AD8018AR

Overview

The AD8018AR is a dual high-speed current feedback amplifier designed for single-supply xDSL applications. It operates on a 3.3 V to 8 V supply with a typical quiescent current of 9 mA per amplifier. The device features rail-to-rail output, delivering 400 mA into a 10 Ω differential load while maintaining low distortion. Key electrical parameters include a 130 MHz bandwidth, 300 V/µs slew rate, and 4.5 nV/√Hz input voltage noise density at 100 kHz.

Feature Summary

• Rail-to-rail output capability allows driving signals within 0.5 V of the power supply rails.
• High output current drive of 400 mA supports low-distortion signaling into differential loads.
• Integrated logic control enables full power, standby, and shutdown modes for power optimization.

Applications

• xDSL USB, PCI, or PCMCIA-based Customer Premise Equipment (CPE)
• Consumer DSL modems requiring single-supply operation
• Twisted pair line drivers for ADSL, SDSL, and VDSL systems

Procurement Notes

Verify package availability as the SOIC-8 variant may be discontinued in certain regions. Confirm that the specific ordering suffix matches the required package type, such as TSSOP-14 for models with power-down pins. Ensure the selected component meets the intended temperature range specifications for the target application environment.

Selection Notes

Select the AD8018ARU variant when digital standby and shutdown control via PWDN1 and PWDN0 pins is required. Choose the AD8018AR model for applications where these logic inputs are unnecessary and a smaller footprint is preferred. Consider thermal dissipation limits when operating near maximum supply voltages or delivering high line power.

Part Context

The AD8018 series comprises dual high-speed amplifiers fabricated using Analog Devices' XFCB process. This technology provides high bandwidth and fast slew rates while minimizing power consumption. The family includes variants in 8-lead SOIC and 14-lead TSSOP packages, catering to different integration needs in cost-sensitive communication interfaces.

Replacement Considerations

Public documentation indicates that the AD8018ARZ model has been discontinued. Designers should evaluate the AD8018ARU or other active AD8018 variants as potential replacements, ensuring pin compatibility and functional equivalence for the specific circuit requirements.

FAQ

How does the AD8018 achieve rail-to-rail output performance?

The device utilizes a novel two-stage current feedback architecture with a patent-pending complementary common-emitter output stage, allowing it to swing to within 0.5 V of either power supply rail.

What is the function of the PWDN1 and PWDN0 pins?

These logic inputs allow selection between three operational modes: full power, standby (low impedance outputs), and shutdown (high impedance outputs) to manage power consumption.

Why is resistor selection critical for this amplifier?

As a current feedback amplifier, its bandwidth and stability depend primarily on the feedback resistor value. Incorrect selection can lead to instability or degraded multi-tone performance.