Sub-Ghz Radio (Subghz); Sub-Ghz Radio Introduction; Sub-Ghz Radio Main Features - STMicroelectronics STM32WL5 Series Reference Manual

RM0453
5

Sub-GHz radio (SUBGHZ)

5.1

Sub-GHz radio introduction

The sub-GHz radio is an ultra-low-power sub-GHz radio operating in the 150 - 960 MHz ISM
band. LoRa
in transmit only, allow an optimal trade-off between range, data rate and power
consumption. This sub-GHz radio is compliant with the LoRaWAN
radio regulations including ETSI EN 300 220, EN 300 113, EN 301 166, FCC CFR 47 part
15, 24, 90, 101 and the ARIB STD-T30, T-67, T-108.
Features related to the LoRa modulation are only available on STM32WL55xx devices, that
support LoRa.
The sub-GHz radio consists of:
•
an analog front end transceiver, capable of outputting + 15 dBm maximum power on its
RFO_LP pin and + 22 dBm maximum power on RFO_HP pin
•
a digital modem bank providing the following modulation schemes:
–
–
–
–
•
a digital control comprising all data processing and sub-GHz radio configuration control
•
a high-speed clock generation
5.2

Sub-GHz radio main features

The main features of the sub-GHz radio are listed below:
•
Half-duplex 150 - 960 MHz ISM sub-GHz radio transceiver supporting:
–
–
–
–
•
Programmable output power up to + 22 dBm
•
Low-IF architecture, mixing the RF receive signal with a signal tone located in the
negative frequency
f = - f
lo
signal and f
•
Automatic I/Q calibration to improve image rejection
®
and (G)FSK modulation in transmit and receive, and BPSK/(G)MSK
LoRa Rx/Tx with bandwidth (BW) from 7.8 - 500 kHz, spreading factor (SF)
5 - 12, bit rate (BR) from 0.013 to 17.4 Kbit/s (real bitrate)
FSK and GFSK Rx/Tx with BR from 0.6 to 300 Kbit/s
(G)MSK Tx with BR from 0.1 to 10 Kbit/s
BPSK Tx with bitrate for 100 and 600 bit/s
LoRa modulation
(G)FSK modulation
(G)MSK Tx modulation
BPSK Tx modulation
+ f where f is the local RF-PLL oscillator frequency, f
rf if lo
is the intermediate frequency
if
RM0453 Rev 5
Sub-GHz radio (SUBGHZ)
®
specification v1.0 and
is the wanted receive
rf
155/1450
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