ADL5375-05-EVALZ Analog Devices, ADL5375-05-EVALZ Datasheet - Page 25

• Manufacturer Part Number: ADL5375-05-EVALZ
• Description: RF Development Tools ADL5375-05 EVAL
• Manufacturer: Analog Devices
• Type: Modulators / Demodulatorsr
• Series: ADL5375r

Specifications of ADL5375-05-EVALZ

• Rohs: yes
• Product: Evaluation Boards
• Factory Pack Quantity: 1

Data Sheet
The value of this ac voltage swing limiting resistor is chosen
based on the desired ac voltage swing. Figure 60 shows the
relationship between the swing-limiting resistor and the peak-
to-peak ac swing that it produces when 50 Ω bias-setting
resistors are used. The differential peak-to-peak swing at the
modulator input is
Filtering
It is necessary to place an antialiasing filter between the DAC
and modulator to filter out Nyquist images, common mode
noise, and broadband DAC noise. The interface for setting up
the biasing and ac swing discussed in the Limiting the AC
Swing section lends itself well to the introduction of such a
filter. The filter can be inserted between the dc bias setting
resistors and the ac swing-limiting resistor. With this configuration,
the dc bias setting resistors and the signal scaling resistors
conveniently set the source and load resistances for the filter.
Figure 61 shows a third-order, Bessel low-pass filter with a 3 dB
frequency of 10 MHz. Matching input and output impedances
make the filter design easier, so the shunt resistor chosen is
100 Ω, producing an ac swing of 1 V p-p differential. The
frequency response of this filter is shown in Figure 62.
AD9122
Figure 60. Relationship Between the AC Swing-Limiting Resistor and the
IOUT1P
IOUT1N
IOUT2N
IOUT2
V
SIGNAL
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
Peak-to-Peak Voltage Swing with 50 Ω Bias-Setting Resistors
0
10
67
66
59
58
RBQN
RBQP

RBIN
RBIP
50Ω
50Ω
50Ω
50Ω
I
Figure 61. DAC Modulator Interface with
FS

10 MHz Third-Order, Bessel Filter
53.62pF
53.62pF


2
2


C1Q
C1I
R
R
100
B
B


771.1nH
771.1nH
771.1nH
771.1nH
R
R
LNQ
LPQ
LNI
LPI
L
L
R
L


350.1pF
350.1pF
(Ω)
C2Q
C2I
1000
RSLQ
100Ω
100Ω
RSLI
21
22
10
9
ADL5375-05
IBBP
IBBN
QBBN
QBBP
10000
Rev. B | Page 25 of 36
Complex IF Operation
The
IF (CIF), as well as a zero-IF signal (ZIF). The −1 dB bandwidth
of the
(Figure 63 and Figure 64 show the baseband frequency response
of the ADL5375, facilitating high CIF and providing sufficient
flat bandwidth for digital predistortion (DPD) algorithms).
Using a CIF places the LO leakage and the undesired sideband
outside the signal band at the modulator output where they can
be easily removed with a bandpass filter.
Figure 63.
–10
–20
–30
–40
–50
–60
ADL5375
Figure 62. Frequency Response for DAC Modulator Interface with
–1
–2
–3
–4
–5
–6
0
1
0
ADL5375
1
1
ADL5375-05
can be used with a DAC, generating a complex-
is approximately more than 400 MHz
10 MHz Third-Order Bessel Filter
GROUP DELAY
BASEBAND FREQUENCY (MHz)
Baseband Frequency Response Normalized to
FREQUENCY (MHz)
Response for 1 MHz
10
10
MAGNITUDE
100
ADL5375
100
36
30
24
18
12
6
0
1k