PE64907
Product Specification
Series Operation
In Series configuration, the effective capacitance
between RF+ and RF- ports is represented by C
s
and tuning ratio as C
Smax
/C
Smin
.
Figure 13. Effective Capacitance Diagram
Figure 15. Measured Series S
11
/S
22
(major states)
S
11
C0
S
22
C0
S
11
C1
S
22
C1
S
11
C2
S
22
C2
S
11
C4
S
22
C4
S
11
C8
S
22
C8
S
11
C15
S
22
C15
S
11
C31
Frequency(.3 - 3000 MHz)
S
22
C31
Shunt Configuration (looking into RF+ when RF- is
grounded) will have higher total capacitance at RF+
due to parallel combination of Cs with parasitic
capacitance C
P1
(C
S
+ C
P1
), as demonstrated in
Figure 14
and
Table 9.
Figure 14. Typical Capacitance vs. State
3.0
2.5
Figure 16. Measured Series S
21
vs. Frequency
0
-5
-10
-15
dB(S
21
)
-20
-25
-30
-35
C0
C1
C2
C4
C8
C16
C31
0
0.5
1
1.5
2
Frequency (GHz)
2.5
3
Capacitance
2.0
1.5
1.0
0.5
0.0
0
5
10
15
State
Capacitance in Series
Configuration (Cs)
Capacitance in Shunt
Configuration (Cs+Cp1)
20
25
30
-40
Table 9. Effective Capacitance Summary
Configuration
Series (RF+ to RF-)
Shunt (RF+ to GND)
Effective
Capacitance
C
S
C
S
+ C
P1
C
min
(state 0)
0.38
0.85
C
max
Tuning
(state 31) Ratio
2.12
2.4
5.58:1
2.82:1
When the DTC is used as a part of a reactive
network, impedance transformation may cause the
internal RF voltages (V
P
and V
M
in
Figure 12)
to
exceed peak operating RF voltage. The complete
RF circuit must be simulated using actual input
power and load conditions to ensure neither V
P
nor
V
M
exceeds 30 Vpk.
S
11
and S
21
for series configuration is illustrated in
Figures 15
and
16.
S
21
includes mismatch and
dissipative losses and is not indicative of tuning
network loss. Equivalent Circuit Model can be used
for simulation of tuning network loss.
Document No. DOC-30214-2
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