Millivolt/microvolt voltage amplifier signal amplifier AD623/AD620 instrumentation amplifier module

Product description:Dedicated instrumentation amplifier core, rail-to-rail output, high input impedance, high common-mode rejection ratio, low offset and drift, low noise, high closed-loop gain stability, and precision measurement/amplification.Module characteristics1. High-end dedicated instrumentation amplifier AD623 core with high precision and good linearity.2. Single power supply, support 3-5.5V power supply, easy to use!3. Integrated negative pressure generating module, dual power supply operation, easy to deal with negative signal / AC signal.4. Power input LC filtering, pure and stable, to ensure the stability of signal amplification.5. Built-in negative voltage generating module, only need a single power supply to operate with dual power supply, simplifying system design.6. Rail-to-rail output, the maximum output swing is +-VCC, far beyond the core products such as LM358/AD620 (only to VCC-1.5V)7. Magnification 2-1000 times adjustable, adapt to different applications, imported US bounds potentiometer, uniform resistance change, stable resistance, the price is higher than domestic potentiometer 10 times or more (inferior potentiometer often loose, open, beat, When the resistance is large, small, open, etc., it is impossible to ensure that the amplification factor is stable, and it is difficult to ensure accuracy.7. The module is simple, expandable, and detailed, convenient for secondary development.The main parametersAmplifier Type: Dedicated Instrumentation Amplifier AD623 CoreInput range: 0.5VCC (ie, the voltage between S+/S- is less than half of the supply voltage.)Output range: +-VCC (rail to rail)Magnification: 2-1000 times adjustable.Power consumption: 150uA (typical) 650uA (maximum)Power supply: 3-5.5VGain accuracy: 0.35% (G> 2) 0.10% (G = 2)Input offset voltage: 100-200uVInput offset drift: 1uv/°CCommon mode rejection ratio: 90dbGain bandwidth: 800KHZ.PCB size: 40*23mmPin description and wiring diagramIt is recommended to test the baby with a smaller magnification (eg 50/100 times) and then adjust to the desired multiple. Adjust the A++ knob clockwise to increase the magnification (up to 1000 times). When the maximum is adjusted, you can hear a slight click from the potentiometer, indicating that it has been adjusted to the end. It is also possible to use a resistor to fix the magnification so that the amplification value will be more stable.Precautions1. Some people refer to REF as the zeroing pin, so there is no problem, but the accuracy of the AD623 core is very high. The REF is directly grounded, and the output is very close to 0. Actually, no adjustment is needed. It is recommended to adjust the REF pin voltage only when the translation voltage is required.2. This shop uses the imported US bounds potentiometer, the regulation is uniform, stable, high reliability, the price is 10 times higher than the domestic potentiometer, non-common domestic potentiometer comparable.3. The offset voltage of the AD623 is 200 uv, which means that the maximum error of 200 uv can be generated on the input voltage. Therefore, if the input voltage is smaller, the initial error is larger, and the recommended signal should not be lower than 3 mv.4. The 3db gain bandwidth of AD623 is 800KHZ, that is, gain multiple * frequency = 800KHZ. Therefore, if the DC signal is amplified, it can be up to 1000 times. If it is amplified 800 times, the signal should not be higher than 1KHZ. If the amplification is 10 times, the signal should not be higher than 80KHZ, and so on, the higher the signal frequency, the greater the loss of amplification.5. The maximum adjustment range of the REF terminal should not be too large, otherwise it will affect the magnification.6. The output voltage range of the amplifier is limited by the supply voltage. The linear area of our AD623 module reaches ++-VCC. When the AD620/LM358 and other amplifiers are powered by +5v and -5V, the linearity is only between -3.6V and +3.6V.7. The REF pin of the AD623 can only pull up/down the output voltage. Normally grounded. When you need to use the REF pin to pull up or lower the output, you can change the voltage of this pin. However, in this case, it should be noted that the linear region of the magnification does not change due to the change of the 5-pin, and its maximum output does not exceed VCC.Instrumentation amplifier common senseVarious non-electrical measurements, usually converted by a sensor into a voltage (or current) signal, which is generally weak, with a minimum of 0.1μV, and a wide dynamic range, often with large common-mode interference voltages. . Therefore, most of the sensors need to be connected to the instrumentation amplifier. The main function is to perform precise voltage amplification on the sensor signal and suppress the common mode interference signal to improve the signal quality.In general signal amplification applications, a differential amplifier circuit is usually required to amplify the signal and acquire it. However, the basic differential amplifier circuit has poor precision, and the resistance matching problem is the main factor affecting the common mode rejection ratio. If a discrete operational amplifier is used as the measurement circuit, it is inevitable that there is a difference in resistance, and the cause of affecting the amplification accuracy of the entire signal is more complicated, thereby causing a reduction in the common mode rejection ratio and a nonlinearity of the gain. The integrated instrumentation amplifier fabricated by the post-mold process solves the above matching problem, and the instrumentation amplifying circuit has no such disadvantages and is widely used.Since the output impedance of the sensor is generally high, the output voltage amplitude is small, and the working environment is harsh, the instrument amplifier has special requirements compared with general general-purpose amplifiers, mainly in high input impedance and high common mode rejection. Ratio, low offset and drift, low noise, and high closed loop gain stability.General integrated instrumentation amplifiers have the following features(1) The input impedance is high, generally higher than 109Ω(2) Low bias current(3) Common mode rejection ratio is high(4) Balanced differential input(5) Good temperature characteristics(6) Adjustable gain(7) single-ended input