ADL5812-EVALZ AD [Analog Devices], ADL5812-EVALZ Datasheet - Page 22

• Manufacturer Part Number: ADL5812-EVALZ
• Description: Dual High IP3, 700 MHz to 2800 MHz, Double Balanced, Passive Mixer, IF Amplifier, and Wideband LO Amplifier
• Manufacturer: AD [Analog Devices]

ADL5812
APPLICATIONS INFORMATION
BASIC CONNECTIONS
The
frequencies (RF) primarily between 700 MHz and 2800 MHz
to lower intermediate frequencies (IF) between 30 MHz and
450 MHz. Figure 60 depicts the basic connections of the mixer.
It is recommended to ac couple RF and LO input ports to
prevent nonzero dc voltages from damaging the RF balun or LO
input circuit. A RFIN capacitor value of 22 pF is recommended.
IF PORT
The mixer differential IF interface requires pull-up choke inductors
to bias the open-collector outputs and to set the output match.
The shunting impedance of the choke inductors used to couple
dc current into the IF amplifier should be selected to provide
the desired output return loss.
ADL5812
mixer is designed to downconvert radio
VCC
VCC
RFIN2
RFIN1
C26
0.1µF
C1
0.1µF
C7
22pF
22pF
22pF
C24
C8
0.1µF
C6
C27
0.1µF
C2
0.1µF
22pF
C25
470nH
470nH
470nH
470nH
L3
L4
L1
L2
10
C2.3
10pF
1
2
3
4
5
6
7
8
9
RF1
RFCT1
NC
NC
NC
NC
NC
NC
RFCT2
RF2
PAD
910Ω
R2
910Ω
R1
Figure 60. Evaluation Board Schematic
ADL5812
120pF
120pF
120pF
120pF
C3
C4
C3
C4
Rev. 0 | Page 22 of 28
TC4-1W+
2
1
3
TC4-1W+
2
1
3
C30
120pF
T1
C5
120pF
T1
4
6
4
6
V1LO1
V2LO1
DATA
LOIP
LOIN
CLK
NC
NC
NC
LE
R22
0Ω
The real part of the output impedance is approximately 200 Ω,
as seen in Figure 31, which matches many commonly used SAW
filters without the need for a transformer. This results in a voltage
conversion gain that is approximately 6 dB higher than the power
conversion gain. When a 50 Ω output impedance is needed, use a
4:1 impedance transformer, as shown in Figure 60.
BIAS RESISTOR SELECTION
External resistors, R1 and R2, are used to adjust the bias current
of the integrated amplifier at the IF terminal. It is necessary to have
a sufficient amount of current to bias both the internal IF amplifier
to optimize dc current vs. optimum input IP3 performance.
Figure 42 and Figure 43 provide the reference for the bias
resistor selection when lower power consumption is considered at
the expense of conversion gain and input IP3 performance.
R23
OPEN
R21
0Ω
R20
OPEN
30
29
28
27
26
25
24
23
22
21
IFOP
IFON
IFON
IFOP
C15
10pF
LE
DATA
CLK
VCC
C16
22pF
22pF
C17
C11
10pF
C12
10pF
C13
10pF
C14
10pF
C18
10pF
C19
10pF
C20
10pF
VCC
VCC
VCC
VCC
VCC
VCC
VCC
RFIN2
AGND
BLK
VPOS
RED
VCC