AD9631AR

Overview

The AD9631AR is a high-speed, wide-bandwidth voltage feedback operational amplifier manufactured by Analog Devices Inc. It features a small-signal bandwidth of 320 MHz and a large-signal bandwidth of 175 MHz at a gain of +1 V/V. The device operates on dual supplies ranging from ±3 V to ±5 V with a quiescent current of 17 mA. Key performance metrics include a slew rate of 1300 V/µs, settling time of 16 ns to 0.01% for a 2 V step, and ultralow distortion characterized by a third-order intercept of 46 dBm at 25 MHz. It is housed in an 8-lead SOIC package.

Feature Summary

• Voltage feedback architecture providing predictable operation and classical op amp structure.
• Ultralow harmonic distortion and low noise spectral density suitable for precision signal processing.
• High slew rate and fast settling time enabling accurate pulse response and transient handling.
• Unity gain stability allowing direct use in buffer configurations without external compensation.

Applications

• ADC input driver
• Differential amplifiers
• IF/RF amplifiers
• Pulse amplifiers
• Professional video

Procurement Notes

Verify the specific suffix 'AR' corresponds to the SOIC package variant when sourcing. Confirm that the operating temperature range meets the industrial specification of -40°C to +85°C. Ensure power supply bypassing components are selected according to the datasheet recommendations to maintain stability and minimize distortion at high frequencies.

Selection Notes

Select this component for applications requiring wide bandwidth and low distortion in a voltage feedback topology. It serves as a high-performance alternative to current feedback amplifiers where predictable gain behavior is critical. Consider the 320 MHz bandwidth and 1300 V/µs slew rate for driving high-speed data converters or processing wideband signals.

Part Context

The AD9631 is part of the AD9631/AD9632 family of ultralow distortion, wide bandwidth voltage feedback op amps. While the AD9631 is unity gain stable, its counterpart, the AD9632, is stable at gains of 2 or greater. Both devices share similar architectural benefits, combining the speed of current feedback designs with the stability of voltage feedback structures.

Replacement Considerations

The AD9621 and AD9622 are noted as predecessors with improved performance offered by the AD9631 series. Verify pin compatibility and electrical specifications against legacy designs before substitution.

FAQ

Is the AD9631 stable at unity gain?

Yes, the AD9631 is specifically designed to be unity gain stable.

What is the recommended feedback resistor value for optimal performance at G = +1?

For the AD9631 at a gain of +1, the optimum dynamic performance is achieved with a feedback resistor (RF) of 140 Ω.

How does the AD9631 differ from the AD9632 regarding stability?

The AD9631 is unity gain stable, whereas the AD9632 is stable only at gains of 2 or greater.