adl5354 Analog Devices, Inc., adl5354 Datasheet - Page 18

• Manufacturer Part Number: adl5354
• Description: 2200 Mhz To 2700 Mhz, Dual-balanced Mixer, Lo Buffer, If Amplifier, And Rf Balun
• Manufacturer: Analog Devices, Inc.

ADL5354
APPLICATIONS INFORMATION
BASIC CONNECTIONS
The ADL5354 mixer is designed to downconvert radio frequencies
(RF) primarily between 2200 MHz and 2700 MHz to lower inter-
mediate frequencies (IF) between 30 MHz and 450 MHz. Figure 52
depicts the basic connections of the mixer. It is recommended to
ac couple the RF and LO input ports to prevent nonzero dc
voltages from damaging the RF balun or LO input circuit. The
RFIN matching network consists of a series 1.5 pF capacitor and
a shunt 4.3 nH inductor to provide the optimized RF input return
loss for the desired frequency band.
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,
which matches many commonly used SAW filters without the
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need for a transformer. This results in a voltage conversion gain
that is approximately 6 dB higher than the power conversion gain,
as shown in Table 3. When a 50 Ω output impedance is needed,
use a 4:1 impedance transformer, as shown in Figure 52.
BIAS RESISTOR SELECTION
The IF bias resistors (R1 and R4) and LO bias resistors (R2 and R5)
are used to adjust the bias current of the integrated amplifiers at the
IF and LO terminals. It is necessary to have a sufficient amount
of current to bias both the internal IF and LO amplifiers to optimize
dc current vs. optimum IIP3 performance.
MIXER VGS CONTROL DAC
The ADL5354 features three logic control pins, VGS0 (Pin 24),
VGS1 (Pin 25), and VGS2 (Pin26), that allow programmability for
internal gate-to-source voltages for optimizing mixer performance
over desired frequency bands. The evaluation board defaults
VGS0, VGS1, and VGS2 to ground.