Four-Channel, 80 MSPS Digital
Receive Signal Processor (RSP)
a
AD6624
The AD6624 is part of Analog Devices’ SoftCell® multicarrier
transceiver chipset designed for compatibility with Analog
Devices’ family of high sample rate IF sampling ADCs (AD6640/
AD6644 12- and 14-bit). The SoftCell receiver comprises a
digital receiver capable of digitizing an entire spectrum of
carriers and digitally selecting the carrier of interest for tuning
and channel selection. This architecture eliminates redundant
radios in wireless base station applications.
FEATURES
80 MSPS Wide Band Inputs (14 Linear Bits Plus 3 RSSI)
Dual High Speed Data Input Ports
Four Independent Digital Receivers in Single Package
Digital Resampling for Noninteger Decimation Rates
Programmable Decimating FIR Filters
Programmable Attenuator Control for Clip Prevention
and External Gain Ranging via Level Indicator
Flexible Control for Multicarrier and Phased Array
3.3 V I/O, 2.5 V CMOS Core
User-Configurable Built-In Self-Test (BIST) Capability
JTAG Boundary Scan
High dynamic range decimation filters offer a wide range of
decimation rates. The RAM-based architecture allows easy
reconfiguration for multimode applications.
The decimating filters remove unwanted signals and noise from
the channel of interest. When the channel of interest occupies less
bandwidth than the input signal, this rejection of out-of-band
noise is called “processing gain.” By using large decimation
factors, this “processing gain” can improve the SNR of the
ADC by 30 dB or more. In addition, the programmable RAM
coefficient filter allows antialiasing, matched filtering, and
static equalization functions to be combined in a single, cost-
effective filter.
APPLICATIONS
Multicarrier, Multimode Digital Receivers GSM, IS136,
EDGE, PHS, IS95
Micro and Pico Cell Systems
Wireless Local Loop
Smart Antenna Systems
Software Radios
In-Building Wireless Telephony
The AD6624 is compatible with standard ADC converters such
as the AD664x, AD9042, AD943x, and the AD922x families of
data converters. The AD6624 is also compatible with the AD6600
Diversity ADC, providing a cost and size reduction path.
PRODUCT DESCRIPTION
The AD6624 is a four-channel (quad) digital receive signal
processor (RSP) with four cascaded signal-processing elements:
a frequency translator, two fixed-coefficient decimating filters,
and a programmable-coefficient decimating filter.
FUNCTIONAL BLOCK DIAGRAM
16 BITS
18 BITS
20 BITS
24 BITS
SDIN[3:0]
RAM
COEFFICIENT
FILTER
INA[13:0]
EXPA[2:0]
rCIC2
CH A
CH B
CH C
CH D
NCO
NCO
NCO
NCO
CIC5
CIC5
CIC5
CIC5
RESAMPLER
SDO[3:0]
DR[3:0]
IENA
LIA-A
LIA-B
SDFS[3:0]
RAM
COEFFICIENT
FILTER
rCIC2
RESAMPLER
SDFE[3:0]
SCLK[3:0]
SYNCA
SYNCB
SYNCC
SYNCD
RAM
COEFFICIENT
FILTER
MODE
rCIC2
RESAMPLER
DS(RD)
INB[13:0]
CS
RW (WR)
EXPB[2:0]
IENB
DTACK(RDY)
RAM
COEFFICIENT
FILTER
rCIC2
RESAMPLER
LIB-A
LIB-B
A[2:0]
D[7:0]
EXTERNAL SYNC
CIRCUITRY
JTAG
INTERFACE
BUILT-IN
SELF-TEST
REV. B
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