Measurement Results for the Dynamic Supply CMOS RF Power Amplifie - Linear CMOS RF Power Amplifiers for Wireless Applications - page 41

Fig. 4.2 Dynamic supply PA (DSPA) evaluation board schematic diagram

p. 53]. In the photograph in Fig. 4.1 , the pin names are also shown so that the circuit
nodes with similar names (refer to Fig. 3.4 on p. 20,Fig.3.5 on p. 21, and Fig. 3.13
on p. 29) can be recognized. The total die area including pads is 1.35 mm 2 .
The evaluation board schematic is shown in Fig. 4.2 . The dynamic supply
PA IC includes the modulator and the power amplifier. Three adjustable current
sources [ 22 ] were used to bias the modulator. Their nominal values are I 1 = I 2 =

100 µA and I 3 = 5 µA. They can be adjusted with the potentiometers P 1 , P 2 , and

P 3 . The other external components are the inductor and capacitor that form the LC
filter, the flange-mount SMA connectors [ 10 ] used for the RF input and output, and
the SMB connector [ 11 ] for the envelope input. T L1 and T L2 are identical microstrip
transmission lines used in the input and output. Their width and length are 1100 µm
and 6200 µm, providing a characteristic impedance of Z 0 =

50 . Decoupling ca-
pacitors were also used in the supply rails and voltage bias nodes, but are not shown
in the figure. The measurement setup used in the characterization can be found in
Chap. 9 (Appendix A). The microstrip transmission lines at the input and output
influence the impedance matching. A procedure that helped matching the RF power
amplifier mounted on a printed-circuit board is described in Chap. 10 (Appendix B).
The main evaluation board whose schematic diagram is shown in Fig. 4.2 does
not include the envelope detector and processing blocks of Fig. 3.2 on p. 18. These
blocks were implemented in another PCB described in Sect. 4.3.1 , whose output is
connected to the “Env. Input” of the main evaluation board.