AD8328ARQ-REEL

Overview

The AD8328ARQ-REEL is a low-cost, single-supply cable line driver designed for upstream transmission in DOCSIS and EuroDOCSIS reverse path systems. It operates from a 5 V supply and features digitally programmable gain over a 59 dB range with 1 dB steps via an SPI interface. The device supports differential or single-ended inputs and maintains a 300 Ω differential output impedance to drive 75 Ω loads through a 2:1 transformer. Key performance metrics include a bandwidth of 107 MHz, -54 dBc SFDR at 65 MHz, and output noise of 1.2 nV/√Hz at minimum gain.

Feature Summary

• Digitally controlled gain adjustment over a 59 dB range using an 8-bit serial interface
• Low distortion performance suitable for QPSK and QAM modulation standards
• Integrated sleep mode reducing quiescent current to 20 μA
• Maintains 300 Ω output impedance during both transmit enable and disable states

Applications

• DOCSIS and EuroDOCSIS cable modems
• CATV set-top boxes
• Coaxial and twisted pair line drivers

Procurement Notes

Verify the specific package variant, as the AD8328 is available in 20-lead LFCSP and QSOP formats. Confirm that the ordering suffix corresponds to the required reel quantity and tape-and-reel specifications. Ensure compatibility with the target PCB footprint for the selected package type before procurement.

Selection Notes

Select this component for applications requiring precise digital gain control in upstream cable paths. Consider the 5 V supply requirement and the need for external AC coupling capacitors for input and bypass pins. Evaluate the thermal dissipation capabilities if operating near maximum gain codes, as quiescent current varies significantly with gain settings.

Part Context

The AD8328 belongs to Analog Devices' family of cable line drivers optimized for hybrid fiber-coaxial (HFC) networks. It serves as a power amplifier stage in upstream signal chains, replacing discrete solutions with an integrated, cost-effective alternative. The device is characterized for operation across automotive temperature ranges, ensuring reliability in diverse environmental conditions.

Replacement Considerations

Check for pin-compatible alternatives within the same product family that may offer updated packaging or revised electrical characteristics. Verify that any substitute maintains the 59 dB gain range and SPI interface compatibility to avoid redesigning the control logic.