Analog Devices Inc. AD637BRZ

The AD637BRZ, produced by Analog Devices Inc., is a high-accuracy, wideband RMS-to-DC converter. 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 AD637BRZ offers unprecedented performance in accuracy, bandwidth, and dynamic range, making it comparable to discrete and modular techniques.

• High Accuracy: 0.02% maximum nonlinearity for inputs from 0 V to 2 V rms, and 0.1% additional error for crest factors up to 3.
• Wide Bandwidth: Measures signals up to 8 MHz at 2 V rms input and up to 600 kHz at 100 mV rms input.
• Multiple Output Functions: Computes true RMS, mean square, absolute value, and provides a direct dB output with a 60 dB range.
• Chip Select/Power-Down Feature: Reduces supply current from 2.2 mA to 350 μA during periods of inactivity, facilitating use in remote or handheld applications.
• Input Protection: Input circuitry is protected from overload voltages exceeding supply levels, ensuring no damage if supply voltages are lost.
• On-Chip Buffer Amplifier: Can be used as an input buffer or in an active filter configuration to reduce AC ripple and increase accuracy.
• External Programming: Allows the user to select the 0 dB reference voltage to correspond to any level between 0.1 V and 2.0 V rms.

• Remote and Handheld Devices: The low power consumption in power-down mode makes it ideal for battery-powered devices.
• Audio and Signal Processing: Accurate measurement of complex waveforms is crucial in audio and signal processing applications.
• Industrial and Automotive Systems: Suitable for use in industrial and automotive environments due to its wide temperature range and robust design.
• Test and Measurement Equipment: Used in various test and measurement instruments where precise RMS measurements are required.

1. What is the maximum nonlinearity of the AD637BRZ for inputs from 0 V to 2 V rms?

   The maximum nonlinearity is 0.02%.

2. What is the bandwidth of the AD637BRZ at 2 V rms input?

   The bandwidth is up to 8 MHz.

3. How does the chip select/power-down feature benefit the AD637BRZ?

   This feature reduces the supply current from 2.2 mA to 350 μA during periods of inactivity, which is beneficial for remote or handheld applications.

4. What types of outputs can the AD637BRZ provide?

   The AD637BRZ can provide true RMS, mean square, absolute value, and direct dB output with a 60 dB range.

5. How is the input circuitry of the AD637BRZ protected?

   The input circuitry is protected from overload voltages exceeding supply levels, ensuring no damage if supply voltages are lost.

6. What is the purpose of the on-chip buffer amplifier in the AD637BRZ?

   The on-chip buffer amplifier can be used as an input buffer or in an active filter configuration to reduce AC ripple and increase accuracy.

7. Can the 0 dB reference voltage of the AD637BRZ be externally programmed?

   Yes, the user can select the 0 dB reference voltage to correspond to any level between 0.1 V and 2.0 V rms.

8. What are the available package types for the AD637BRZ?

   The AD637BRZ is available in a 16-lead SOIC_W package.

9. What is the operating temperature range for the commercial grade AD637BRZ?

   The operating temperature range is from 0°C to 70°C.

10. How does the AD637BRZ handle low frequency accuracy and ripple level?

    The low frequency accuracy, ripple level, and settling time are determined by an external capacitor that sets the averaging period.