Why do many people suggest using ADC chips to collect the output signal of bridge pressure sensors instead of using instrument amplifiers?

QWE4562009

Why do many people suggest using ADC chips to collect the output signal of bridge pressure sensors instead of using instrument amplifiers? [Copy link]

Why do many people suggest using ADC chips to collect the output signal of bridge pressure sensors instead of using instrument amplifiers to amplify the signal before ADC acquisition? However, early transmitters all used instrument operational amplifiers. When amplifying weak signals, noise interference will also be amplified synchronously. How to deal with this situation?

In the past few days, I have learned from many experts and have absorbed their opinions. They do not recommend using instrument amplifiers to amplify and collect such signals. Instead, use high-precision ADC chips with MCUs. (It is very difficult to make instrument amplifiers very stable. Since the emergence of σ-δ ADCs, as long as the ADC speed and input common-mode voltage range meet the requirements, instrument amplifiers must be excluded first. I have told you long ago that instrument amplifiers are unreliable and have too much drift. It is much more stable to use σδ ADCs, etc. I think this brother has a basis for his opinion. For example, the offset voltage, signal-to-noise ratio, common-mode interference, and differential-mode interference of op amps are not as strong as the anti-interference ability of digital ADC chips, right?)

After collecting the mV signal, the internal PGA amplifies it to several hundred mV and then samples it with the ADC chip. If the excitation voltage of the sensor is 3.3V, then the full-scale output voltage corresponding to the output sensitivity of 0.9-2.2mV/V is 2.91-7.26mV, and the internal gain of the ADC chip is 128 times, which is 380mV-929mV;

the pressure range of the sensor is 5kg, so if a 12-bit ADC chip is used, the resolution is 50000/4096=1.2g? (Is the pressure resolution calculated in that way?)


Now I have selected a CS32A010K8V7 ADC chip to form the function of the MCU, and the packaging, main frequency, and space all meet the initial product planning. Is there any brother who wants to complain after using it? RS, SGM, 3peak, and even ADI or TI are not used. They are all considering the brackets at the beginning of the text. If you are asked to choose, what will you choose?

What issues need to be considered when using ADC chips to collect such mV or even uV weak signals? Try to explain in detail based on your experience or problems you encounter, THX!