STM32W108B-SK STMicroelectronics, STM32W108B-SK Datasheet - Page 12

• Manufacturer Part Number: STM32W108B-SK
• Description: STARTER KIT FOR STM32W108
• Manufacturer: STMicroelectronics
• Series: STM32r
• Type: MCUr

Specifications of STM32W108B-SK

• Featured Product: STM32 Cortex-M3 Companion Products
• Contents: Board
• Silicon Manufacturer: ST Micro
• Core Architecture: ARM
• Core Sub-architecture: Cortex - M3
• Silicon Core Number: STM32
• Silicon Family Name: STM32W108xx
• Kit Contents: Board
• Features: IEEE
• Mfg Application Notes: STM32W108 Adjacent Channel Rejection Measurements
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: *
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Non-RF design considerations
3.3
3.4
3.5
3.6
12/14
1.8V regulator load capacitor
The STM32W operates over a supply voltage (V
regulator converts V
2.2 µF ceramic loading capacitor is required on the output of VREG_OUT of the STM32W. A
series resistor (R5) is used to keep the minimum ESR of the loading capacitor below 1 Ohm.
This is shown in
Figure 8.
1.2V regulator loading
The STM32W contains an integrated 1.2V Regulator to drive the Core Logic. By driving the
core at this lower V
regulated voltage, a PCB designer should connect pin VDD_CORE_0 to pin VDD_CORE_1.
If you would like to drive the core at 1.8V, then the 1.8V net should be connected to both
pins VDD_CORE_0 and VDD_CORE_1.
A 1µF ceramic loading capacitor should be placed close to pin VDD_CORE_0. In addition, a
10nF decoupling capacitor should be place close to pin VDD_CORE_1.
1.8V net decoupling
To minimize noise and coupling paths into the STM32W, decoupling capacitors must be
placed on each of the VDD pins. All decoupling capacitors should be placed as close to the
STM32W as possible as well as in between the source point (via) and the STM32W pin. In
addition, all values should be maintained as defined by the STM32W Reference Design.
1.8V analog to 1.8V digital filtering
To keep the Radio Active current at 36 mA, ST recommends adding a single element filter
(resistor) between the digital and analog 1.8V nets, 1.8V_A and 1.8V_D, respectively (see
Figure
STM32W. If this resistor is not used, the RX current will increase by 1mA to 37mA.
9). This resistor maintains a reduced bias current for the digital logic within the
1.8V regulator loading capacitance
Figure
DD
BRD
potential, reduced current consumption is achieved. To utilize this
8.
down to a trimmed 1.8V. To stabilize the integrated regulator, a
Doc ID 17406 Rev 3
BRD
) of 2.1 to 3.6V. An integrated 1.8V
AN3206