AD8331ARQZ-R7

Overview

The AD8331ARQZ-R7 is a single-channel ultralow noise variable gain amplifier (VGA) from Analog Devices, housed in a 20-lead QSOP package. It operates on a single 5 V supply with a quiescent current of 25 mA per channel and power dissipation of 125 mW. The device features a 19 dB low-noise preamplifier and an X-AMP VGA providing a 48 dB gain range. Key electrical parameters include a 120 MHz bandwidth, 650 V/µs slew rate, and 0.74 nV/√Hz input voltage noise. Gain control is linear-in-dB at 50 dB/V over a 0 to 1 V input range.

Feature Summary

• Integrates an ultralow noise preamplifier with active input impedance matching capability via a single external resistor.
• Provides precise linear-in-dB gain scaling controlled by a 0 to 1 V analog voltage interface.
• Includes a selectable postamplifier with adjustable output clamping to prevent overload in downstream ADCs.

Applications

• Ultrasound and sonar time-gain controls
• High performance automatic gain control systems
• I/Q signal processing

Procurement Notes

Verify the specific ordering suffix against official documentation to confirm packaging format. The R7 suffix indicates reel packaging. Confirm pinout compatibility and thermal requirements for the 20-QSOP package during integration. Ensure supply voltage and gain control interfaces match system specifications before procurement.

Selection Notes

Select this component for applications requiring ultralow noise performance up to 120 MHz. The single-channel configuration suits space-constrained designs compared to dual or quad variants. Verify that the 5 V single-supply operation aligns with available power rails. Consider the programmable input resistance feature if source impedance matching is required without degrading noise figures.

Part Context

This part belongs to the AD8331/AD8332/AD8334 family of ultralow noise VGAs. While the AD8332 offers dual channels and the AD8334 provides four channels, the AD8331 is optimized as a single-channel solution. All variants share similar internal architectures including the X-AMP technology and low-noise preamplifiers.

Replacement Considerations

Public confirmed substitute part numbers are not provided in the source material.

FAQ

How is the LNA input impedance adjusted?

The LNA input impedance can be adjusted using a single external resistor connected to the RIZ pin, allowing matching to signal sources without compromising noise performance.

What is the gain control interface characteristic?

The gain control interface provides precise linear-in-dB scaling of approximately 50 dB/V for control voltages between 0 V and 1 V.