Overview
The AD637JD is a high-accuracy, wideband rms-to-dc converter produced by Analog Devices Inc. This integrated circuit is designed to compute the true root mean square (rms), mean square, or absolute value of any complex ac (or ac plus dc) input waveform and provide an equivalent dc output voltage. The AD637JD offers unprecedented performance in accuracy, bandwidth, and dynamic range, making it comparable to discrete and modular techniques. It is particularly useful because the true rms value of a waveform relates directly to the power of the signal and the standard deviation of the signal.
Key Specifications
| Parameter | Value | Comments |
|---|---|---|
| Maximum Nonlinearity | 0.02% (0 V to 2 V rms input) | |
| Additional Error to Crest Factor of 3 | 0.10% | |
| Bandwidth | Up to 8 MHz at 2 V rms input, 600 kHz at 100 mV rms | |
| dB Output Range | 60 dB | Direct dB value of the rms output |
| Supply Current | 2.2 mA (active), 350 μA (power-down) | |
| Temperature Range | 0°C to 70°C (Grade J and K), -40°C to +85°C (Grade A and B), -55°C to +125°C (Grade S) | |
| Package Types | 14-lead SBDIP, 14-lead CERDIP, 16-lead SOIC_W |
Key Features
- High Accuracy: 0.02% maximum nonlinearity for inputs from 0 V to 2 V rms.
- Wide Bandwidth: Up to 8 MHz at 2 V rms input and 600 kHz at 100 mV rms.
- dB Output: Direct dB value of the rms output with a range of 60 dB.
- Chip Select/Power-Down Feature: Reduces supply current from 2.2 mA to 350 μA during periods of inactivity.
- Input Protection: Protected from overload voltages in excess of the supply levels.
- On-Chip Buffer Amplifier: Can be used as an input buffer or in an active filter configuration to reduce ac ripple.
- Customizable Settings: Externally programmed reference current allows selection of the 0 dB reference voltage between 0.1 V and 2.0 V rms.
Applications
- Signal Processing: Ideal for applications requiring precise signal processing, such as in audio, medical, and industrial equipment.
- Process Control and Automation: Used in control systems where accurate measurement of signal power is crucial.
- Scientific Experiments: Suitable for high-precision signal processing in scientific research and analysis.
- Remote Sensing: Applicable in remote sensing applications where real-time signal processing is necessary.
- Automotive Applications: Can be used in automotive systems where reliable and precise signal processing is required).
Q & A
- Q: What is the maximum nonlinearity of the AD637JD?
A: The AD637JD has a maximum nonlinearity of 0.02% for inputs from 0 V to 2 V rms).
- Q: What is the bandwidth of the AD637JD?
A: The AD637JD has a bandwidth of up to 8 MHz at 2 V rms input and 600 kHz at 100 mV rms).
- Q: Does the AD637JD require external calibration or adjustment?
A: No, the AD637JD is designed for plug-and-play operation and does not require any calibration or adjustment).
- Q: How does the chip select/power-down feature work?
A: The chip select connection allows the user to decrease the supply current from 2.2 mA to 350 μA during periods when the rms function is not in use).
- Q: What types of packages are available for the AD637JD?
A: The AD637JD is available in 14-lead SBDIP, 14-lead CERDIP, and 16-lead SOIC_W packages).
- Q: Is the AD637JD protected against overload voltages?
A: Yes, the input circuitry of the AD637JD is protected from overload voltages in excess of the supply levels).
- Q: Can the AD637JD be used in high-frequency applications?
A: While the AD637JD has a wide bandwidth, it is generally suited for low-to-medium frequency applications. For very high-frequency requirements, alternative devices may be more appropriate).
- Q: What is the purpose of the on-chip buffer amplifier?
A: The on-chip buffer amplifier can be used either as an input buffer or in an active filter configuration to reduce ac ripple and increase accuracy).
- Q: Can the AD637JD be used in automotive applications?
A: Yes, the AD637JD can be used in automotive applications where precise signal processing and reliable operation are crucial).
- Q: How does the AD637JD handle temperature variations?
A: The AD637JD is available in different temperature grades: Grade J and K for commercial (0°C to 70°C), Grade A and B for industrial (-40°C to +85°C), and Grade S for military (-55°C to +125°C)).
