DOCSIS 3.1 High-Density SCQAM and OFDM Downstream Cable Modulator

The MAX5861 is an integrated, high-density, SCQAM and OFDM downstream cable modulator, digital up-converter (DUC) and RF digital-to-analog converter (RF-DAC). The MAX5861 is DOCSIS 3.1-compliant and is optimized for converged cable access platform (CCAP) hardware. The MAX5861 performs baseband I/Q symbols to RF up-conversion to digitally synthesize a selectable combination of SCQAM and OFDM blocks on a single RF port. A combination of up to six 192MHz blocks of SCQAM or OFDM channels can be powered on at any one time, where a block is defined as either 32 X 6MHz (or 24 X 8MHz) SCQAM channels or an OFDM channel (up to 192MHz wide). The MAX5861 features three differential time-multiplexed input data ports that support LVDS or SSTL 1.2/1.5 in DDR mode.

The MAX5861 SCQAM input port A accepts 10-bit Forward Error Correction (FEC)-encoded data for up to 160 (6MHz) individually programmable channels. The SCQAM path performs QAM mapping, root raised cosine (RRC) pulse shaping, and resampling, compliant with ITU-T J.83 Annex A, B, and C. This port also supports 1024-QAM with the use of an offset bias bit. Up to four channels can be operated in RRC filter bypass mode at up to 2.5Msym/s for legacy communications to older generation devices.

Each of two available 9-bit OFDM ports, B or C, support up to three 12-bit OFDM IFFT-processing channels. Each IFFT-processing channel supports OFDM blocks of up to 192MHz bandwidth with selectable 4k or 8k subcarriers and up to 4096-QAM modulation options. Each of the two OFDM ports also allow bypassing of the IFFT processing with a single 18-bit I/Q data path to support user-defined modulation at up to 192MHz bandwidth.

A cascade of interpolation filters, complex modulators, channel combiners and Direct Digital Frequency Synthesizers (DDFS) up-convert the SCQAM and/or OFDM signals with full frequency agility from 43MHz to 1218MHz. The up-converted spectrum is fed to a Digital Pre-Distortion (DPD) block to compensate for distortion performance limitations in the DAC and external output amplifiers.

Applications

* CCAP, Edge QAM, CMTS * DOCSIS 3.0/3.1 and DVB-C/C2 * Multi-Dweller Units (MDU), Mini-Headends * Remote PHY, Coax Media Converters

* High-Density Cable Downstream Modulator

* Combine Up to Six 192MHz Blocks of 32 x 6MHz SCQAM Channels and DOCSIS 3.1 OFDM Channels

* Integrated 14-Bit 4.9152Gsps RF-DAC

* Highly Flexible and Configurable

* ITU-T J.83 Annex A, B, and C SCQAM Channels

* IFFT Processing D3.1 OFDM Channels

* LVDS or SSTL 1.2/1.5 DDR Data Ports

* One 10-Bit SCQAM Port with 160-Channel Capacity

* Two 9-Bit OFDM Ports with 6 OFDM-Channel Capacity

* Channel Bandwidths:

* 1MHz to 8MHz SCQAM

* 24MHz/48MHz/96MHz/192MHz OFDM

* 192MHz IFFT Bypass Mode

* Full SCQAM Agility within 192MHz Block

* Block Agility within 1218MHz Output Bandwidth

* Additional Features Ease RF Design

* Programmable Digital Predistortion

* High Output Power: 9dBm (Peak CW)

* Low-Power, Compact Solution

* 5.9W with 128 SCQAMs + 2 OFDM Channels

* Operating Temperature Range TA = -40°C to TJ = +110°C

* 12mm x 18mm, 308-Ball LFBGA