Lime Microsystems has upgraded its LimeSDR Mini product with a more powerful successor called the LimeSDR Mini 2.2.
The original LimeSDR Mini had a successful launch in 2017 where they raised over $2.2M – well in excess of the $100,000 target. The team has since then shipped tens of thousands of units to engineers around the world for use in a range of applications from radio experimentation to satellite monitoring and more. The product has been used by hobbyists and integrated into commercial products alike.
In 2021, the product like many others has been impacted by global chip shortages. The company has been challenged by the availability of critical semiconductor ICs like FPGAs and PLLs to even commodity passive components. However, now they have overcome these issues to announce a brand new product – the LimeSDR Mini 2.2.
Architecture
The LimeSDR Mini 2.0, retains the same transceiver radio chip – the LMS7002M. However now they have replaced the Intel MAX 10 FPGA with a Lattice Semiconductor ECP5. This dramatically increases the number of programmable logic gates on-board from 16k to 44k.
The larger FPGA provides more room for on-board digital signal processing and also real-time processing with lower latency relative to what you can accomplish on a PC. Plus the design is open source and the possibilities for experimentation are endless.
Specifications
The specifications of the product match that of the original LimeSDR Mini. Let’s take a closer look and what each one means
| Frequency Range | 10 MHz – 3.5 GHz | Covers most popular bands including FM, Airband, AIS, 4G/LTE and more |
| RF Bandwidth | 40 MHz | Enables wideband signal processing |
| ADC Sample Depth | 12 bits | Good dynamic range |
| Sample Rate | 30.72 MS/s | Multiple of 1.2288 which makes 4G signal processing easier |
| Interface | USB 3.0 | Fast interface to the host PC |
| Oscillator Precision | ±1 ppm initial, ±4 ppm stable | Good accuracy and stability for a variety of applications |
| Programmable Logic Gates | 44,000 | More processing power over previous generation |
The Competition
Some of the major pros of the Lime Mini 2.0 over the competition are:
- Full-duplex operation with separate Tx and Rx ports. As mentioned in this post a separate receiver input allows for optimization of the receive signal with the use of a low-noise amplifier – something you cannot do with either the HackRF or the RTL-SDR
- Wide bandwidth of 40 MHz which exceeds that of HackRF (20 MHz) and RTL-SDR (3.2 MHz)
- Ability to work with the on-board FPGA – this is a powerful capability as not many SDR vendors allow you to do this
We have written a detailed comparison between the Lime Mini and HackRF
Summary
The LimeSDR Mini 2.0 is an exciting evolution of a popular open-source software-defined radio platform. The radio transceiver and signal processing specifications are very compelling and this product will find a wide range of applications in both commercial and hobbyist markets.
