CXG1190EQ/AEQ |
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* Ultralow insertion loss: 0.9 dB in the
DCS/PCS Tx path and 0.65 dB in the
UMTS (Rx) path
* Dual low-pass filters:
Attenuation 30 dB typical
(GSM Tx 2fo, DCS/PCS Tx 2fo)
* Lead frame module that adopts a mold
array package
* Miniature low-height package:
LQFN-28P-01
(4.5 mm × 3.2 mm × 1.3 mm max.) |
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Switching Structure that
Achieves Low Insertion Loss |
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Insertion loss is an important index for
switch performance.
Switch modules using the conventional
LTCC* substrate adopted a structure in
which the frequency band was divided into
a low band (900 MHz band) and a high
band (1800/1900 MHz band) using a
diplexer, and after that, the path switches
were connected. (See figure 1.) The switch
structure adopted by Sony in these products
is the SP7T structure. A low-pass
filter is inserted in the GSM Tx path. (See
figure 2.) In the conventional LTCC module
structure, the insertion loss for all of
the paths was the sum of the diplexer and
the path switches themselves. As a result,
the overall loss was quite large.
In contrast, in the SP7T structure, only the
switch insertion loss occurs in the paths other than the GSM Tx path, thus achieving
low loss. For the GSM Tx path, the
SP7T + LPF structure can achieve lower
loss than the diplexer structure since a LPF
has smaller insertion loss than a diplexer.
Furthermore, these devices achieve
ultralow loss by using Sony’s unique
JPHEMT process. This contributes significantly
to reduced current consumption
during Tx and higher Rx sensitivity.
*: LTCC: Low temperature co-fired ceramic |
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Lead Frame Module |
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Conventional antenna switch modules
used in GSM terminals and other products
adopt a structure in which passive and
active elements, such as PIN diodes, are
mounted on an LTCC, FR-4 or similar
substrate. However, considering the
demands for multimode and multiband operation,
miniature low-height form factors,
and lower costs in recent cellular phone
products, it can easily be seen that it will
be difficult to achieve these using these
conventional structures. Sony’s response
to these issues was implemented using the
mold array package, which uses lead
frames, an existing package technology.
By adopting an existing package that uses
lead frames, Sony was able to assure the
pin count required for the increase in the
number of switches due to the use of
multimode and multiband operation. Furthermore,
this made further miniaturization
easy.
Another advantage was that it was possible
to keep to an absolute minimum the number of changes to the assembly process
in current manufacturing lines. This
contributes to lowering the cost of the devices.
Since handling is only required for
two simple components, an IC and a low-pass
filter, Sony was able to shorten the
development turn around time. Also, the
adoption of a package with a proven track
record in the market has the advantage that
customers can use these devices with confidence. |
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Miniature Low-Height Form
Factor |
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The mounting area was reduced by making
the two low-pass filters integrated in
the two Tx paths into one component
using LTCC technology. Also, etching
technology can be used to perform complicated
machining on the lead frame,
which plays the role of interface between
the internal components. That technology
is used for the connections for the internal
low-pass filters in these products. Furthermore,
Sony optimized the contact area
between the internal low-pass filter lands
and the lead frame and also optimized the
mold sealing thickness above the low-pass
filters, thus achieving a miniature low-height
form factor. |
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•••• Mr.NAGANO••••
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The CXG1190EQ/AEQ ICs could
only have been developed by
Sony, and were developed from
Sony’s unique perspective, a perspective
unknown at other companies.
These devices are already
earning an enthusiastic response
in the market. We are now planning
new products that deploy this
technology. Keep your eye on
Sony’s MMIC technologies! |
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See
all articles with figures and tables.  |
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Vol.38 |
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