CX20524 Mixed Signal Device for GSM and GPRS
Applications
Applications
• GSM handsets and modules (850/900/1800/1900 MHz)
• GPRS handsets and modules (850/900/1800/1900 MHz)
Features
• Supports multi-slot GPRS up to Class 12
• ΣΔ Analog-to-Digital Converters (ADCs) for digitization of
baseband receive signal
• Receive path PGA for AGC of received signal
• GMSK Digital Modulator
• Digital-to-Analog Converters (DACs) for analog conversion of
the GMSK modulator output
• Transmit power ramping and power level control
• Low noise voiceband ADC for direct interface to handset and
headset microphone
• Low noise voiceband DAC for direct interface to handset and
headset speaker
• Auxiliary 8-bit ADC for monitoring system signals
• 3 V/1.8 V SIM card interface
• Temperature sensor
• High speed asynchronous serial ports for interface to
Skyworks Baseband Processor device
• Low speed asynchronous serial port for power management
functions
• Voltage regulators for both internal (fixed voltage) and
system (programmable voltage) needs
• Low power operation
• Control circuit for multi-chemistry advanced battery charger
• Power-On Reset (POR) generation
• Over current-limiting
• Power On/Off control inputs
• CX20524-12: 160-pin FPBGA 12 mm x 12 mm package
• CX20524-13: 180-pin FPBGA 10 mm x 10 mm package
Description
The CX20524 Mixed Signal Device (MSD) is a highly integrated
device designed for use in multi-band Global System for
Mobile communications (GSM) and General Packet Radio
Service (GPRS) handsets. The MSD includes all the power
management, voice-band, mixed signal, and radio control
functions required in a GSM/GPRS handset and module.
In the receive path, the MSD digitizes the baseband In-
Phase/Quadrature (I/Q) inputs. Digital samples are then sent to
the Baseband Processor (BP) via the Rx serial interface. The
receive path features a programmable gain amplifier (PGA) for
Automatic Gain Control (AGC) of the receive signal.
In the transmit path, bursts of digital data are input to the MSD
over the control port. A Gaussian Minimum-Shift Keying
(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 MSD.
The CX20524 generates an analog signal to control the