The pins 17 (VBWA) and 16 (RFOUT1) are DC connected internally. This explains the circuit on Figure 4 (VDD2A is connected to VBWA).
The VBW leads are connected to an internal RF cold spot in the internal output matching circuit.
The characterization reference design utilizes these leads to provide the VDD stage two drain bias, and the leads are RF decoupled to
ground with some bias caps.
The purpose of this bias structure is to reduce the effective lead inductance between the die and the external bias decoupling caps to
improve the VBW capability of the device. Most other RF IC parts of this size, MW7IC2725N have VBW rating in the 90 MHz range. With this
alternative biasing structure, the VBW is 170 Mhz.
There is some RF power loss thru these leads and if a wide VBW is not required, then the part can be biased in a normal manner thru an RF
choke on the drain lead and achieve better RF performance.
It is a designer’s option, wider VBW or better RF.
Have a great day,
Pavel
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