GENERAL DESCRIPTION
The AD6633 is a multichannel, wide bandwidth digital upconverter (DUC) with crest factor reduction (CFR) technology, which is available in 4-channel or 6-channel versions. It processes 20-bit baseband input data and generates 18-bit, wideband, real, or complex output data at up to 125 MSPS. This rate is suitable for driving digital-to-analog converters (DACs) at the first intermediate frequency (IF) directly.

FEATURES
   4 or 6 wideband digital upconverter channels
   VersaCREST crest reduction engine reduces demands on
      external power amplifiers
   One 20-bit complex input port (I, Q interleaved), shared
      among 4 or 6 processing channels
   Two 18-bit output ports for parallel I and Q or a single 18-bit
      output port for interleaved I and Q
   All-pass phase equalizer filters (meets IS-95 requirements)
   Programmable RAM coefficient FIR filters (RCF) with
      resampling
   FIR interpolating filters, 2 per channel
   Fifth-order interpolating CIC filter, 1 per channel
   Full complex NCO, 32-bit tuning resolution (fine), worst spur
      better than −105 dBc, 1 per channel
   Complex FIR filter for frequency equalization or additional
      filtering
   Output automatic gain control
   Full complex composite NCO, 6-bit tuning resolution
   16-bit/8-bit MicroPort (Intel® or Motorola® mode)
   Serial control port (SPI®- or SPORT-compatible)
   3.3 V I/O and 1.8 V core supplies
   JTAG boundary scan
   User-configurable, built-in, self-test (BIST) capability

APPLICATIONS
   Cellular/PCS basestations
   Micro/pico cell basestations
   Multicarrier cdma2000®, WCDMA, TD-SCDMA basestations
   Broadband wireless access head ends (LMDS, MMDS)
   Software defined radios
   High speed signal processing applications