CXA3117 Datasheet, PDF (1/2 Pages) Sony Corporation – Achieving Low Power and High Speed in Paging System IF IC

Achieving Low Power and High Speed in Paging System
IF IC for High-Speed Paging Systems
CXA3117N, CXA3176N, CXA3179N
High-speed paging systems that employ M-ary signals are about to
enter service.
Sony strongly supports this new service with three IF ICs: the
CXA3117N, the CXA3176N, and the CXA3179N.
The CXA3117N, which adopts a comparator system that does not re-
quire an A/D converter, and the CXA3179N, which supports AFC, can
contribute significantly to parts count reductions and thus reduced pro-
duction costs.
The CXA3176N implements a high-speed paging system that uses an
A/D converter and supports AFC.
s Low current consumption
(CXA3117N/CXA3176N/
CXA3179N)
s No A/D converter required in
comparator system adopted
(CXA3117N/CXA3179N)
s AFC support (CXA3176N/
CXA3179N)
s RSSI dynamic range: 70 dB,
detector output: 600 mVrms
(CXA3176N)
Low Current Consumption
At the same time as incorporating both
a comparator that supports M-ary high-
speed paging systems and a variable cut-
off bit rate filter that responds to
changes in the data rate, these products
achieve a current consumption that is
20% lower than that of the POCSAG
system based CXA1484AN.
VOICE
I am convinced that the compara-
tor system proposed by Sony and
used in the CXA3117N and
CXA3179N will become the main-
stream in M-ary paging systems in
the future. I think that once you
have tried these devices you will
appreciate the validity of this
system. Please look into these
products for use in your systems.
Comparator System
does not Require an A/D
Converter
In the first generation of M-ary high-
speed paging systems, the output of the
detector was input to an A/D
converter to acquire the two bits of data
in the signal. However, the comparator-
based system used in these products
uses three comparators to perform a
signal-processing operation equivalent
to A/D conversion and acquire the two
bits of digital data. This allows circuits
that were previously implemented as
two chips, an IF IC and an A/D
converter, to be implemented in a single
IF IC.
AFC Support
A circuit that cancels the frequency off-
set of the receiver oscillator is required
in 900-MHz band paging systems and
in narrow band systems. The
CXA3176N and CXA3179N include an
offset detection circuit that uses S-curve
characteristics, and implement an AFC
circuit by feeding back the output of this
circuit to the first oscillator.
RSSI Dynamic Range: 70 dB,
Detector Output: 600 mVrms
In addition to providing the extremely
wide RSSI dynamic range of 70 dB, the
CXA3176N also features excellent tem-
perature characteristics. These allow the
CXA3176N to be used in a wide range
of applications. Furthermore, the
CXA3176N detector output operating
point is automatically adjusted to
achieve an optimal dynamic range in
response to the supply voltage.