Overview
The AD637KRZ 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 AD637KRZ offers unprecedented performance in accuracy, bandwidth, and dynamic range, 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 statistical signals.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Nonlinearity (0 V to 2 V rms input) | 0.02% | |||
| Additional Error to Crest Factor of 3 | 0.1% | |||
| Bandwidth at 2 V rms input | 8 MHz | |||
| Bandwidth at 100 mV rms input | 600 kHz | |||
| dB Output Range | 60 dB | |||
| Quiescent Current | 2.2 mA | |||
| Quiescent Current in Power-Down Mode | 350 μA | |||
| Input Resistance | 20 kΩ | 25 kΩ | 30 kΩ | |
| Output Current | -0.13 mA | 5 mA | ||
| Temperature Range (Commercial Grade) | 0°C | 70°C |
Key Features
- High accuracy with 0.02% maximum nonlinearity for inputs from 0 V to 2 V rms.
- Wide bandwidth, supporting signals up to 8 MHz at 2 V rms input and up to 600 kHz at 100 mV rms input.
- Computes true RMS, mean square, or absolute value of complex waveforms.
- Direct dB output with a range of 60 dB available on a separate pin.
- Chip select/power-down feature to reduce quiescent current from 2.2 mA to 350 μA, facilitating low power consumption in remote or handheld applications.
- Input circuitry protected from overload voltages, ensuring no damage if supply voltages are lost.
- Laser wafer trimmed for rated performance without external trimming.
- On-chip buffer amplifier can be used as an input buffer or in an active filter configuration to reduce ac ripple and increase accuracy.
Applications
- Precision measurement in remote or handheld devices where low power consumption is critical.
- Wideband true RMS multiplexing by tying multiple AD637s together.
- Measurement of signals with high crest factors (up to 10) with less than 1% additional error.
- Industrial and commercial applications requiring high accuracy and wide bandwidth RMS measurements.
Q & A
- What is the primary function of the AD637KRZ?
The AD637KRZ is a high-accuracy, wideband RMS-to-DC converter that computes the true RMS value of any complex waveform and provides an equivalent DC output voltage.
- What is the maximum nonlinearity of the AD637KRZ for inputs from 0 V to 2 V rms?
The maximum nonlinearity is 0.02% for inputs from 0 V to 2 V rms.
- What is the bandwidth of the AD637KRZ at 2 V rms input?
The bandwidth at 2 V rms input is up to 8 MHz.
- How does the chip select/power-down feature work?
The chip select/power-down feature allows the user to reduce the quiescent current from 2.2 mA to 350 μA during periods when the RMS function is not in use, and the output goes to a high impedance state when powered down.
- What is the temperature range for the commercial grade AD637KRZ?
The commercial grade AD637KRZ operates within a temperature range of 0°C to 70°C.
- Can the AD637KRZ handle signals with high crest factors?
Yes, the AD637KRZ can measure signals with crest factors up to 10 with less than 1% additional error.
- What types of packages are available for the AD637KRZ?
The AD637KRZ is available in 14-lead SBDIP, 14-lead CERDIP, and 16-lead SOIC_W packages.
- How is the dB output feature of the AD637KRZ utilized?
The AD637KRZ provides a direct dB output with a range of 60 dB available on a separate pin, allowing for easy measurement in dB scale.
- What is the purpose of the on-chip buffer amplifier?
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 measurement accuracy.
- Is external trimming required for the AD637KRZ?
No, the AD637KRZ is laser wafer trimmed to achieve rated performance without external trimming.
