GaAs MMIC Low Noise Amplifier SOIC-8 Platform

Rev. V3

Application Note

M540

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M/A-COM Technology Solutions Inc. and its affiliates reserve the right to make

changes to the product(s) or information contained herein without notice.

MAAM12022 over the 1.2 - 1.6 GHz

Frequency Range

Both the MAAM12021 and MAAM12022 can be tuned to

cover the 1.2 - 1.6 GHz frequency range with the addition

of some external matching networks. The matching net-

works to accomplish this for both LNAs are shown sche-

matically in Figure 13. Distributed matching is shown,

although an equivalent lumped element approach would

also suffice. The gain performance of the MAAM12022

when matched using the distributed topology of Figure

13 is shown in Figure 14; the nose figure performance is

shown in Figure 15. For this LNA, the external matching

has even improved the noise figure in the original fre-

quency range, but at the expense of input match in that

range.

External matching networks can be used to extend the

frequency range of all the LNAs in this product platform.

In fact, the AM50-0002 has been designed to require an

external matching network to achieve a good match and

minimum noise figure performance at the intended fre-

quency. In some instances, as shown above for the

MAAM12022, it may be possible to improve the noise

figure of the LNA at the expense of input match. It is

also possible to combine external tuning with the bias

options described in the previous subsection to create

additional performance possibilities with these LNAs.

AM50-0001 as A Transmit Driver

Amplifier

The AM50-0001 was originally designed for the cellular

industry as a high dynamic range, base station receive

amplifier with a noise figure of 1.5 dB and output IP3 of

the same current drain of 50 mA, the AM50-0001 can put

out more than +20 dBm of power as shown in the output

power versus input power curve of Figure 16.

Performance Data & Recommended

Board Layouts

To facilitate ease of evaluation by the customer for either

alternative matching networks or to simulate system per-

formance directly, de-embedded S-parameter and noise

parameter data is available for all members of the GaAs

MMIC LNA family discussed in this application note.

These data files are in DOS ASCII Touchstone® format.

Please note that not all biases of each device are avail-

able; please consult the factory. Additional performance

data, which is discussed in the product applications sec-

tions, is also available.

Another avenue for evaluating these MMIC LNAs is by

mounting the SOIC-8 to an FR4 board. A typical sample

board layout is shown in Figure 17. This sample board

accommodates the AM50-0002 and includes the recom-

mended external input matching network for 1.575 GHz

operation. A similar sample board layout accommodates

the other six LNAs in this product platform. The .dxf files

for these layouts are available from the factory. Addition-

ally, these sample boards, as well as LNA samples, can

be ordered from the factory.