GENERAL DESCRIPTION

The AD6635 is a multimode, 8-channel, digital Receive Signal Processor (RSP) capable of processing up to four WCDMA channels. Each channel consists of four cascaded signal-processing elements: a frequency translator, two CIC decimating filters, and a programmable coefficient-decimating filter. Each input port has input level threshold detection circuitry for accommodating large dynamic ranges or situations where gain ranging converters are used. Quad 16-bit parallel output ports accommodate high data rate WBCDMA applications. On-chip interpolating half-band filters can also be used to further increase the output rate. In addition, each output port has a digital AGC for accommodating large dynamic ranges using smaller bit widths. The AGCs can maintain either signal level or clipping level, depending on their mode. Link port outputs are provided to enable glueless interfaces to Analog Devices’ TigerSHARC DSP core.

FEATURES

Four 80 MSPS Wideband Inputs (14 Linear Bits Plus 3 RSSI)

4 Real Input Ports/2 Complex Input Ports

Processes 4 Wideband Channels (UMTS or cdma2000

1x) or 8 GSM/EDGE, IS136 Channels

8 Independent Digital Receivers in a Single Package

Four 16-Bit Parallel Output Ports and Four 8-Bit Link Ports

4 Programmable Digital AGC Loops with 96 dB Range

Digital Resampling for Noninteger Decimation Rates

Programmable Decimating FIR Filters

4 Interpolating Half-Band Filters

Flexible Control for Multicarrier and Phased Array

Programmable Attenuator Control for Clip Prevention and

External Gain Ranging via Level Indicator

3.3 V I/O, 2.5 V CMOS Core

User Configurable Built-in Self Test (BIST) Capability

APPLICATIONS

Multicarrier, Multimode Digital Receivers

GSM, IS136, EDGE, PHS, IS95, UMTS, cdma2000

Micro and Pico Cell Systems, Software Radios

Wireless Local Loop

Smart Antenna Systems

In-Building Wireless Telephony