AD9879BSZ

Overview

The AD9879BSZ is a single-supply mixed-signal front end (MxFE) designed for set-top box and cable modem applications. It integrates a transmit path with a 12-bit direct IF DAC operating up to 232 MSPS, a 16× upsampling interpolation filter, and a DDS supporting carrier frequencies up to 65 MHz. The receive path includes a 12-bit ADC, a 10-bit ADC, and dual 7-bit I/Q ADCs, all sampling up to 33 MSPS. A programmable Σ-Δ DAC and a dedicated cable amplifier interface are also included. The device operates on a 3.3 V supply within the commercial temperature range of −40°C to +85°C.

Feature Summary

• Transmit Path: 12-bit TxDAC+ running at 232 MSPS with integrated 16× interpolation filter and DDS for carriers up to 65 MHz.
• Receive Path: Includes a 12-bit ADC, a 10-bit ADC, and dual 7-bit I/Q ADCs with maximum conversion rates up to 33 MSPS.
• Video Processing: Optional video clamping input allows simultaneous processing of NTSC and QAM channels via the 10-bit ADC.
• Control Interfaces: Features a programmable Σ-Δ DAC and a CA port for controlling external cable driver amplifiers.

Applications

• DOCSIS, EURO-DOCSIS, DVB, and DAVIC-compliant set-top boxes
• Cable modems and satellite systems
• Power line modems
• QAM, OFDM, and FSK modulation systems

Procurement Notes

Verify that the ordering suffix 'B' corresponds to the commercial temperature grade (-40°C to +85°C). Confirm package compatibility with the 100-lead MQFP footprint. Ensure power supply decoupling meets the specified requirements for the 3.3 V analog and digital rails to maintain signal integrity.

Selection Notes

Select this component when a cost-effective MxFE solution is required for hybrid fiber-coaxial networks. The AD9879 offers enhanced undersampling performance compared to the pin-compatible AD9873. Ensure system clock inputs align with the internal PLL capabilities for the desired data throughput.

Part Context

The AD9879 serves as a lower-cost alternative to the AD9873 while maintaining pin compatibility. It is part of Analog Devices' MxFE family, targeting broadband access infrastructure. The BSZ variant denotes the specific temperature rating and RoHS-compliant packaging configuration.

Replacement Considerations

The AD9873 is a pin-compatible predecessor. Verify if the specific performance enhancements or cost differences between the two models impact the design requirements before substitution.