AD8347ARU Analog Devices Inc, AD8347ARU Datasheet - Page 18

• Manufacturer Part Number: AD8347ARU
• Description: Quadrature Dmod 65MHz 28-Pin TSSOP
• Manufacturer: Analog Devices Inc

Specifications of AD8347ARU

• Package: 28TSSOP
• Device Type: Demodulator
• Maximum I/q Frequency: 65(Typ) MHz
• Modulation Type: Quadrature
• Typical Noise Figure: 11 dB
• Maximum Conversion Gain: 39.5(Typ) dB
• Rohs Status: RoHS non-compliant
• Function: Demodulator
• Lo Frequency: 800MHz ~ 2.7GHz
• Rf Frequency: 800MHz ~ 2.7GHz
• P1db: -30dBm
• Gain: 39.5dB
• Noise Figure: 11dB
• Current - Supply: 80mA
• Voltage - Supply: 2.7 V ~ 5.5 V
• Package / Case: 28-TSSOP

AD8347
APPLICATIONS
BASIC CONNECTIONS
The basic connections for operating the AD8347 are shown in
Figure 46. The device is powered through three power supply
pins: VPS1, VPS2, and VPS3. These pins supply current to
different parts of the overall circuit. VPS1 and VPS2 power the
local oscillator (LO) and RF sections, respectively, while VPS3
powers the baseband amplifiers. Connect all of these pins to the
same supply voltage; however, separately decouple each pin
using two capacitors. 100 pF and 0.1 μF capacitors are
recommended, though values close to these can be used.
Use a supply voltage in the range 2.7 V to 5.5 V. The quiescent
current is 64 mA when operating from a 5 V supply. By pulling
the ENBL pin low, the device goes into its power-down mode.
The power-down current is 400 μA when operating on a 5 V
supply and 80 μA on a 2.7 V supply.
Like the supply pins, the individual sections of the circuit are
separately grounded. COM1, COM2, and COM3 provide
ground for the LO, RF, and baseband sections, respectively.
Connect all of these pins to the same low impedance ground.
0.8GHz–2.7GHz
(AGC MODE)
0dBm MAX
RF INPUT
R1
200Ω
100pF
100pF
C1
C2
0.1μF
C6
ENBL
VGIN
RFIN
RFIP
100pF
VPS1
C5
15
10
11
17
2
0.1μF
C7
INTERFACE
CONTROL
VPS2
GAIN
100pF
AD8347
(2.7V–5.5V)
C8
CELL
BIAS
+V
12
0.1μF
S
C9
VDT1
DET 1
VPS3
100pF
20
C10
VAGC
21
19
VREF
VDT2
C15
0.1μF
DET 2
14
18
VREF
Figure 46. Basic Connections
C16
0.1μF
QMXO
IMXO
Rev. A | Page 18 of 28
22
8
1V BIAS (VREF)
1V BIAS (VREF)
(AGC MODE)
(AGC MODE)
13
16
24mV p-p
24mV p-p
IOFS
QOFS
C14
0.1μF
RF INPUT AND MATCHING
The RF input signal should be ac-coupled into the RFIP pin and
RFIN should be ac-coupled to ground. To improve broadband
matching to a 50 Ω source, a 200 Ω resistor can be connected
from the signal side of the RFIP coupling capacitor to ground.
LO DRIVE INTERFACE
For optimum performance, the LO inputs, LOIN and LOIP,
should be driven differentially; the M/A-COM balun, ETC1-1-13
is recommended. Unless an ac-coupled transformer is used to
generate the differential LO, the inputs must be ac-coupled, as
shown in
source, connect a 200 Ω shunt resistor between LOIP and LOIN.
A LO drive level of −8 dBm is recommended. Figure 20 shows
the relationship between LO drive level, LO frequency, and
quadrature error for a typical device.
A single-ended drive is also possible as shown in
this slightly increases LO leakage. Apply the LO signal through
a coupling capacitor to LOIP, and ac-couple LOIN to ground.
Because the inputs are fully differential, the drive orientation
can be reversed. As in the case of the differential drive, a 200 Ω
resistor connected across LOIP and LOIN improves the match
to a 50 Ω source.
VREF
VREF
C13
0.1μF
SPLITTER
IAIN
PHASE
2
24
6
VCMO
QAIN
Figure 46. To improve broadband matching to a 50 Ω
IOPP
25
4
QOPP
VCMO
SPLITTER
PHASE
1
26
3
QOPN
IOPN
28
23
27
5
1
7
9
LOIN
LOIP
VCMO
COM3
COM2
COM3
COM1
100pF
100pF
200Ω
C3
C4
R17
ETC 1-1-13
(M/A-COM)
3
1
T1
760mV p-p
DIFFERENTIAL
0.8GHz–2.7GHz
760mV p-p
DIFFERENTIAL
(AGC MODE)
V
(AGC MODE)
V
CM
CM
4
5
LO INPUT
Figure 47
–8dBm
= 1V
= 1V
QOPN
QOPP
IOPP
IOPN
, but