What are the main parameters of integrated operational amplifiers?

2 What are the main parameters of integrated operational amplifiers?

Answer:
1) Open-loop differential mode voltage gain
The open-loop differential mode voltage gain is the DC differential mode gain of the integrated operational amplifier without external negative feedback, generally expressed in logarithms, in decibels.
2) Differential mode input resistance
It is the dynamic resistance seen from the two input terminals of the integrated operational amplifier, which will change with the ambient temperature and frequency. When selecting, we hope that the input resistance is as large as possible. The input resistance of the actual integrated operational amplifier is in the order of megohms.
3) Output resistance
When the integrated operational amplifier works in an open loop, the ratio of its output voltage change to its output current change. Its value can reflect the load capacity of the operational amplifier. It is usually required that the open-loop output resistance of the integrated operational amplifier is as small as possible, and the typical value is generally between tens and hundreds of ohms.
4) Common mode rejection ratio
It is defined as the ratio of the open-loop differential mode gain to the open-loop common mode gain, and is generally expressed in decibels. The common mode rejection ratio reflects the ability of the integrated operational amplifier to suppress common mode signals. The larger its value, the stronger the ability of the operational amplifier to suppress common mode interference.
5) Input offset voltage
For a rational (ideal) operational amplifier, when the input voltage u+=u-, the output voltage uo=0. However, in an actual operational amplifier, if uo=0 is to be achieved, a very small compensation voltage must be added to the input. This assumed voltage is the input offset voltage, which is generally in the order of millivolts, and the high-quality one is below 1mv. Obviously, the smaller it is, the better.
6) Input offset voltage temperature drift
The input offset voltage temperature drift represents the temperature coefficient of the input offset voltage and is an important indicator for measuring the temperature drift of the operational amplifier. Generally, the operational amplifier has a temperature coefficient of 10 to 20uV per degree, and the high-quality one is less than 0.5uV per degree. This indicator is often more important than the offset voltage, because the offset voltage can be artificially made equal to zero by adjusting the resistance value, but the temperature drift of the offset voltage cannot be adjusted to zero, and it may not even be reduced.
7) Input bias current
When the input voltage is zero, the arithmetic mean of the static base currents at the two input terminals of the integrated operational amplifier. This value mainly depends on the static collector of the integrated operational amplifier input and the β value of the input amplifier.
11) Input offset current
The input offset current is the difference between the static base currents at both ends of the integrated operational amplifier when the input voltage is zero, reflecting the degree of asymmetry of the input current of the differential amplifier. The smaller the value, the better.
12) Input offset current temperature drift
Represents the temperature coefficient of the input offset current. Generally, it is a few nanoamperes per degree, and the high-quality ones are only tens of picoamperes per degree.
13) Maximum common-mode input voltage
When the common-mode voltage applied to the input of the integrated operational amplifier exceeds a certain value, its common-mode rejection ratio will drop significantly, and even the integrated operational amplifier cannot maintain normal operation. This voltage is called the maximum common-mode input voltage. The size of this value reflects the size of the common-mode interference that the integrated operational amplifier can withstand.
14) Maximum differential input voltage
The maximum voltage difference allowed to be applied to the two inputs of the integrated operational amplifier is called the maximum differential input voltage. Its size is related to the structure of the input stage. When the applied voltage difference exceeds it, the PN junction of one side of the input stage transistor will reverse breakdown, causing the performance of the integrated operational amplifier to deteriorate significantly, or even cause permanent damage to the integrated operational amplifier.
15) Rated input voltage
Under the rated input current and nominal power supply voltage, the maximum output voltage peak value that the integrated operational amplifier can provide to ensure that the output waveform does not show obvious clipping or nonlinear distortion.
16) Static power consumption
Static power consumption is the total power consumed by the positive and negative power supplies of the integrated operational amplifier when there is no load and no input signal. The static power consumption of general-purpose integrated operational amplifiers is tens to hundreds of milliwatts, while that of low-power integrated operational amplifiers is only a few tenths of a milliwatt.