LEA-M8F - u-blox M8 time & frequency reference GNSS modules

The LEA-M8F provides multi-GNSS synchronisation for cost-sensitive network edge equipment including Small Cell and Femto wireless base-stations.

The LEA-M8F provides multi-GNSS synchronisation for cost-sensitive network edge equipment including Small Cell and Femto wireless base-stations. The LEA-M8F module is a fully self-contained phase and frequency reference based on GNSS, but can also be used as part of a complete timing sub-system including macro-sniff Synchronous Ethernet and packet timing.

The LEA-M8F module includes a low-noise 30.72 MHz VCTCXO meeting the master reference requirements for LTE Small Cells and providing 100 ppb autonomous hold-over. An external TCXO or OCXO can also be measured and controlled for TDLTE, LTE-Advanced and other applications requiring extended hold-over. External sources of synchronization are supported through time-pulse and frequency inputs and a message interface. This allows measurements from macro-sniff, Sync-E or packet timing to be combined with measurements from GNSS.

u-blox time and frequency products include timing integrity alarms that report phase and frequency uncertainty both during normal operation and hold-over. They feature a high dynamic range radio with both analog and digital interference mitigation supporting their inclusion as an integral part of a local area base station design.

Key Features:

  • Reception of GPS, QZSS, GLONASS, BeiDou
  • Integral low phase-noise 30.72 MHz system reference oscillator disciplined by GNSS
  • Accurate measurement and control of external oscillators
  • High sensitivity acquisition and single-satellite timing
  • Automatic hold-over
  • Prepared for integration with external PTP, Sync-E and network listen

Example application (Small Cell):

In a wireless Small Cell application, the LEA-M8F can distribute a disciplined low-phase noise 30.72 MHz reference signal directly to the RF transceivers. GNSS synchronisation is combined with network sources by an exchange of synchronisation signals, status and control messages with the base-band processor. Source selection and hold-over may be controlled by either the LEA-M8F or base-band application.


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Parameters Specifications
Receiver type

72-channel u-blox M8 engine



Galileo-ready E1B/C (subject to firmware upgrade)

2.5m CEP 4.0m CEP
Cold starts 26s 30s
Aided cold starts 2s 8s
Tracking -165dBm -165dBm
Cold starts: Aided -157dBm -148dBm
Cold starts: Autonomous -148dBm -145dBm
Reacquisition -160dBm -157dBm
Assistance GNSS

AssistNow Online

OMA SUPL & 3GPP compliant

Internal oscillator VCTCXO
Noise figure

On-chip LNA

Extra LNA for lowest noise figure

Anti jamming

Active CW detection and removal

Extra on-board SAW band pass filter

Supported antennas Active and passive
Internal SQI Flash For firmware update

Features - Synchronisation

Frequency output 30.72 MHz disciplined
Phase noise
10 Hz: -90 dBc/Hz
10 kHz: -143 dBc/Hz
100 Hz: -120 dBc/Hz
100 kHz: -145 dBc/Hz
1 kHz: -130 dBc/Hz 1 MHz: -149 dBc/Hz
Jitter (100 Hz - 1 MHz)
EVM (100 Hz - 1 MHz @ 2100 MHz)
Frequency control (internal oscillator)

GNSS locked: 5 ppb

Hold-over: 100 ppb, 24 hr

Frequency control (external oscillator)

Resolution: < 5 ppb

Frequencies: 10, 13, 19.2, 20, 26, 30.72, 40 MHz

Hold-over: Determined by external oscillator

Phase control

Clear sky: < 20 ns

Indoor: < 500 ns typ

Time-pulse input Resolution: <50 ns
Time-pulse output Jitter: <2 ns
Time-pulse frequency 0.5 Hz to 2 Hz
Serial interfaces

SPI or UART and DDC (I2 C compliant)

USB v2.0 full speed (ext. voltage regulator)

Protocols NMEA, UBX binary, RTCM
Timing interfaces

Timepulse output

2x timepulse/frequency inputs

Electrical data
Supply voltage 3.0 to 3.6 V
Power consumption

41 mA @ 3.3 V

Environmental data, quality & reliability
Operating temperature -40°C to +85°C
RoHS compliant (lead free)
Qualification according to ISO 16750
Manufactured in ISO/TS 16949 certified production sites



28 pin LCC (Leadless Chip Carrier): 17.0 x 22.4 x 3.5 mm, 2.0 g

Part Number Description Pack Size
LEA-M8F-0 u-blox M8 Time & Frequency module, VCTCXO, 17 x 22.4 mm
Reel of 250
EVK-M8F u-blox M8 Time & Frequency Reference Evaluation Kit, supports LEA-M8F Each

EVK-8 / EVK-M8 evaluation kits enable simple evaluation of the high performance u-blox 8 and u-blox M8 positioning technology. The built-in USB interface provides both power supply and high-speed data transfer, and eliminates the need for an external power supply.

u-blox 8 and M8 evaluation kits are compact, and their user-friendly interface and power supply make them ideally suited for use in laboratories, vehicles and outdoor locations. Furthermore, they can be used with a PDA or a notebook PC, making them the perfect companion through all stages of design-in projects.



  • Easy to use
  • Extensive visualization and evaluation features
  • Supports AssistNow Online and AssistNow Offline A-GNSS services
  • 1 USB port, 1 UART port, 1 I²C/SPI port (switchable)
  • All ports accessible outside
  • Power supply and data transfer over USB (USB V2.0 compatible)

The EVK-8 / EVK-M8 download includes u-center, which is an interactive tool for configuration, testing, visualization and data analysis of positioning chips and modules. u-center provides useful assistance during all phases of a system integration project.

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Last updated: 23 August 2016