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Analog-to-Digital Converters (ADCs) for digitization of
baseband receive signal
Receive path Programmable Gain Amplifier (PGA) for
Automatic Gain Control (AGC) of received signal
Burst Store Random Access Memory (RAM) for storage of
transmit data bursts
Gaussian Minimum-Shift Keying (GMSK) Digital Modulator
for modulation of Burst Store contents
Digital-to-Analog Converters (DACs) for analog conversion
of the GMSK modulator output
Transmit power ramping and power level control
Low noise, voice-band ADC for interface to handset
microphone
Low noise voice-band DAC for interface to handset
speaker
Auxiliary 8-bit ADC for monitoring system signals such as
battery voltage
High speed serial ports for interface to a Baseband
Processor device
Internal power supply regulation from a single input
voltage
Temperature Sensor for system thermal monitoring
104-pin 10 mm x 10 mm FPBGA package
Introduction
The CX20505-14 Integrated Analog (IA) is a highly integrated
device designed for use in multi-band GSM and GPRS
handsets. This device implements all the voice-band, mixed
signal, and radio control functions in a GSM/GPRS handset.
In the receive path, the CX20505-14 digitizes the baseband
In-Phase/Quadrature (I/Q) input, and outputs the digital
samples on the device receive port. The receive path features
a PGA for AGC of the receive signal.
In the transmit path, bursts of digital data are input to the
device over the control port. The GMSK modulator generates
modulated I and Q waveforms from the input data. The I and Q
waveforms are converted into analog waveforms and output
from the device.
The CX20505-14 generates an analog signal to control the
handset Power Amplifier (PA) output level. The signal is then
input to the Power Amplifier Control (PAC) circuit.
The voice-band Codec section provides an interface to a 32
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handset speaker and microphone. Line In/Out signals are also
available for interfacing to audio accessories such as a headset
or car kit.
The device operates directly from a single cell, 3.6 V Li Ion
battery with no external regulation required. The device
features Low Drop Out (LDO) voltage regulators that generate
the required device power supplies from the battery input.
A typical CX20505-14 application in a handset design is shown
in Figure 1. The device is packaged in a compact, 104-pin
(10mm x 10mm) Fine Pitch Ball Grid Array (FPBGA) see
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FEATURES
103186A
Skyworks Solutions, Inc., Proprietary and Confidential
[781] 376-3000錚ax [781] 376-3100錚ales@skyworksinc.com錚ww.skyworksinc.com
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September 22, 2003
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