NXP Semiconductors
AN13125
IW416 Design Guide
6.2 RF front-end for WLCSP package
Similar to QFN package, WLCSP package can also be configured as single or dual
antenna front-end application. WLCSP package requires an external RF SPDT switch on
5 GHz Wi-Fi path to provide additional rejection to out-of-band emissions. The following
RF front-end components must be used to reduce out-of-band emissions.
•
RF SPDT switch on Wi-Fi 5 GHz path
•
Bandpass-bandpass structure diplexer
shows a typical front-end topology for dual antenna applications.
Figure 19. RF front-end with dual antenna applications
Use discrete low pass filters (LPF) to ensure the rejection of out-of-band emissions. LPF
components also act as impedance matching circuits between the wireless SoC pin
and the diplexer part on the PCB. For maximum power transfer in RF, the input/output
impedance needs to match 50 Ω. Refer to
for filter circuit on Wi-Fi 2.4 GHz path
for the filter circuit on Bluetooth path.
AN13125
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Application note
Rev. 1 — 26 May 2021
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