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Cellular Phone Power Amplifier Module with Built-in High/Low Output Switching for
Japanese Market CDMA2000 1×WIN Products
CXG1207K
In today’s advanced information society, the cellular phone is not merely a device
just for voice communication, but is evolving to become a leading-edge tool that
handles video and music content as well. To get the maximum performance possible
from cellular phones, Sony has now developed the CXG1207K high/low output
switching power amplifier module that takes full advantage of the features of Sony’s
original device technologies.
This power amplifier supports CDMA2000 1×WIN products and obviates the need
for the output control DC/DC converter, which was previously used in terminal sets.
We hope that you will take advantage of this device in developing miniature high-performance
mobile terminals. |
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CXG1207K |
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* Obviates the need for a DC/DC converter
* Miniature form factor, high
efficiency, low distortion
* Low Rx band noise
* Miniature module
* Built-in temperature compensation
circuit |
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Power Amplifier Module that
Obviates the Need for a DC/DC
Converter |
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The CDMA method requires that the output
power be controlled during transmission.
Therefore, in addition to the high
output power mode, it is also desired that
a low output power mode be provided in
the CDMA portable terminal power amplifier.
In conventional power amplifiers,
a DC/DC converter is provided separately and power consumption is minimized in
low-power mode by switching the power
amplifier supply voltage. In contrast, the
CXG1207K provides a low output power
mode path that minimizes power consumption,
and controls power consumption
in low-power output mode by switching
the path with an internal switching
circuit. This allows the DC/DC converter
that has been included in these products
up to now to be removed from the design.
This mode switching is controlled by applying
a high or low-level voltage to the
power amplifier CTL pin. The current
consumption in low-power mode is on the
order of a few tens of µA. Furthermore,
this structure consisting of power amplifier
and switching circuit is integrated on
the same chip, making this a product that
takes advantage of the features of Sony’s
JPHEMT* device technology.
* JPHEMT: Junction Pseudomorphic High Electron
Mobility Transistor |
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Miniature Package, High
Efficiency, and Low Distortion |
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Sony developed miniature JPHEMT
devices with even lower gm and on-resistance
characteristics to achieve even
further miniaturization and higher performance
in this IC. This allowed Sony to
achieve an operating voltage of 3.5 V, an
output power of 28 dBm, and ACPR1 of
-50 dBc, and an efficiency of 39.5% in
high-power mode in this device. This performance
is equal to or better than that of
earlier power amplifiers that used an external
DC/DC converter. Furthermore,
even in low-power mode, this device
achieves an operating voltage of 3.5 V,
an output power of 13.6 dBm, and ACPR1
of -60 dBc, and an efficiency of 17%, and when the output power is 18.5 dBm, it
achieves an ACPR1 of -55 dBc and low
distortion. The module matching circuit is
based on Sony’s low-loss matching circuit
technology developed up to now, but
achieves even further improvements in
integration by adopting 0402 components
and by reducing the number of components
used. As a result, this device
achieves a mounting area of 4.5 mm
square, which corresponds to a reduction
of about 50% from earlier high/low output
switching power amplifier modules. |
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Low Rx Band Noise |
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Due to the excellent low noise characteristics
of JPHEMT, the CXG1207K achieves
the -140 dBm/Hz Rx band noise of the
industry’s top level. |
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Miniature Module |
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The CXG1207K is a miniature module
with a volume of only 0.03 cc (4.5 mm ×
4.5 mm × 1.35 mm). |
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Built-in Temperature Compensation
Circuit |
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The power amplifier bias current varies
widely with changes in temperature, and
that can result in a corresponding degradation
of device characteristics.
The
CXG1207K includes a built-in temperature
compensation circuit that controls the
bias current to the optimal for the temperature
as the temperature changes.
This minimizes
the degradation in device characteristics
at both high and low temperatures. |
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•••• Mr. SHIMADA••••
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To distinguish this new power
amplifier with built-in high/low
output switching function from
conventional power amplifiers, we
developed it based on the concept
of high added value. While we had
previously developed the
CXG1170K 6.2 mm square switchable
power amplifier, the new
CXG1207K features even further
miniaturization. Although we
faced many difficulties in developing
this sensitive power amplifier
with a built-in switching function,
I am sure that this new product will
contribute both to further miniaturization
and lower costs in cellular
phone products, and can fully
satisfy our customers’ needs. We
are committed to developing even
more high value added products
that will be easy to use for our customers
in the future. Keep your
eye on Sony for cellular phone
devices. |
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See
all articles with figures and tables.  |
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Vol.41 |
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