There is a 10 dB difference in sensitivity between the maximum and minimum transmitter power for B7. Removing the B40 PRX matching network eliminates the issue. With insufficient port-to-port isolation, the B7 TX couples to the B40 port and then couples again to the B7 PRX trace from the B40 PRX trace. There are two proposed solutions: using a switch with at least 32 dB of port-to-port isolation or enhancing the trace isolation between the B40 and B7 PRX traces through a layout modification.

1. 1

2. Transceiver
Switch
B7_B40 TX
B40 PRX
HB_PAB7_B40 TX
B40 TRX
B7 TX
B7 PRX
ASM
PRX
Matching
PRX
Matching
Introduction
 For B7, there is 10 dB difference in sensitivity between
maximum and minimum transmitter power. And the
block diagram is as below:
2

3. Introduction
 Remove B40 PRX matching network, the issue
disappears.
Transceiver
Switch
B7_B40 TX
B40 PRX
HB_PAB7_B40 TX
B40 TRX
B7 TX
B7 PRX
ASM
PRX
Matching
3

4. Introduction
 With insufficient port-to-port isolation, B7 TX couples to
B40 port, and couples to B7 PRX trace from B40 PRX
trace again.
Transceiver
Switch
B7_B40 TX
B40 PRX
HB_PAB7_B40 TX
B40 TRX
B7 TX
B7 PRX
PRX
Matching
PRX
Matching
Due to insufficient
port-to-port isolation
Due to close trace
4

5. Introduction
 Because the couple path is :
we have to two solutions :
 Change a switch with sufficient port-to-port isolation
(at least 32 dB)
 With layout modification, enhance the isolation between B40
and B7 PRX traces.
5