ISL55016 Datasheet, PDF (9/11 Pages) Intersil Corporation – MMIC Silicon Bipolar Differential Amplifier

ISL55016
RF IN
GND
L
L
ISL55012
C
C
C
C
R
C
L
VDD
C
C _DIFFERENTIAL
OUT
BALUN
C
C
RF IN
VDD
C
GND
L
R
C
VDD
DIFFERENTIAL
OUT
C
C
ISL55016
C
L
R
VDD
FIGURE 30. COMPARISON OF ISL55012 WITH A BALUN AND ISL55016 (RELATIVE SIZE)
100ٛΩ
VDD
C3
C2
C1
50Ωٛ
50ٛΩ RF OUT
100ٛΩ
L2
L1
100ٛΩ
RF IN
75ٛΩ
RF OUT
50ٛΩ
FIGURE 31. PCB LAYOUT OF MATCHING NETWORK
Trade-off Between Power and OIP2
The values of R₁ and R₂ (Figure 29) have two options; 27Ω
and 0Ω. Decreasing the R₁ and R₂ value will increase the
voltage across the output transistor leading to an increase in
the dissipation power. At the same time, it will increase the
amplitude of the compression, OIP2 and OIP3. Figures 21, 22
and 26 show this effect on OIP2. Figure 25 shows the
compression point changed with different resistors. Figure 28
shows the OIP3 changed with different resistors. One needs
to trade-off between the power dissipation and higher OIP2.
Matching at the Input and Output
In the PCB Layout Design, a matching network is needed,
especially at the input. Figure 31 shows the matching
network used for the ISL55016 Evaluation Board. 12mm
100Ω trace and 6mm 50Ω trace are used to form the input
matching network and 4mm 100Ω trace to form the output
matching network on the FR4 material.
In Figure 31, the S11 is improved at 2GHz with the matching
network, to less than -10dB.
9
FN6526.1
June 24, 2008