SLWSTK6020A Datasheet, PDF (8/102 Pages) Silicon Laboratories – EFR32BG1 Blue Gecko Bluetooth® Smart SoC Family Data Sheet

EFR32BG1 Blue Gecko Bluetooth® Smart SoCFamily Data Sheet
System Overview
3.3 Power
The EFR32BG1 has an Energy Management Unit (EMU) and efficient integrated regulators to generate internal supply voltages. Only a
single external supply voltage is required, from which all internal voltages are created. An optional integrated DC-DC buck regulator can
be utilized to further reduce the current consumption. The DC-DC regulator requires one external inductor and one external capacitor.
AVDD and VREGVDD need to be 1.85 V or higher for the MCU to operate across all conditions; however the rest of the system will
operate down to 1.62 V, including the digital supply and I/O. This means that the device is fully compatible with 1.8 V components.
Running from a sufficiently high supply, the device can use the DC-DC to regulate voltage not only for itself, but also for other PCB
components, supplying up to a total of 200 mA.
3.3.1 Energy Management Unit (EMU)
The Energy Management Unit manages transitions of energy modes in the device. Each energy mode defines which peripherals and
features are available and the amount of current the device consumes. The EMU can also be used to turn off the power to unused RAM
blocks, and it contains control registers for the dc-dc regulator and the Voltage Monitor (VMON). The VMON is used to monitor multiple
supply voltages. It has multiple channels which can be programmed individually by the user to determine if a sensed supply has fallen
below a chosen threshold.
3.3.2 DC-DC Converter
The DC-DC buck converter covers a wide range of load currents and provides up to 90% efficiency in energy modes EM0, EM1, EM2
and EM3, and can supply up to 200 mA to the device and surrounding PCB components. Patented RF noise mitigation allows operation
of the DC-DC converter without degrading sensitivity of radio components. Protection features include programmable current limiting,
short-circuit protection, and dead-time protection. The DC-DC converter may also enter bypass mode when the input voltage is too low
for efficient operation. In bypass mode, the DC-DC input supply is internally connected directly to its output through a low resistance
switch. Bypass mode also supports in-rush current limiting to prevent input supply voltage droops due to excessive output current tran-
sients.
3.4 General Purpose Input/Output (GPIO)
EFR32BG1 has up to 31 General Purpose Input/Output pins. Each GPIO pin can be individually configured as either an output or input.
More advanced configurations including open-drain, open-source, and glitch-filtering can be configured for each individual GPIO pin.
The GPIO pins can be overridden by peripheral connections, like SPI communication. Each peripheral connection can be routed to sev-
eral GPIO pins on the device. The input value of a GPIO pin can be routed through the Peripheral Reflex System to other peripherals.
The GPIO subsystem supports asynchronous external pin interrupts.
3.5 Clocking
3.5.1 Clock Management Unit (CMU)
The Clock Management Unit controls oscillators and clocks in the EFR32BG1. Individual enabling and disabling of clocks to all periph-
eral modules is perfomed by the CMU. The CMU also controls enabling and configuration of the oscillators. A high degree of flexibility
allows software to optimize energy consumption in any specific application by minimizing power dissipation in unused peripherals and
oscillators.
3.5.2 Internal and External Oscillators
The EFR32BG1 supports two crystal oscillators and fully integrates four RC oscillators, listed below.
• A high frequency crystal oscillator (HFXO) with integrated load capacitors, tunable in small steps, provides a precise timing refer-
ence for the MCU. Crystal frequencies in the range from 38 to 40 MHz are supported. An external clock source such as a TCXO can
also be applied to the HFXO input for improved accuracy over temperature.
• A 32.768 kHz crystal oscillator (LFXO) provides an accurate timing reference for low energy modes.
• An integrated high frequency RC oscillator (HFRCO) is available for the MCU system, when crystal accuracy is not required. The
HFRCO employs fast startup at minimal energy consumption combined with a wide frequency range.
• An integrated auxilliary high frequency RC oscillator (AUXHFRCO) is available for timing the general-purpose ADC and the Serial
Wire debug port with a wide frequency range.
• An integrated low frequency 32.768 kHz RC oscillator (LFRCO) can be used as a timing reference in low energy modes, when crys-
tal accuracy is not required.
• An integrated ultra-low frequency 1 kHz RC oscillator (ULFRCO) is available to provide a timing reference at the lowest energy con-
sumption in low energy modes.
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