Overview
The AD637JRZ-R7, produced by Analog Devices Inc., is a high-accuracy, wideband RMS-to-DC converter. This integrated circuit computes the true root mean square (RMS), mean square, or absolute value of any complex AC (or AC plus DC) input waveform and provides an equivalent DC output voltage. The AD637 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 the signal.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Maximum Nonlinearity | 0.02% | - |
| Additional Error to Crest Factor of 3 | 0.10% | - |
| Bandwidth at 2 V rms Input | 8 MHz | - |
| Bandwidth at 100 mV rms Input | 600 kHz | - |
| dB Output Range | 60 dB | - |
| Supply Current (Active) | 2.2 mA | - |
| Supply Current (Power-Down) | 350 μA | - |
| Package Types | 14-lead SBDIP, 14-lead CERDIP, 16-lead SOIC_W | - |
| Operating Temperature Range | 0°C to 70°C (Grade J, K), -40°C to +85°C (Grade A, B), -55°C to +125°C (Grade S) | - |
Key Features
- High accuracy with 0.02% maximum nonlinearity for 0 V to 2 V rms input and 0.10% additional error to crest factor of 3.
- Computes true RMS, square, mean square, and absolute value of complex waveforms.
- Wide bandwidth: up to 8 MHz at 2 V rms input and up to 600 kHz at 100 mV rms input.
- dB output with a range of 60 dB available on a separate pin.
- Chip select/power-down feature for reducing quiescent current from 2.2 mA to 350 μA and high impedance output state when powered down.
- Input circuitry protected from overload voltages in excess of supply levels.
- Laser wafer trimmed for rated performance without external trimming.
- On-chip buffer amplifier for input buffering or active filter configuration.
Applications
The AD637JRZ-R7 is suitable for various applications requiring precise RMS measurements, including:
- Remote or handheld devices where low power consumption is critical.
- Industrial and commercial measurement systems.
- Military and aerospace applications due to its wide temperature range and high reliability.
- Audio and signal processing systems where accurate RMS values are necessary.
- Power monitoring and control systems.
Q & A
- What is the primary function of the AD637JRZ-R7?
The AD637JRZ-R7 computes the true RMS, square, mean square, or absolute value of any complex AC (or AC plus DC) input waveform and provides an equivalent DC output voltage.
- What is the maximum nonlinearity of the AD637JRZ-R7?
The maximum nonlinearity is 0.02% for 0 V to 2 V rms input.
- What is the bandwidth of the AD637JRZ-R7 at 2 V rms input?
The bandwidth is up to 8 MHz at 2 V rms input.
- How does the chip select/power-down feature work?
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, and the output goes to a high impedance state when powered down.
- What types of packages are available for the AD637JRZ-R7?
The AD637JRZ-R7 is available in 14-lead SBDIP, 14-lead CERDIP, and 16-lead SOIC_W packages.
- What is the operating temperature range for the AD637JRZ-R7?
The operating temperature range varies by grade: 0°C to 70°C (Grade J, K), -40°C to +85°C (Grade A, B), and -55°C to +125°C (Grade S).
- Is the AD637JRZ-R7 protected against overload voltages?
Yes, the input circuitry is protected from overload voltages in excess of the supply levels.
- What external components are required for the AD637JRZ-R7?
The only external component required is a capacitor that sets the averaging period.
- Can the AD637JRZ-R7 be used in multiplexing applications?
Yes, when powered down, the output goes to a high impedance state, allowing several AD637s to be tied together to form a wideband true RMS multiplexer.
- How does the on-chip buffer amplifier function?
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.
