ADL5811-EVALZ AD [Analog Devices], ADL5811-EVALZ Datasheet - Page 22

• Manufacturer Part Number: ADL5811-EVALZ
• Description: High IP3, 700 MHz to 2800 MHz, Double Balanced, Passive Mixer, IF Amplifier, and Wideband LO Amplifier
• Manufacturer: AD [Analog Devices]

ADL5811
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 59 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.
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 59.
ADL5811
mixer is designed to downconvert radio
VCC
AGND
C1
0.1µF
RFIN
BLK
C8
0.1µF
VPOS
C2
0.1µF
100pF
22pF
C6
RED
C7
470nH
470nH
VCC
L1
L2
VCC
10pF
C23
1
2
3
4
5
6
7
8
NC
RFCT
NC
RFIN
NC
NC
NC
NC
PAD
Figure 59. Basic Connections
910Ω
Rev. 0 | Page 22 of 28
R1
ADL5811
C20
10pF
VCC
120pF
120pF
C4
C3
BIAS RESISTOR SELECTION
An external resistor, R1, is 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.
VGS PROGRAMMING
The
voltages for optimizing mixer performance over the desired
frequency bands. The
Power conversion gain, input IP3, NF, and input P1dB can be
optimized, as shown in Figure 39 and Figure 40.
C19
10pF
VCC
TC4-1W+
ADL5811
DATA
C5
120pF
LOIP
LOIN
CLK
T1
NC
NC
NC
LE
C18
10pF
VCC
24
23
22
21
20
19
18
17
allows programmability for internal gate-to-source
R21
0Ω
R20
OPEN
LE
DATA
CLK
IFOP
IFON
22pF
C17
ADL5811
LOIP
defaults the VGS setting to 0.