AD8328ARQ

Overview

The AD8328ARQ is a 5 V upstream cable line driver designed for DOCSIS and EuroDOCSIS reverse path transmission systems. It 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, typically matched to 75 Ω loads using a 2:1 transformer. Key performance metrics include a bandwidth of 107 MHz, an output noise level of 1.2 nV/√Hz at minimum gain, and distortion specifications of −57.5 dBc SFDR at 21 MHz and −54 dBc at 65 MHz.

Feature Summary

• Digitally controlled gain adjustment via SPI interface with 1 dB resolution
• Maintains constant 300 Ω differential output impedance in transmit enable and disable states
• Integrated sleep mode reducing quiescent current to 20 μA
• Supports both differential and single-ended input signal configurations

Applications

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

Procurement Notes

Verify the specific package variant (LFCSP or QSOP) as the base part number may correspond to multiple physical footprints. Confirm that the component meets the required operating temperature range of −40°C to +85°C for your application environment. Ensure compatibility with 5 V supply rails and check for any obsolete status indicators from Analog Devices before finalizing procurement plans.

Selection Notes

Select this component for applications requiring precise digital gain control in upstream cable transmission paths. The device is suitable for designs needing low distortion at high output levels up to 60 dBmV. Consider the available power-down modes if system energy efficiency is critical. Ensure the design accommodates the necessary external components, such as the 2:1 output transformer and AC coupling capacitors, for proper impedance matching and biasing.

Part Context

The AD8328 is a specialized analog front-end component manufactured by Analog Devices Inc. It belongs to the family of cable line drivers intended for broadband communication infrastructure. The ARQ suffix indicates a specific thermal and packaging configuration within the product line, distinct from other variants like the standard AR or AQ packages.

Replacement Considerations

No public confirmed substitutes are identified in the provided documentation. As the AD8328 is marked obsolete, alternative solutions must be sourced through official Analog Devices channels or verified third-party distributors ensuring functional equivalence in gain range, impedance, and DOCSIS compliance.