STM32WB09XE datasheet(10/73 Pages) STMICROELECTRONICS

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3.7

RF subsystem

The STM32WB09xE embeds an ultra-low power radio, compliant with Bluetooth® LE specification. The device

radio offers 1 Mbit/s and 2 Mbit/s transfer rates as well as long range options (125 Kbit/s, 500 Kbit/s), supports

multiple roles simultaneously acting at the same time as Bluetooth® LE sensor and hub device.

The Bluetooth® LE protocol stack is implemented by an efficient system partitioned as follows:

•

Hardware part: BlueCore handling time critical and time consuming Bluetooth® LE protocol parts

•

Firmware part: Arm® Cortex®-M0+ core handling non time critical Bluetooth® LE protocol parts

3.7.1

RF front-end block diagram

The RF front-end is based on a direct modulation of the carrier in TX, and uses a low IF architecture in RX mode.

Thanks to an internal transformer with RF pins, the circuit directly interfaces the antenna (single ended

connection, impedance close to 50 Ω). The natural band pass behavior of the internal transformer simplifies

outside circuitry aimed at harmonic filtering and out of band interferer rejection.

In transmit mode, the maximum output power is user selectable through the programmable LDO voltage of the

power amplifier. A linearized, smoothed analog control offers a clean power ramp-up.

In receive mode, the automatic gain control (AGC) can reduce the chain gain at both RF and IF locations, for

optimized interferer rejections. Thanks to the use of complex filtering and highly accurate I/Q architecture, high

sensitivity and excellent linearity can be achieved.

Figure 3. STM3WB09xE RF block diagram

Note:

VFQFPN32: VSS through exposed pad, and VSSRF pins must be connected to ground plane

WLCSP36: VSSRF pins must be connected to ground plane

RADIO_TX_SEQUENCE

RADIO_RX_SEQUENCE

STM32WB09xE

Functional overview

DS14210 - Rev 6

page 10/73

STM32WB09XE bảng dữ liệu(PDF) 10 Page - STMicroelectronics