Data Sheet

SAM-M8Q - Data Sheet

UBX-16012619 - R04 Production Information Functional description

Page 12 of 25

1.17 Clock generation

1.17.1 Oscillators

The SAM-M8Q GNSS patch module comes with TCXO. The TCXO allows accelerated weak signal acquisition,

enabling faster start and reacquisition times.

TCXO used on the SAM-M8Q module is carefully selected and screened for stability and against frequency

perturbations across the full operating range (–40 °C to +85 °C).

The careful selection and qualification of critical parts, such as GNSS TCXOs, has resulted in u-blox modules

being the most reliable positioning modules in the industry, particularly in challenging conditions.

1.17.2 Real-Time Clock (RTC)

The RTC is driven by a 32 kHz oscillator using an RTC crystal. If the VCC_IO voltage fails, and a battery is

connected to V_BCKP, parts of the receiver switch off, but the RTC still runs providing a timing reference for the

receiver. This operating mode is called Hardware Backup Mode, which enables all relevant data to be saved in

the backup RAM to allow a hot or warm start later.

1.18 Power management

u-blox M8 technology offers a power-optimized architecture with built-in autonomous power saving functions

to minimize power consumption at any given time. Furthermore, the receiver can be used in two operating

modes: Continuous mode for best performance or Power Save Mode for optimized power consumption.

1.18.1 DC/DC converter

The SAM-M8Q GNSS patch antenna module integrates a DC/DC converter, allowing reduced power

consumption.

For more information see the SAM-M8Q Hardware Integration Manual [1].

1.18.2 Power Mode Setup

u-blox M8 modules can be configured to run in either continuous or a choice of Power Save mode

configurations. A template of power mode settings can be used to easily select typical power mode setups to

cover the majority of users’ requirements.

For specific power saving applications, the user has the option to fully configure via the power save mode

configuration.

The u-blox M8 modules’ power mode setup offers a choice of continuous operation and preset Power Save

Mode Configurations.

 Continuous (default) mode for best GNSS performance vs. power consumption

 Continuous with no compromise in power consumption

 A 1 Hz cyclic tracking mode for aggressive power reduction

 Choice of 2 or 4 Hz

cyclic tracking modes for typical wearable applications

 ON/OFF interval mode

1.18.3 Continuous Mode

Continuous Mode uses the acquisition engine at full performance resulting in the shortest possible TTFF and the

highest sensitivity. It searches for all possible satellites until the Almanac is completely downloaded. The receiver

then switches to the tracking engine to lower power consumption.

Thus, a lower tracking current consumption level will be achieved when:

 A valid GNSS position is obtained

Single GNSS constellation configuration only