This document describes the features and characteristics of Analog Devices' Multichannel Digital Upconverter with VersaCREST™ Crest Reduction Engine AD6633 Rev. Sp0. The product features 4 or 6 wideband digital upconverter channels, and the VersaCREST crest reduction engine reduces demands on external power amplifiers. It also has a 20-bit complex input port (I, Q interleaved), shared among 4 or 6 processing channels. There are two 18-bit output ports for parallel I and Q or a single 18-bit output port for interleaved I and Q. It meets IS-95 requirements with all-pass phase equalizer filters. The product includes programmable RAM coefficient FIR filters (RCF) with resampling FIR interpolating filters, 2 per channel. It also has a fifth-order interpolating CIC filter, 1 per channel. The full complex NCO has 32-bit tuning resolution (fine) with a worst spur better than -105 dBc, 1 per channel. It includes a complex FIR filter for frequency equalization or additional filtering, output automatic gain control, and full complex composite N.
The AD6633 is a multichannel, wide‑bandwidth digital upconverter (DUC) available in 4‑ or 6‑channel versions. It processes 20‑bit complex baseband input data and produces 18‑bit real or complex output at up to 125 MSPS, suitable for driving DACs directly at the first IF.
The device includes a VersaCREST crest‑reduction engine, programmable RAM‑coefficient FIR filters, a fifth‑order CIC interpolator, and per‑channel 32‑bit NCOs. Power consumption is low (≈75 mW per channel) and the part operates from 3.3 V I/O and 1.8 V core supplies, with 5 V‑tolerant I/O pins and SPI/SPORT‑compatible serial control.
| Number of channels | 4 or 6 |
|---|---|
| Input port width | 20‑bit complex |
| Output ports | Two 18‑bit ports (parallel) or one 18‑bit interleaved port |
| NCO tuning resolution | 32‑bit (fine) |
| Power consumption per channel | 75 mW |
| Total power consumption | 1.4 W |
| I/O tolerance | 5 V tolerant |
| Serial control interface | SPI/SPORT‑compatible |
The AD6633 is available in versions with either 4 or 6 wideband digital upconverter channels.
Typical power consumption is about 75 mW per channel.
The AD6633 has a single 20‑bit complex input port (I, Q interleaved).