AD8327ARUZ

Overview

The AD8327ARUZ is a digitally controlled variable gain amplifier optimized for coaxial line driving in DOCSIS upstream applications. It provides a programmable gain range of 48.16 dB with 6.02 dB steps via an 8-bit serial interface. The device maintains a constant 75 Ω output impedance during transmit enable and disable modes. Key electrical specifications include a maximum gain of 30 dB, minimum gain of -19.16 dB, and a -3 dB bandwidth of 160 MHz. It operates from a single 5 V supply with quiescent currents ranging from 5 mA in sleep mode to 135 mA at maximum gain.

Feature Summary

• Maintains constant 75 Ω output impedance across all gain settings and transmit states
• Supports SPI-compatible digital control for precise gain adjustment
• Includes dedicated transmit enable/disable and low-power sleep modes
• Optimized for low distortion and noise performance in cable modem upstream paths

Applications

• DOCSIS high-speed data modems
• Interactive cable set-top boxes
• PC plug-in cable modems
• Gain-programmable line drivers
• General-purpose digitally controlled variable gain blocks

Procurement Notes

Verify the specific ordering suffix RU-20 corresponds to the 20-lead TSSOP package configuration required for your PCB layout. Confirm that the temperature range specification meets your operational environment requirements. Ensure that the obsolete status noted in the documentation does not conflict with long-term availability needs for your production cycle.

Selection Notes

Select this component when a fixed 75 Ω output impedance is critical for direct coaxial cable interfacing without external matching networks. Choose this part for applications requiring coarse step attenuation control via a simple serial interface. Consider the power consumption profiles in transmit enable versus sleep modes when designing battery-powered or thermally constrained systems.

Part Context

This device belongs to Analog Devices' family of digitally controlled amplifiers designed for cable television infrastructure. It serves as a key upstream power amplifier solution for meeting MCNS-DOCSIS standards. The architecture integrates a low-noise buffer, a digitally controlled attenuator, and a high-power output stage into a single monolithic IC.

Replacement Considerations

No public confirmed substitutes are listed in the provided documentation. As the datasheet indicates the part is obsolete, alternative sourcing strategies or redesign efforts may be necessary to maintain supply continuity for existing products.