AN3206

Reference design

Doc ID 17406 Rev 3

3/14

2

Reference design

Figure 1 shows a block diagram of the reference design.

Figure 1.

Block diagram of STM32W108 reference design (48-pin package)

The STM32W108 reference design uses an external 50/100 Balun as its primary RF

component. It provides an unbalanced to differential 50-to-100 Ohms conversion to present

the STM32W108 with its optimal load. A single inductor makes up the matching network and

optimizes RF performance. A band pass filter keeps the conducted harmonics within FCC

and ETSI limits.

Due to the market demand that IEEE 802.15.4 software maximize their communication

range, this design has been optimized accordingly. In Boost mode, the STM32W108

reference design achieves a high transmit output power across the 16 channels. This

section describes the design decisions behind each of the items shown in Figure 1.