Introduction¶
LimeSDR Mini is low-cost software defined radio board. LimeSDR Mini development board provides a hardware platform for developing and prototyping high-performance and logic-intensive digital and RF designs based on Lattice Semiconductor’s ECP5 FPGA and Lime Microsystems transceiver.

Figure 1: LimeSDR Mini v2.2 board top view¶

Figure 2: LimeSDR Mini v2.2 board bottom view¶
LimeSDR Mini board features:
RF and BB parameters:
Configuration: SISO (1x TX, 1x RX)
Frequency range: 10 MHz – 3.5 GHz
Bandwidth: 30.72 MHz
Sample depth: 12 bit
Sample rate: 30.72 MSPS
Transmit power: max 10 dBm (depending on frequency)
USB 3.0 controller: FTDI FT601
FPGA: board is designed for Lattice ECP5 family LFE5U-25F/LFE5U-45F/LFE5U-85F FPGAs in 285-ball csfBGA package. By default board is assembled with LFE5U-45F-MG285 FPGA. Lattice ECP5 LFE5U-45F features:
285-pin csfBGA package (10 x 10 mm, 0.5 mm)
44 K LUTs logic capacity
108 sysMEM Blocks (18 Kb)
1944 Kb Embedded Memory
351 Kb distributed RAM
72x 18x18-bit multipliers
4x PLLs and 4x DLLs
118 IOs
FPGA configuration via JTAG
RF transceiver: Lime Microsystems LMS7002M
EEPROM Memory: 2x 128Kb EEPROMs for LMS MCU firmware and FPGA data (optional)
FLASH Memory: 128Mb Flash memory for FPGA configuration
Temperature sensor: LM75
General user inputs/outputs:
3x Dual colour (RG) LEDs
8x + 2x FPGA GPIO pinheaders (3.3V) (optional)
Connections:
USB 3.0 (type A) plug
Coaxial RF (SMA female) connectors
FPGA GPIO headers (unpopulated)
FPGA JTAG connector (unpopulated)
FAN (5V default or 3.3V) connector
Clock system:
40.00MHz on board VCTCXO
VCTCXO can be tuned by onboard DAC
Reference clock input and output connectors (U.FL)
Board size: 69mm x 31.4mm
Board power source: USB connector (5V)
For more information on the following topics, refer to the corresponding documents:
Board Overview¶
The heart of the LimeSDR Mini board is Lattice ECP5 (LFE5U-45F) FPGA. It’s main function is to transfer digital data between the PC through a USB 3.0 connector. The block diagram for LimeSDR Mini board is presented in the Figure 3.

Figure 3: LimeSDR Mini v2.2 Development Board Block Diagram¶
This section contains component location description on the board. LimeSDR Mini board picture with highlighted connectors and main components are presented in Figure 4 and Figure 5.

Figure 4: LimeSDR Mini v2.2 board top connectors and main components¶

Figure 5: LimeSDR Mini v2.2 board bottom connectors and main components¶
Description of board components is given in the Table 1.
Featured Devices |
||
---|---|---|
Board Reference |
Type |
Description |
IC1 |
RF transceiver |
Lime Microsystems LMS7002M |
IC7 |
FPGA |
Lattice Semiconductor’s LFE5U (LFE5U-45F) |
IC8 |
USB 3.0 microcontroller |
FTDI USB 3.0 to FIFO interface bridge chip FT601 |
Miscellaneous devices |
||
IC10 |
IC |
Temperature sensor LM75 |
Configuration, Status and Setup Elements |
||
J5 |
JTAG chain connector |
FPGA programming pin header on the board edge for JTAG cable, 0.1” pitch |
LED1, LED2, LED3 |
Red-green status LEDs |
User defined FPGA indication LED. |
General User Input/Output |
||
J3 |
Pin header |
8x FPGA GPIOs, 3.3V, 0.05” pitch |
J4 |
Pin header |
2x FPGA GPIOs on the board edge, 3.3V, 0.1” pitch |
J9 |
Pin header |
5V (3.3V voltage can be chosen by resistors) fan connection pin headers, 0.1” pitch |
Memory Devices |
||
IC2 |
IC |
I²C EEPROM Memory 128Kb (16 x 8), connected to RF transceiver I2C bus |
IC12 |
IC |
I²C EEPROM Memory 128Kb (16K x 8), connected to FPGA I2C bus |
IC15 |
IC |
Quad SPI Flash Memory 128 Mb (16M x 8) connected to FPGA SPI |
Communication Ports |
||
J6 |
USB 3.0 connector |
USB 3.0 (type A) plug |
Clock Circuitry |
||
XO1 |
VCTCXO |
40.00 MHz Voltage Controlled Temperature Compensated Crystal Oscillator |
IC11 |
IC |
10 bit DAC for TCXO (XT4) frequency tuning (default) |
IC16 |
IC |
16 bit DAC for TCXO (XT4) frequency tuning (unpopulated) |
IC17 |
IC |
Voltage reference (unpopulated) |
IC9 |
IC |
Clock buffer |
J8 |
U.FL connector |
Reference clock input |
J7 |
U.FL connector |
Reference clock output |
Power Supply |
||
IC14 |
IC |
Switching regulator LMZ20501 (1.8V rail) |
IC19 |
IC |
Switching regulator LMZ20501 (3.3V rail) |
IC13 |
IC |
Linear regulator LD39100PUR (1.1V rail) |
IC5 |
IC |
Linear regulator LD39100PUR (1.25V rail) |
IC6 |
IC |
Linear regulator LD39100PUR (1.4V rail) |
IC18 |
IC |
Linear regulator LD39100PUR (2.5V rail) |