ST Nucleo-64 STM32WL3 Series User Manual page 19

7.8 RF stage
The RF front end is designed to match and filter RF on three different paths: TX, RX, and RX_WAKEUP.
NUCLEO-WL33CCx embeds an IPD (integrated passive device) that combines both TX and RX matching and
filtering in a tiny package.
STM32WL33CC has two output power pins TX and TX_HP that are used in this way:
• TX pin alone is used for output power up to 10 dBm.
• TX_HP pin alone is used for output power up to 16 dBm.
• Above 16 dBm, both TX and TX_HP pins are used.
On NUCLEO-WL33CCx, only the TX_HP pin is connected for output power up to 16 dBm.
SMPS biases internal PA, SMPS being in the range of 1.2 to 2.4 V
The board comes with a shield can. This shield can must not be removed.
The antenna is glued to the SMA connector. A different reference antenna is used for lower and higher bands:
• NUCLEO-WL33CC1 is equipped with an LPRS SR-900 antenna.
• NUCLEO-WL33CC2 is equipped with an LPRS SR-433 antenna.
VFBSD
VLXSD
VDD
VDDSD
VDDRF
OSCOUT
48 MHz X2
OSCIN
NUCLEO-WL33CCx board variants embed a different IPD.
for each variant.
NUCLEO-WL33CCx variant
NUCLEO-WL33CC1
NUCLEO-WL33CC2
The antenna is stuck to the SMA connector because of FCC constraints. Indeed, it is mentioned in the FCC
regulations. As soon as a product is considered general public, the FCC implies that the antenna must be stuck to
the board connector with epoxy glue. Refer to the FCC documentation BASIC EQUIPMENT AUTHORIZATION
GUIDANCE FOR ANTENNAS USED WITH PART 15 INTENTIONAL RADIATORS in the chapter ANTENNA
REQUIREMENTS—Section 15.203.
UM3418 - Rev 1
Figure 12 gives a representation of external and internal RF blocks.
Figure 12.
PA
SMPS
PA
STM32WL33CC RF overview
Table 7. IPD manufacturer part number used on NUCLEO-WL33CCx
RF block diagram
TX
TX_HP
IPD
(integrated passive
device)
RX
RX_LPAWUR
LPAWUR matching
Table 7 gives the part number and a description of IPD
Part number
MLPF-WL-01D3
MLPF-WL-04D3
UM3418
Hardware layout and configuration
Antenna
Description
IPD for STM32WL3xxx, 826‑958MHz,
16 dBm, on a 4‑layer PCB
IPD for STM32WL3xxx, 413‑479MHz,
16 dBm, on a 4‑layer PCB
page 19/39