AD8348ARU-REEL7 Analog Devices Inc, AD8348ARU-REEL7 Datasheet - Page 23

• Manufacturer Part Number: AD8348ARU-REEL7
• Description: IC QUADRATUR DEMOD 50MHZ 28TSSOP
• Manufacturer: Analog Devices Inc

Specifications of AD8348ARU-REEL7

• Rohs Status: RoHS non-compliant
• Function: Demodulator
• Lo Frequency: 100MHz ~ 2GHz
• Rf Frequency: 50MHz ~ 1GHz
• P1db: -22dBm
• Gain: 25.5dB
• Noise Figure: 10.75dB
• Current - Supply: 58mA
• Voltage - Supply: 2.7 V ~ 5.5 V
• Package / Case: 28-TSSOP

LO GENERATION
Analog Devices has a line of PLLs that can be used for
generating the LO signal. Table 4 lists the PLLs and their
maximum frequency and phase noise performance.
Table 4. ADI PLL Selection Table
ADI Model
ADF4001BRU
ADF4001BCP
ADF4110BRU
ADF4110BCP
ADF4111BRU
ADF4111BCP
ADF4112BRU
ADF4112BCP
ADF4116BRU
ADF4117BRU
ADF4118BRU
ADI also offers the ADF4360 fully integrated synthesizer and
VCO on a single chip that offers differential outputs for driving
the local oscillator input of the AD8348. This means that the user
can eliminate the use of a balun for single-ended-to-differential
conversions. The ADF4360 comes as a family of chips with six
operating frequency ranges. One can be chosen depending on
the local oscillator frequency required. Table 5 shows the
options available.
Table 5. ADF4360 Family Operating Frequencies
ADI Model
ADF4360-1
ADF4360-2
ADF4360-3
ADF4360-4
ADF4360-5
ADF4360-6
ADF4360-7
EVALUATION BOARD
Figure 60 shows the schematic for the AD8348 evaluation
board. Note that uninstalled components are indicated with the
OPEN designation. The board is powered by a single supply in
the range of 2.7 V to 5.5 V. Table 6 details the various configu-
ration options of the evaluation board. Table 7 shows the various
jumper configurations for operating the evaluation board with
different signal paths.
Power to operate the board can be fed to a single V
located near the LO input port at the top of the evaluation
board. A GND test point is conveniently provided next to the
V
S
test point for the return path.
Output Frequency Range (MHz)
2150 to 2450
1800 to 2150
1550 to 1950
1400 to 1800
1150 to 1400
1000 to 1250
Lower frequencies set by external L
Frequency F
(MHz)
165
165
550
550
1200
1200
3000
3000
550
1200
3000
IN
@ 1 kHz ΦN
dBc/Hz,
−99
−99
−91
−91
−78
−78
−86
−86
−89
−87
−90
200 kHz PFD
S
test point
Rev. A | Page 23 of 28
The device is enabled by moving Switch SW11 (at the bottom left
of the evaluation board) to the ENBL position. The device is
disabled by moving SW11 to the DENBL position. If desired, the
device can be enabled and disabled from an external source that
can be fed into the ENBL SMA connector or the VENB test point,
in which case SW11 should be placed in the DENBL position.
The IF and MX inputs are selected via SW12. The switch should
be moved in the direction of the desired input.
Gain Control
For convenience, a potentiometer, R15, is provided to allow for
changes in gain without the need for an additional dc voltage
source. To use the potentiometer, the SW13 switch must be set
to the POT position. Alternatively, an external voltage applied
to either the test point or SMA connector labeled VGIN can set
the gain. SW13 must be set to the EXT position when an
external gain control voltage is used.
LO Input
The local oscillator signal should be fed to the SMA Connector
J21. This port is terminated in 50 Ω. The acceptable LO power
input range is from −12 dBm to 0 dBm and must be at a
frequency double that of the IF/MX frequency. Remember that
the AD8348 uses a 2:1 frequency divider in the LO path to
generate the internally required quadrature-phase-related LO
signals.
IF Input
The IF input should be fed into the SMA connector IFIP. The
VGA must be enabled when this port is used (SW12 in the IF
position). When this IF input is chosen, the signal path includes
a minimum-loss attenuator to transform a 50 Ω input source to
the 200 Ω source impedance level for which the VGA was
designed. This pad provides a very broadband input match at
the expense of an 11.46 dB power attenuation in the input path.
It is very important to take this into account when measuring
the noise and distortion performance of the unmodified board
using the IFIP input; the apparent noise figure will be degraded
by 11.46 dB, and the apparent IIP3 will be 11.46 dB higher than
actual. If full weak-signal performance is desired from the
evaluation board, the attenuator (comprising R31 and R32)
should be removed and replaced with a low-loss RF transformer
providing the desired 4:1 impedance ratio. When a transformer
is used, IFIN should be ac-coupled to ground and not driven
differentially with IFIP.
MX Input
The evaluation board is by default set for a differential MX drive
through a balun (T41) from a single-ended source fed into the
MXIP SMA connector. When the MX inputs are used, the
internal VGA is bypassed. To change to a differential driving
source, T41 should be removed along with Resistor R42. The
0 Ω R43 and R44 resistors should be installed in place of T41 to
bridge the gap between the input traces. This presents a nominal
AD8348