AD8326ARE

Overview

The AD8326ARE is a high-output power, digitally controlled variable gain amplifier optimized for coaxial line driving applications. It supports the MCNS-DOCSIS upstream standard with an 8-bit serial gain control providing a 53.5 dB range in 0.75 dB steps. The device maintains a differential 75 Ω output impedance and operates on dual ±5 V or single 10 V supplies. Key electrical parameters include a 100 MHz upper bandwidth, –45 dBmV output noise level (160 kHz), and a 1 dB compression point of 25 dBm at 10 MHz.

Feature Summary

• Digitally programmable gain via 8-bit serial interface with 0.75 dB step resolution
• Maintains 75 Ω differential output impedance across all gain settings and power states
• Integrated sleep mode reduces quiescent current to approximately 4 mA
• Optimized low distortion performance for DOCSIS reverse path transmission

Applications

• Gain-programmable line drivers for cable modems
• CATV telephony modem upstream amplifiers
• CATV terminal devices requiring precise output power control
• General-purpose digitally controlled variable gain blocks

Procurement Notes

Verify component authenticity as the AD8326 series is listed as obsolete by Analog Devices. Confirm that the specific ARE suffix corresponds to the TSSOP-28 package variant designed for dual ±5 V or single 10 V supply operation. Ensure compatibility with existing thermal management strategies, as the exposed pad requires direct soldering to a ground plane for adequate heat dissipation during high-power operation.

Selection Notes

Select the AD8326ARE when system architecture utilizes dual ±5 V or single 10 V power rails rather than the 12 V required by the ARP variant. This model is suitable for applications requiring up to 65 dBmV output power with lower cost and smaller package footprint. Verify that the 53.5 dB gain range and 0.75 dB step precision meet the dynamic range requirements of the specific cable modem or CATV application design.

Part Context

The AD8326 family consists of two primary models: the AD8326ARP housed in a Power SOIC package for 12 V systems, and the AD8326ARE in a TSSOP package for lower voltage applications. Both variants share identical functional block diagrams and digital control interfaces but differ in thermal characteristics and maximum supported output power levels based on their respective supply voltage optimizations.

Replacement Considerations

As the AD8326 is obsolete, no direct public substitutes are confirmed within the same product line. Designers must evaluate alternative high-output power programmable CATV line drivers from other manufacturers. Any replacement must be verified to support DOCSIS upstream standards, maintain 75 Ω output impedance, and accommodate the specific supply voltage constraints of the original ±5 V or 10 V design.

FAQ

How does the AD8326ARE handle output impedance during power-down?

The device maintains its 75 Ω differential output impedance in both power-up and power-down conditions, eliminating the need for external back termination resistors.

What is the function of the SLEEP pin?

Driving the SLEEP pin low activates a low-power sleep mode that reduces the quiescent supply current to approximately 4 mA while maintaining signal isolation.

Can the AD8326ARE accept single-ended inputs?

Yes, the device accepts single-ended inputs, though it is optimized for differential drive. Single-ended operation requires specific input termination configurations to balance the VIN+ and VIN– pins.