ADL5350 Analog Devices, Inc., ADL5350 Datasheet - Page 20

• Manufacturer Part Number: ADL5350
• Description: Lf To 4 Ghz High Linearity Y-mixer
• Manufacturer: Analog Devices, Inc.

ADL5350
Figure 63 depicts a crossover filter network approach to provide
isolation between the RF and IF ports for a downconverting
application. The cross-over network essentially provides a high-
pass filter to allow the RF signal to pass to the RF/IF node (Pin 1
and Pin 8), while presenting a low-pass filter (which is actually
a band-pass filter when considering the DC blocking capacitor,
C
passed to the desired IF load.
When designing the RF port and IF port networks, it is
important to remember that the networks share a common
node (the RF/IF pins). In addition, the opposing network presents
some loading impedance to the target network being designed.
AC
). This allows the difference component (f
Figure 63. 3.3 GHz to 3.8 GHz RF Downconversion Schematic
ALL
INDUCTORS
ARE 0302CS
SERIES FROM
COILCRAFT
RF
3.5nH
IF
L1
1.8pF
C2
1.2pF
C1
RF/IF
RF/IF
8
1
L2
1.5nH
C
100pF
AC
GND2
NC
ADL5350
7
2
4.7µF
VPOS
LOIN
LO
3V
6
3
100pF
3.8nH
2.2nH
100pF
GND1
RF
GND1
5
4
− f
LO
) to be
Rev. PrE | Page 20 of 24
Classic audio crossover filter design techniques can be applied
to help derive component values. However, some caution must
be applied when selecting component values. At high RF
frequencies, the board parasitics can significantly influence the
final optimum inductor and capacitor component selections.
Some empirical testing may be necessary to optimize the RF
and IF port filter networks. The performance of the circuit
depicted in Figure 63 is provided in Figure 64.
30
25
20
15
10
3500
5
0
Figure 64. Measured Performance for Circuit in Figure 63
Using Low-Side LO Injection and 800 MHz IF
3600
Preliminary Technical Data
RF FREQUENCY (MHz)
3700
IIP3
IP1dB
3800
GAIN
3900
4000
2
0
–2
–4
–6
–8
–10