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

Sub-GHz radio (SUBGHZ)

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
only, allow an optimal trade-off between range, data rate and power consumption. This sub-
GHz radio is compliant with the LoRaWAN
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 + 14 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
154/1461
®
, (G)FSK/(G)MSK modulation in transmit and receive, and (D)BPSK in transmit
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
MSK and GMSK RX/TX with BR from 1.2 to 300 Kbit/s and TX only with BR from
0.1 to 1.2 Kbit/s
BPSK and DBPSK TX only with bit rate for 100 and 600 bit/s
LoRa modulation
(G)FSK modulation
(G)MSK modulation
(D)BPSK modulation
+ f where f is the local RF-PLL oscillator frequency, f
rf if lo
is the intermediate frequency
if
®
specification v1.0 and radio regulations
RM0453 Rev 1
RM0453
is the wanted receive
rf