BC352239A Datasheet, PDF (40/116 Pages) List of Unclassifed Manufacturers – BlueCore 3-Multimedia External

Device Terminal Descriptions
8 Device Terminal Descriptions
8.1 RF Ports
The BlueCore3-Multimedia External RF_IN terminal can be configured as either a single ended or differential
input. The operational mode is determined by the setting the PS Key PSKEY_TXRX_PIO_CONTROL (0x20).
8.1.1 TX_A and TX_B
TX_A and TX_B form a complementary balanced pair. On transmit, their outputs are combined using a balun into
the single-ended output required for the antenna. Similarly, on receive, their input signals are combined internally.
Both terminals present similar complex impedances that require matching networks between them and the balun.
Starting from the substrate (chip side), the outputs can each be modelled as an ideal current source in parallel
with a lossy resistance and a capacitor. The bond wire can be represented as series inductance.
BlueCore3-Multimedia External
PA
_
L2
1.5nH
PA
+
RF
Switch
R2
10 Ω
0.9pF
+
LNA
_
RF
Switch
R3
10 Ω
0.9pF
L3
1.5nH
Figure 8.1: Circuit TX/RX_A and TX/RX_B
BC352239A-ds-001Pc
© Cambridge Silicon Radio Limited 2004
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