CX20470 Datasheet, PDF (1/18 Pages) Skyworks Solutions Inc. – CDMA Baseband Analog Processor

CX20470
CDMA Baseband Analog Processor
The CX20470 is a dual-mode Baseband Analog Processor (BAP) for use in Code
Division Multiple Access (CDMA) and Frequency Modulated (FM) portable
telephones. The device is designed to interface between the RF section and the
digital processing circuitry of the telephone. The CX20470 CDMA BAP includes all
of the circuitry needed to support baseband signal processing and conversions
between analog and digital signals in a dual mode CDMA and FM phone.
The receive section accepts analog baseband in-phase (I) and quadrature-phase
(Q) signals, performs channel selection lowpass filtering, and converts the analog
baseband signals into digital signals. The transmit section function provides the
reverse conversions for digital input signals. In addition, the transmit section also
accepts differential analog I and Q signals from baseband.
The CX20470 CDMA BAP also includes digital and Phase Locked Loop (PLL) clock
synthesis for 19.2 MHz, 19.68 MHz, and 19.8 MHz system clocks, general purpose
Analog-to-Digital (A/D) conversions for battery and signal strength monitoring, and
two PLL synthesizers
The CX20470 CDMA BAP integrates an audio Coder/Decoder (CODEC) that
provides signal translation between an analog voice band signal and a Pulse Code
Modulation (PCM) digital signal. The CODEC is designed to perform the transmit
encoding A/D conversion, together with transmit and receive filtering, for voice-
band communication systems. The CODEC’s audio interface consists of 3
microphone inputs, 3 audio speaker outputs, and DTMF/tone(s)/ring/side tone
generation. The CODEC operation and configuration registers can be programmed
by a microcontroller via an Inter-Integrated Circuit (I²C) compatible or 3-wire bus
interface at any time. The CODEC also integrates the microphone amplifier and
speaker post amplifier on-chip. The post amplifier is capable of driving a 32 Ω load
directly.
The device is available in 100-pin µBGA and 56-pin Land Grid Array (LGA)
packages:
• 100-pin µBGA – CDMA, FM, dual VHF synthesizers, 7-input monitor ADC,
audio CODEC
• 56-pin LGA – CDMA, single VHF synthesizer, 2-input monitor ADC.
The device package pinout for each of these are shown in Figures 1 and 2. A
general block diagram of the CX20470 BAP is shown in Figure 3.
Distinguishing Features
• Dual mode for CDMA and FM operation.
• Receive signal path includes:
− Separate CDMA, and FM filters and ADCs
− Offset control loop
• Transmit signal path includes:
− Configurable input interface to either digital or
analog I/Q signals from the baseband modem
− Selectable conversion of digital I-Q data to analog
signals
− Separate CDMA filters and FM filters
• Two VHF PLL synthesizers:
− Programmable charge pump current
− Lock detector output
− Operate in concert with CDMA mode operation
• System clock generation and support includes:
− 19.2/19/68/19.8 MHz system clock support
− External CHIPx8 clocks (input to BAP)
− TCXO/4 and CHIPx8 clocks powerdown capability
• Audio CODEC includes:
− 14-bit linear CODEC with on-chip filters meet ITU-T
G.712 requirements
− Switchable 3 microphone inputs with pre-amplifier
gain control from –4 to 40 dB in 2 dB steps
− Switchable 3 speaker outputs with programmable
post-amplifiers from 0 to –30 dB in 2 dB steps, and
capable of driving 32 Ω load directly.
− Programmable frequency and gain for
DTMF/Tone(s)/Ring/Sidetone generation
− Separate ringer output with gain control
• 8-bit general purpose ADC with 7 input channels
• Independent mode and operation controls for BAP
and CODEC functions
• Low power consumption in all operation modes
• Baseband modem interface compatibility includes:
− MSM2300/MSM3000
− MSM3100
• Single supply voltage from 2.7 V to 3.6 V
• Operating temperature of –40 °C to +85
• Package options include:
− 100-pin µBGA
− 56-pin LGA
Applications
• Cellular and Advanced Mobile Phone System (AMPS)
band phones
• Dual band PCS/cellular CDMA
• Dual mode/dual band
Data Sheet
Skyworks – Preliminary
Proprietary Information and Specifications are Subject to Change
Order No. 101106A
August 24, 2000