Electrical Characterization of Packages for Use with GaAs

MMIC Amplifiers

Rev. V4

Application Note

M542

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Figure 1. Probeable Ceramic Substrate

Figure 2. Fixtured MAAM71200-H1

To de-embed this “test fixture,” a set of through-

reflect-line (TRL) standards was employed.

A

“zero-length” through, a short, and two delay lines

were fabricated. These standards, shown in Figure

3, are used with the common TRL de-embedding

algorithm.

This allows any measurement made

with the probeable ceramic substrates to be de-

embedded to yield data for only the DUT with con-

necting bonds.

Bond wires can also be de-

embedded by first characterizing and modeling

them using this same “probeable ceramic” tech-

nique. For this work, multiple bond wire and ribbon

lengths were characterized to generate fully scal-

able bond models.

Figure 3. TRL Calibration Standards

To

demonstrate

the

package

characterization

method, the evaluation of a standard Kyocera 8-

lead ceramic flat pack will be examined. Figure 4

shows how one feedthrough structure in the wall of

this package was tested. Package leads were cut

close to the package body, and the ceramic sub-

strates were mounted flush to the package ports.

Two short 3-mil wide gold ribbons bond the sub-

strates to the package.

Similarly, sealed packages with leads internally

terminated with 50 ohm chip resistors were tested

to determine the cross-coupling between opposite

and adjacent leads.

Through-lines within sealed

packages were also measured. With this data, the

true electrical performance of the package was de-

termined and models for the feedtrhough and cou-

pling were developed.

Figure 4. Fixtured Feedthrough

This information allows the identification of an ap-

propriate package for existing MMIC products and

provides an accurate model for incorporating pack-

age effects into future design work.