
    • Frequency ranging from 100kHz to 3.8GHz 
  • FPGA: Altera MAX 10 (10M16SAU169C8G)
    • 169-pin FBGA package
    • 16 K Les
    • 549 KB M9K memory
    • 2,368 KB user flash memory
    • 4 x fractional phase locked loops (PLLs)
    • 45 x 18x18-bit multipliers
    • 130 x general purpose input/output (GPIO)
    • Single supply voltage
    • Flash feature
    • FPGA configuration via JTAG
  • EEPROM memory: 2 x 128 KB for RF transceiver MCU firmware and data
  • Flash memory: 1 x 4 MB flash memory for data
  • General user inputs/outputs:
    • 2 x dual color (red + green) LED
    • 8 x FPGA GPIO pinheader (3.3 V)
  • Connectivity:
    • USB 3.0 Type-A (FTDI FT601 controller)
    • 2 x coaxial RF (SMA) connectors (each can be switched between high and low frequency bands)
    • U.FL connector for external clock source
    • FPGA GPIO headers
    • FPGA JTAG connector
  • Clock system:
    • 30.72 MHz onboard VCTCXO
    • Possibility to tune VCTCXO with onboard DAC
    • External clock input via U.FL connector
    • Board dimensions: 69 mm x 31.4 mm



A block diagram of the LimeSDR Mini. Courtesy of Crowd Supply.

Resources for Software-Defined Radio and LimeSDR

  • F
    fjean September 29, 2017

    That’s an awesome device here considering the price and form factor !

    It would have been nice to remember the RF capabilities of the transceiver in the hardware specification. That’s just the most important stuff here. Otherwise i can just get an RTL SDR for 10$ that has the same form factor !

    So max RF spec are bandwidth up to 120MHz with the frequency ranging from 100kHz to 3.8GHz (This is for the transceiver so it will depend on the electronic design as well)

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  • P
    pyroartist October 24, 2017

    Could this device be used for a radar if the transmitter output was amplified? Can it transmit and recieve pulses?
    Or continuous modulated signals such as FM or AM?

    Like. Reply