ADL5324 AD [Analog Devices], ADL5324 Datasheet - Page 15

• Manufacturer Part Number: ADL5324
• Description: 400 MHz to 4000 MHz
• Manufacturer: AD [Analog Devices]

Data Sheet
MATCHING PROCEDURE
The
performance. To achieve this, both input and output matching
networks must present specific impedance to the device. The
matching components listed in Table 6 were chosen to provide
−10 dB input return loss while maximizing OIP3.
The load-pull plots (see Figure 36 and Figure 37) show the load
impedance points on the Smith chart where optimum OIP3, gain,
and output power can be achieved. These load impedance values
(that is, the impedance that the device sees when looking into
the output matching network) are listed in Table 8 and Table 9
for maximum gain and maximum OIP3, respectively. The contours
show how each parameter degrades as it is moved away from
the optimum point.
From the data shown in Table 8 and Table 9, it becomes clear that
maximum gain and maximum OIP3 do not occur at the same
impedance. This can also be seen on the load-pull contours in
Figure 36 and Figure 37. Thus, output matching generally involves
compromising between gain and OIP3. In addition, the load-
pull plots demonstrate that the quality of the output impedance
match must be compromised to optimize gain and/or OIP3. In
most applications where line lengths are short and where the
next device in the signal chain presents a low input return loss,
compromising on the output match is acceptable.
To adjust the output match for operation at a different frequency,
or if a different trade-off between OIP3, gain, and output
impedance is desired, a four-step procedure is recommended.
For example, to optimize the
gain at 750 MHz, use the following steps:
1.
2.
3.
ADL5324
Install the recommended tuning components for an 869 MHz
to 970 MHz tuning band, but do not install C1 and C2.
Connect the evaluation board to a vector network analyzer
so that input and output return loss can be viewed
simultaneously.
Starting with the recommended values and positions for
C1 and C2, adjust the positions of these capacitors along the
transmission line until the return loss and gain are acceptable.
In this case, push-down capacitors mounted on small sticks
can be used as an alternative to soldering. If moving the
component positions does not yield satisfactory results,
then increase or decrease the values of C1 and C2 (in this
case, the values are most likely increased because the user
is tuning for a lower frequency.
is designed to achieve excellent gain and OIP3
ADL5324
for optimum OIP3 and
Rev. B | Page 15 of 20
4.
Table 8. Load Conditions for Gain
Frequency (MHz)
2140
2630
Table 9. Load Conditions for OIP3
Frequency (MHz)
2140
2630
Fixed Load Pull
Freq = 2.6300 GHz
ZSource (Ohms) : 49.84 + j 4.33
ZSource_2nd (Ohms) : 37.79 + j 3.28
ZSource_3rd (Ohms) : 39.74 + j10.00
Gt
10 contours,
Ip3
10 contours,
Specs: OFF
(36.00 to 45.00 dBm)
Fixed Load Pull
Freq = 2.1400 GHz
ZSource_2nd (Ohms) : 50.00 + j 0.00
ZSource_3rd (Ohms) : 50.00 + j 0.00
Gt
10 contours,
Ip3
10 contours,
Specs: OFF
(9.00 to 13.50 dB)
(35.00 to 44.00 dBm)
(11.50 to 16.00 dB)
at
at
at
at
Repeat Step 3 as necessary. Once the desired gain and return
loss are realized, measure OIP3. Most likely, it will be
necessary to go back and forth between return loss/gain and
OIP3 measurements (probably compromising most on output
return loss) until an acceptable compromise is achieved.
4.27 – j 1.99 Ohms
2.84 + j 5.89 Ohms
2.97 – j 2.70 Ohms
9.44 + j 9.65 Ohms
max = 13.83 dB
max = 16.06 dB
0.50 dB step
max = 45.19 dBm
1.00 dBm step
0.50 dB step
max = 44.18 dBm
1.00 dBm step
Figure 36. Load-Pull Contours, 2140 MHz
Figure 37. Load-Pull Contours, 2600 MHz
ΓLoad
(Magnitude)
0.888
0.0843
ΓLoad
(Magnitude)
0.654
0.894
26.37 + j30.90
MAX
MAX
Load
ΓLoad (°)
+163.28
+166.52
Load
ΓLoad (°)
−173.55
−175.41
Label:
ADL5324_2p63ghZ_LP3
Label:
ADL5324_2P14_LP7
IP3
44.18
45.19
ADL5324
Gain
16.1
13.83
MAX
MAX
(dBm)
(dB)