Module parameters:
Module model: AD637
Module type: RF logarithmic detector
Module supply voltage: ±5V ±5V--±15V (maximum ±18V)
Module supply current: 5mA; 5mA--15mA
Input signal form: single-ended
Input voltage range: -45dBm - +30dBm; within 7VRMS
Input frequency range: DC-8MHz; please refer to the test table for different frequency bands
Input impedance: 50 ohms
Output voltage range: 0.85V-2.6V; based on actual measured values, there are differences between different modules
Input signal characteristics: input coupling; avoid the introduction of DC components and make the module output value inaccurate; protect the module from DC impact damage; but adding a large capacitor in the low frequency band will make the charging time constant too large
Output current: 2mA (max); the output is a voltage signal, generally without current.
Module dynamic range: 60dB
Module protection: reverse connection protection, unlimited current protection
Module shield: no shield cover
Module heating factors: excessive power supply voltage damages the chip or the module is damaged
Module working temperature: 0℃--+70℃; industrial grade
Module features: LED indication of module power supply, anti-reverse connection of diodes, low-pass filter with about 100Hz after output
Applications: Peak voltage detection, data acquisition
Module interface type: SMA signal input, XH2.54 foolproof socket input and output, 5.08-3PIN power socket
Module description:
AD637 is a complete high-precision, rms-to-dc converter that can calculate the true rms value of any complex waveform. It provides integrated circuit rms-to-dc converters with high performance, accuracy, bandwidth and dynamic range comparable to discrete and modular designs. AD637 can calculate the true root mean square value, mean square value or absolute value of any complex AC (or AC plus DC) input waveform, and provide the equivalent DC output voltage. The true rms value of the waveform is directly related to the signal power, so it is more useful than the average rectified signal. The rms value of the statistical signal is related to the standard deviation of the signal.
The AD637 has an auxiliary dB output available to users. This takes the logarithm of the rms output signal as individual. Pins that allow direct measurement of decibels, with an effective range of 60 decibels of externally programmable reference current, allow the user to select a 0 decibel reference voltage to correspond to any level between 0.1V and 2.0V RMS.
In addition, when the AD637 power supply is turned off, the output will enter a high impedance state. This allows several AD637 to be tied together to form a wideband true rms multiplexer. The input circuit of AD637 is not protected by overload voltage exceeding the supply level. If the power supply voltage is lost, the input terminal will not be damaged by the input signal.
Precautions for using the module:
(1) The maximum input effective value amplitude of the detector module is 7Vrms. The maximum supply voltage is ±18V. Generally, if the effective value to be measured is relatively large, the supply voltage needs to be increased accordingly.
(2) Since the module is a precision device, in order to avoid unnecessary interference, it is recommended to use a linear power supply.
(3) It is recommended to use the SMA interface for the input signal. Poor contact or poor quality wires may cause signal attenuation or excessive noise, making the measurement inaccurate.
(4) The input end has SMA input or XH2.54-2PIN foolproof socket input, just choose one. (5) Due to the capacitive coupling relationship and the frequency characteristics of the chip, independent segment calibration is required below 200Hz and above 3MHz and the coupling capacitor needs to be amplified when it is lower than 200Hz to make the output detection effective value accurate. Refer to the test table for specific parameters.
(6) The response and amplitude of the detector module at different frequencies will be different, and there are differences between different modules. It is a normal phenomenon and not a problem of the module.
Details:
AD637 is a complete high precision, RMS DC converter, which can calculate the true RMS of any complex waveform. It provides an unprecedented performance accuracy, bandwidth and dynamic range of integrated circuit RMS DC converters comparable to discrete and modular designs. AD637 can calculate the true RMS, RMS or absolute value of any complex AC (or AC plus DC) input waveform and provide equivalent DC output voltage. The true RMS value of waveform is directly related to the signal power, so it is more useful than the average rectification signal. The RMS of statistical signals is correlated with the standard deviation of signals.
Excellent peak factor compensation allows the signal to be measured with a peak factor of up to 10, with an additional error of less than 1%. Broadband width permits the measurement of 200 mV RMS, input signals with frequencies up to 600 kHz, and input signals with frequencies up to 8 MHz and above 1V RMS.
AD637 race-band test meter needs independent sectional calibration above the coupling frequency MHz to make the RMS of output detection impossible for a chip to be flat in the whole frequency band. I hope the buyer will have a clear understanding of this characteristic.
If the detection is less than 200 Hz, the coupling capacitance should be increased, otherwise the low frequency attenuation will be severe, and then the low frequency output amplitude should be calibrated. The input of AD637 module must be coupled with capacitor, because this can avoid the introduction of DC component and make the output value of module inaccurate. On the other hand, the protection module is damaged by DC impulse, but adding large capacitor in low frequency band also has a bad effect, that is, charging time constant is too large, which depends on how the buyer chooses, specific use details, you can consult our shop technicians.
Above 2MHz, only need to calibrate the output amplitude for high frequency. No need to change input coupling capacitance
