Infineon AIROC CYW20835, Руководство пользователя, Страница: 5 / 11

User Guide 5 of 11 002-34024 Rev. **
2021-10-05
AIROC™ CYW20835 Bluetooth® LE system on chip hardware design
guidelines
Component placement
2.4
Decoupling capacitors
See the reference schematic for decoupling capacitor usage and values on different power domains. Infineon
recommends that you use the vendor and part numbers shown in the reference design BOM. Decoupling
capacitors must be placed as close to its associated pin as possible.
2.5 Ground vias
Do not use long thin traces to connect components to ground vias; doing so adds inductance that can
significantly alter circuit performance.
2.6 Bandpass filter
Place a chip bandpass filter between the antenna matching components and the CYW20835 device to attenuate
harmonics from CYW20835. The chip band pass filter part used in the CYW20835 reference design is Murata,
LFB182G45CL3D178.A microstrip is used for all connections of the bandpass filter.
Insertion loss and out
‐
of
‐
band attenuation performance depend on PCB component layouts and tolerances.
Filter layout should follow general RF layout rules.
2.7 Analog mic signals
Place a series 0.1-µF capacitor for each of the analog MIC signals, MIC_P and MIC_N. MIC_P and MIC_N should
also be routed within the analog ground (GND_A) area as shown in
Figure 3 . Use net ties to shown in Figure 3
to stitch GND_A to the main ground. The analog MIC is powered by the CYW20835 ’s MIC_BIAS pad by default.
Figure 3 Bandpass filter and decoupling capacitors