AD8328ACPZ

Overview

The AD8328ACPZ is a 5 V upstream cable line driver designed for DOCSIS and EuroDOCSIS reverse path transmission. It features digitally programmable gain in 1 dB steps over a 59 dB range, controlled via an SPI interface. The device supports differential or single-ended inputs with impedances of 1.6 kΩ and 800 Ω respectively. It maintains a 300 Ω differential output impedance, suitable for driving 75 Ω loads through a 2:1 transformer. Key performance metrics include -57.5 dBc SFDR at 21 MHz and -54 dBc at 65 MHz, with an upper bandwidth of 107 MHz.

Feature Summary

• Digital gain control via SPI interface with 1 dB step resolution
• Maintains consistent 300 Ω output impedance in transmit enable and disable states
• Integrated sleep mode reducing supply current to 20 μA
• Optimized for low distortion and noise in upstream cable applications

Applications

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

Procurement Notes

Verify the component status as obsolete before procurement planning. Confirm that the LFCSP-20 package variant matches the required thermal and mechanical specifications for the target application. Ensure compatibility with existing serial interface logic levels and timing requirements during integration.

Selection Notes

Select this component for applications requiring precise digital gain adjustment in upstream cable paths. Consider the 5 V supply requirement and the need for external transformers for output matching. Evaluate the trade-off between power consumption in active versus sleep modes based on system duty cycles.

Part Context

The AD8328 belongs to Analog Devices' lineup of specialized amplifiers for cable modem infrastructure. It serves as a cost-effective solution for meeting DOCSIS standards by providing high linearity and flexible gain control. The device integrates essential functions for upstream signal conditioning, simplifying the design of cable modems and related communication equipment.

Replacement Considerations

No public confirmed substitutes are available. As the part is marked obsolete, alternative solutions must be evaluated based on functional equivalence, including gain range, distortion performance, and interface compatibility.