AD8325ARUZ-REEL

Overview

The AD8325ARUZ-REEL is a digitally controlled variable gain amplifier optimized for coaxial line driving in DOCSIS upstream applications. It operates from a single 5 V supply with a gain range of 59.45 dB, adjustable in 0.7526 dB steps via an 8-bit serial interface. The device maintains a constant 75 Ω differential output impedance and supports transmit enable/disable modes. Key electrical parameters include a bandwidth of 100 MHz, quiescent current of 133 mA in transmit mode, and operation within a temperature range of -40°C to +85°C.

Feature Summary

• Digitally programmable gain control with fine step resolution
• Constant 75 Ω output impedance maintained across all gain settings and transmit states
• Integrated sleep mode for significant power reduction
• SPI-compatible serial interface for gain adjustment

Applications

• DOCSIS high-speed data modems
• Interactive cable set-top boxes
• PC plug-in cable modems
• Gain-programmable line drivers

Procurement Notes

Verify the specific package variant (RU vs RUZ) against design requirements, as suffixes may indicate lead-free composition or reel packaging type. Confirm that the digital control logic levels are compatible with the host microcontroller or FPGA interface. Ensure proper decoupling capacitors are placed near all VCC pins to maintain signal integrity during high-current switching events.

Selection Notes

Select this component for applications requiring precise, digitally controlled attenuation in CATV upstream paths. It is suitable where maintaining a fixed 75 Ω impedance is critical regardless of gain setting. Consider the 133 mA supply current for power budgeting and ensure the PCB layout supports the thermal dissipation capabilities of the TSSOP-28 package.

Part Context

This part belongs to the AD8325 family of variable gain amplifiers manufactured by Analog Devices. It is specifically designed for cable modem and CATV line driver applications. The ARUZ-REEL designation indicates a Pb-free version packaged in a 28-lead TSSOP on a tape and reel for automated assembly.

Replacement Considerations

Public documentation notes that the TOKO 617DB-A0070 transformer can be substituted with the MACOM ETC-1-IT-15 in application circuits. No direct functional pin-to-pin replacements for the amplifier itself are explicitly confirmed in the provided source material.