AD8343ARUZ Analog Devices Inc, AD8343ARUZ Datasheet - Page 24

• Manufacturer Part Number: AD8343ARUZ
• Description: IC MIXER ACTIVE HI-IP3 14-TSSOP
• Manufacturer: Analog Devices Inc
• Series: AD8343r

Specifications of AD8343ARUZ

• Frequency: 0Hz ~ 2.5GHz
• Rf Type: Cellular, WLAN
• Number Of Mixers: 1
• Gain: 7dB
• Noise Figure: 14dB
• Secondary Attributes: Up/Down Converter
• Current - Supply: 60mA
• Voltage - Supply: 4.5 V ~ 5.5 V
• Package / Case: 14-TSSOP (0.173", 4.40mm Width)
• Supply Voltage Range: 4.5V To 5.5V
• Rf Ic Case Style: TSSOP
• No. Of Pins: 14
• Operating Temperature Range: -40°C To +85°C
• Msl: MSL 1 - Unlimited
• Ic Function: IF Subsystem
• Termination Type: SMD
• Supply Voltage Min: 4.5V
• Rohs Compliant: Yes
• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Industrial
• Filter Terminals: SMD
• Digital Ic Case Style: TSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

AD8343
This theoretical design is important because it establishes the
basic topology and the initial matching value for the network.
The theoretical value of 2.9 pF for the initial matching compo-
nent is not available in standard capacitor values, so a 3.0 pF is
placed in the first shunt-matching location. This value can
prove to be too large, causing an overshoot of the 50 Ω real
impedance circle, or too small, causing the opposite effect.
Always keep in mind that this is a measure of differential
impedance. The value of the capacitor must be modified to
achieve the desired 50 Ω real impedance.
However, it occasionally happens that the inserted shunt
capacitor moves the impedance in completely unexpected
and undesired ways. This is almost always an indication that
the reference plane was improperly extended for the measure-
ment. Readjust the reference planes and attempt the shunt
capacitor match with another calculated value.
When a differential impedance of 50 Ω (real part) is achieved,
the board must be powered down and then another short is
placed on the board in preparation for resetting the port exten-
sions to a new reference plane location. Place this short where
the next series components are expected to be added, and it is
important that both Port 1 and Port 2 be extended to this point
on the board.
Another differential measurement must be taken at this point
to establish the starting impedance value for the next matching
component. Note that if 50 Ω PCB traces of finite length are
used to connect pads, the impedance experiences an angular
rotation to another location on the Smith Chart as indicated in
Figure 68.
Figure 67. Theoretical Design of Matching Network
0.2
0.5
1
2.9pF SHUNT CAPACITOR
2
1.0
2.0
5.0
Rev. B | Page 24 of 32
With the reference plane extended to the location of the series
matching components, it is now necessary to readjust the shunt
capacitance value to achieve the desired 50 Ω real impedance.
However, this rotation is not very noticeable if the board traces
are fairly short or the application frequency is low.
As before, calculate the series capacitance value required to
move in the direction shown as step two in Figure 67. Choose
the nearest standard component remembering to perform the
differential conversion, and install on the board. Again, if any
unexpected impedance transformations occur the reference
planes were probably extended incorrectly making it necessary
to readjust these planes.
This value of series capacitance adjusts to obtain the desired
value of differential impedance.
These steps apply to any of the previously discussed matching
topologies suitable for the AD8343. Also, if a target impedance
other than 50 Ω is required, simply calculate and adjust the
components to obtain the desired load impedance.
If the matching network topology requires a differential shunt
inductor between the inputs, it is necessary to place a series
blocking capacitor of low reactance in series with the inductor
to avoid creating a low resistance dc path between the input
terminals of the AD8343. Failure to heed this warning results
in very poor LO-output isolation.
Transfer the Matching Network to the Final Design
On the B side of the AD8343 evaluation board, install the matching
network and the input balun. Install the same output network as
used for the work on the A side, then power up the board and
measure the input return loss at the RF input connector on the
board. Strictly speaking, the above procedure (if carried out
accurately) for matching the AD8343 obtains the best conver-
sion gain. This differs materially from the condition that results
in best return loss at the board’s input if the balun is lossy.
0.2
Figure 68. Effect of 50 Ω PCB Trace on 50 Ω Real Impedance Load
0.5
0.2
0.5
FREQUENCY = 1.8GHz
3.3pF SHUNT CAPACITOR
1.0
1.0
5mm 50Ω TRACE
2.0
0
2.0
5.0
5.0