STW81101AT datasheet(38/48 Pages) STMICROELECTRONICS

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Application information

STW81101

38/48

Application information

The STW81101 features three different alternately selectable bands: direct output (3.3 to

4.4GHz), divided by 2 (1.65 to 2.2GHz) and divided by 4 (850 to 1100MHz). To achieve a

suitable power level, a good matching network is necessary to adapt the output stage to a

Ω load. Moreover, since most commercial RF components have single-ended input and

output terminations, a differential to single-ended conversion may be required.

The different matching configurations shown below for each of the three bands are

suggested as a guideline when designing your own application board.

Inside the evaluation kit is the ADS design for each matching configuration suggested in this

chapter. The name of the corresponding ADS design is given in each figure.

The ADS designs provide only a first indication of the output stage matching, and should be

reworked according to the choices of layout, board substrate, components and so on.

The ADS designs of the evaluation boards are provided with a complete electromagnetic

modelling (board, components, and so on).

8.1

Direct output

If you do not need a differential to single conversion, you can match the output buffer of the

STW81101 in the simple way shown in

Figure 28. This illustrates a differential to single-

ended output network in the 3.3 - 4.4GHz range (MATCH_LC_LUMP_4G_DIFF.dsn).

Figure 28.

Differential/single-ended output network

(MATCH_LC_LUMP_4G_DIFF.dsn)

Since most discrete components for microwave applications are single-ended, you can

easily use one of the two outputs and terminate the other one to 50

Ω with a 3dB power loss.

100 ohm

50 ohm

100 ohm

5.5nH

10pF

50 ohm

10pF

Vcc

OUTP

OUTN

STW81101AT Datasheet(PDF) 38 Page - STMicroelectronics