ADL5324ARKZ-R7 datasheet(15/20 Pages) AD

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Data Sheet

ADL5324

Rev. 0 | Page 15 of 20

MATCHING PROCEDURE

The ADL5324 is designed to achieve excellent gain and OIP3

performance. To achieve this, both input and output matching

networks must present specific impedance to the device. The

matching components listed in Table 7 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 ADL5324 for optimum OIP3 and

gain at 750 MHz, use the following steps:

1. Install the recommended tuning components for an 869 MHz

to 970 MHz tuning band, but do not install C1 and C2.

2. Connect the evaluation board to a vector network analyzer

so that input and output return loss can be viewed simulta-

neously.

3. 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 satis-

factory 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.

4. 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.

Fixed Load Pull

Freq = 2.1400 GHz

ZSource_2nd (Ohms) : 50.00 + j 0.00

ZSource_3rd (Ohms) : 50.00 + j 0.00

max = 16.06 dB

2.97 – j 2.70 Ohms

10 contours,

0.50 dB step

(11.50 to 16.00 dB)

Ip3

max = 44.18 dBm

9.44 + j 9.65 Ohms

10 contours,

1.00 dBm step

(35.00 to 44.00 dBm)

Specs: OFF

Load

Label:

ADL5324_2P14_LP7

Figure 36. Load-Pull Contours, 2140 MHz

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

max = 13.83 dB

4.27 – j 1.99 Ohms

10 contours,

0.50 dB step

(9.00 to 13.50 dB)

Ip3

max = 45.19 dBm

2.84 + j 5.89 Ohms

10 contours,

1.00 dBm step

(36.00 to 45.00 dBm)

Specs: OFF

Load

Label:

ADL5324_2p63ghZ_LP3

26.37 + j30.90

Figure 37. Load-Pull Contours, 2600 MHz

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