LimeSDR XTRX is high-performance software-defined radio (SDR) board in a compact Mini PCIe form factor. With an AMD Artix™ 7 XC7A50T-2CPG236I FPGA and a Lime Microsystems LMS7002M RF transceiver at its core, LimeSDR XTRX is a perfect platform for developing logic-intensive digital and RF designs.

LimeSDR XTRX (top)

LimeSDR XTRX is a suitable building block for MIMO configurations from 2Tx2R to 32Tx32R. It can be used in conjunction with digital processors (ASICs, GPPs and GPUs) of varying speed, power dissipation, and cost to fit any air interface, whether narrowband or broadband. The board is designed for the following key feataures:

• Frequency and Bandwidth: The heart of the board is the Lime transceiver RFIC (LMS7002), covering frequencies up to 3.8 GHz with a bandwidth of over 100 MHz.
• Baseband Interface: A significant level of digital circuitry resides within the LMS7002 and accompanying FPGA for the implementation of key physical layer radio functions, including filtering, decimation, interpolation, and flexible interfaces such as PCIe and SerDes.

LimeSDR XTRX (bottom)

Open Source

LimeSDR XTRX is based on the Fairwaves XTRX Rev 5, with many many refinements and updates. We will review all the changes in a future update. One of the biggest changes is that we have open sourced the design files and documentation, so you can start exploring LimeSDR XTRX for yourself. Altium project files and their outputs, including BOM, schematics, and layout, are available in the LimeSDR XTRX GitHub repository. Project files that can be run on the free (as in beer) version of Xilinx Vivado v2022.1 (64-bit) are available in the LimeSDR XTRX FPGA gateware GitHub repository. Source files in both of these repositories are published under the Solderpad Hardware License v2.1.

Support & Documentation

As a full-fledged member of the LimeSDR family, LimeSDR XTRX benefit from the same support as other LimeSDR products, which means any existing LimeSDR-family application can work on LimeSDR XTRX once it is rebuilt with the latest verions of any library that supports LimeSDR. In addition, the legacy gateware and driver for the original XTRX is still available to aid in the transition to LimeSDR XTRX, though the legacy versions will not be actively maintained.

Resources to get started with LimeSDR XTRX include:

• MyriadRF documentation
• MyriadRF forum
• Altium project source files
• Vivado FPGA gateware source files
• Lime Suite driver
• GNU Radio gr-limesdr plugin
• Fairwaves legacy gateware and driver (for transition purposes only - not actively maintained)

Block Diagram

Features & Specifications

• RF transceiver: Lime Microsystems LMS7002M
  • Configuration: MIMO (2xTX, 2xRX)
  • Frequency range: 30 MHz – 3.8 GHz
  • Bandwidth: 120 MHz
  • Sample depth: 12 bit
  • Sample rate: 120 MSPS SISO / 90 MSPS MIMO
  • Transmit power: max 10 dBm (depending on frequency)
• FPGA: AMD Artix™ 7 XC7A50T-2CPG236I
  • 236-pin CSBGA package (10mm x 10mm, 0.5mm)
  • 52160 LUTs logic capacity
  • 2700 Kb Embedded Memory
  • 600 Kb distributed RAM
  • 120 x 18x18-bit multipliers
  • 5 x PLL
  • 4 x DLL
  • 106 x IO
  • FPGA configuration via JTAG
• USB 2.0 controller: Microchip USB3333E-GL
• EEPROM Memory:
  • 128 Kb EEPROM for LMS MCU firmware (optional)
  • 128 Kb EEPROM for FPGA data (optional)
• FLASH Memory: 256 Mb Flash memory for FPGA configuration
• Temperature sensor: TMP1075NDRLR
• General user inputs/outputs:
  • 2 x green LEDs
  • 4 x GPIO 3.3V in GPIO connector
  • 1 x GPIO in baseband connectors
• Connectors:
  • USB 2.0 (Micro-B) socket
  • Coaxial RF (U.FL female) connectors
  • FPGA GPIO 8-pin FPC connector
  • FPGA JTAG connector (unpopulated)
  • Mini PCIe edge connector
  • RF baseband 15-pin FPC connectors
• Clock system:
  • 26.00 MHz (or 30.72 MHz) onboard VCTCXO
  • VCTCXO may be tuned by onboard DAC
  • Reference clock input and output connector (U.FL)
• Dimensions: 50.8mm x 20.97mm (Mini PCIe form factor)
• Power sources:
  • USB connector (5 V)
  • Mini PCIe (3.3 V)

LimeSDR XTRX (bottom and top)

Board Overview

LimeSDR XTRX overview (top)

LimeSDR XTRX overview (bottom)

Manufacturing Plan

We have working prototypes and are ready to go into production using the same trusted manufacturing partners we’ve used to deliver other products in the Lime family. Our engineering team will be on site in Serbia for manufacturing and final assembly of LimeSDR XTRX. Being on site will allow us to adjust the production process very quickly and test the final product right away.

Fulfillment & Logistics

After completing production, we’ll send everything to Crowd Supply’s fulfillment partner, Mouser Electronics, who will distribute products to backers worldwide. You can learn more about Crowd Supply’s fulfillment service under Ordering, Paying, and Shipping in their guide.

Risks & Challenges

As is lately often the case, the biggest risk we face is supply chain uncertainty. From finding reliable sources of components, to being on site for production, we’ve made every effort to ensure smooth delivery to backers. Should something nonetheless go wrong, we’re committed to communicate openly and honestly about what’s going on and what we’re doing to fix it. We appreciate the trust you put in us!

LimeSDR XTRX is part of AMD FPGA Playground!