AD8323ARU-REEL

Overview

The AD8323ARU-REEL is a digitally controlled variable gain amplifier optimized for coaxial line driving applications. It operates from a single 5 V supply with a gain range of 53.5 dB, adjustable in 0.7526 dB steps via an SPI interface. The device maintains a constant 75 Ω differential output impedance during power-up and power-down states. Key performance metrics include a –56 dBc third-order harmonic distortion at 21 MHz and a bandwidth of 100 MHz.

Feature Summary

• Maintains constant 75 Ω output impedance during power-up and power-down conditions
• Digitally programmable gain control via SPI interface with fine step resolution
• Low quiescent current operation with dedicated sleep mode functionality

Applications

• DOCSIS compliant upstream path transmission in cable modems
• HFC high-speed data modem line drivers
• Interactive set-top boxes requiring gain-programmable amplification
• General-purpose digitally controlled variable gain blocks

Procurement Notes

Verify the specific ordering suffix RU-28 corresponds to the 28-lead TSSOP package configuration. Confirm that the REEL designation aligns with the required manufacturing packaging format for automated assembly processes. Ensure compatibility with the specified thermal resistance characteristics on standard PCB layouts.

Selection Notes

Select this component for applications requiring precise digital gain adjustment in RF signal paths. The device supports both single-ended and differential input configurations. Designers must account for the internal DC bias level of approximately VCC/2 at both input and output pins when implementing AC coupling networks.

Part Context

This part belongs to the AD8323 family of variable gain amplifiers manufactured by Analog Devices. The ARU suffix indicates the commercial temperature range of –40°C to +85°C. The device is designed to replace discrete amplifier solutions in CATV infrastructure by integrating attenuation and buffering functions into a single low-cost IC.

Replacement Considerations

Public documentation confirms that the MA/COM ETC-1-IT-15 transformer can substitute the TOKO 617DB-A0070 transformer in typical application circuits without altering the amplifier's functional performance or impedance matching requirements.

FAQ

How does the AD8323 handle output impedance during power-down?

The device maintains a differential output impedance of 75 Ω even in power-down mode, eliminating the need for external termination resistors.

What is the gain resolution of the digital control interface?

The gain scales at 0.7526 dB per least significant bit (LSB) across an 8-bit serial word range.