adl5382 Analog Devices, Inc., adl5382 Datasheet - Page 20

• Manufacturer Part Number: adl5382
• Description: 700 Mhz To 2.7 Ghz Quadrature Demodulator
• Manufacturer: Analog Devices, Inc.

ADL5382
As the load impedance of the filter increases, the filter design
becomes more challenging in terms of meeting the required
rejection and pass band specifications. In the previous W-
CDMA example, the 500 Ω load impedance resulted in the
design of a sixth-order filter that has relatively large inductor
values and small capacitor values. If the load impedance is 200 Ω,
the filter design becomes much more manageable. As shown in
Figure 54, the resultant inductor and capacitor values become
much more practical.
Figure 55 and Figure 56 illustrate the magnitude response and
group delay response of the fourth-order filter, respectively.
Figure 54. Fourth-Order Low-Pass W-CDMA Filter Schematic
10µH
10µH
8µH
8µH
Rev. 0 | Page 20 of 28
Figure 56. Fourth-Order Low-Pass W-CDMA Filter Group Delay Response
Figure 55. Fourth-Order Low-Pass W-CDMA Filter Magnitude Response
–10
–15
–20
–5
5
0
0.2
0.2
0.6
0.4
1.0
0.6
1.4
0.8
FREQUENCY (MHz)
FREQUENCY (MHz)
1.8
1.0
2.2
1.2
2.6
1.4
3.0
1.6
3.4
1.8
3.8
2.0