AD640JN

Instrumentation, Op Amps, Buffer Amps Overview

The AD640JN is a monolithic demodulating logarithmic amplifier manufactured by Analog Devices. It operates on dual power supplies ranging from ±4.5 V to ±7.5 V, with a typical supply voltage of ±5 V. The device provides a dynamic range of 50 dB and supports a signal bandwidth up to 120 MHz. It features five cascaded DC-coupled amplifier/limiter stages, each offering 10 dB of small-signal voltage gain and a -3 dB bandwidth of 350 MHz. The component utilizes continuous detection to produce an output current proportional to the logarithm of the input voltage. It is housed in a 20-pin PDIP package designed for through-hole mounting.

Instrumentation, Op Amps, Buffer Amps Feature Summary

• Features five cascaded DC-coupled amplifier/limiter stages with integrated full-wave detectors for continuous logarithmic detection
• Provides a video output current proportional to the logarithm of the absolute value of the input voltage
• Includes internal resistors to convert output current to voltage with selectable conversion slopes
• Laser-calibrated to ensure high accuracy across the specified operating temperature range

Instrumentation, Op Amps, Buffer Amps Applications

• Radar systems
• Sonar systems
• Ultrasonic testing equipment
• RF power measurement instruments

Instrumentation, Op Amps, Buffer Amps Procurement Notes

Verify the specific suffix 'JN' confirms the commercial grade temperature rating and PDIP-20 package configuration. Confirm that external low-pass filtering is included in the design, as the AD640JN lacks an integrated filter. Ensure power supply decoupling meets the requirements for the ±4.5 V to ±7.5 V operating range to maintain stability.

Instrumentation, Op Amps, Buffer Amps Selection Notes

Select this component when a single-chip solution for wide dynamic range logarithmic detection is required without the need for an internal low-pass filter. It is suitable for applications where the user needs to define the cutoff frequency independently to achieve fast rise times. Consider the 50 dB dynamic range limit per chip; cascade multiple units if wider ranges are necessary.

Instrumentation, Op Amps, Buffer Amps Part Context

The AD640 belongs to a family of complete monolithic logarithmic amplifiers produced by Analog Devices. It is distinct from other models in the series by its specific packaging and temperature rating options. The device is part of the company's portfolio for precision analog signal processing, targeting high-frequency measurement and control applications.

Instrumentation, Op Amps, Buffer Amps Replacement Considerations

The AD640T serves as the military-grade equivalent with extended temperature capabilities. The AD640B is the industrial-grade alternative. Verify pin compatibility and thermal specifications before substituting.