characteristics of ideal op amp

Characteristics of ideal op amp

The ideal op-amp has the following characteristics

1.        voltage gain of an ideal op-amp is Infinite. ideal op-amp has infinite voltage gain because for finite output voltage, the voltage difference between the inverting and non-inverting terminals (also known as the differential input voltage) is nearly zero. (Due to their nature as voltage-gain devices, op amps require a high input impedance. According to Ohm’s law, V=IR, a very high impedance is required for a voltage drop to occur across the input. Preventing the loading effect is also crucial. The current draw would be high if the impedance were low.)

2.        Infinite input resistance R_i, so that almost any signal source can drive it and there is no loading of the proceeding stage.

3.        Zero output resistance R_o, so that the output can drive an infinite number of other devices. (for an ideal op-amp output impedance should be Zero)

4.        Zero output voltage, when input voltage is zero.

5.        An ideal op-amp requires infinite bandwidth because Any frequency signals from o to ∞ HZ can be amplified without attenuation.

6.        Infinite common mode rejection ratio, so that the output common mode noise voltage is zero.

7.        Slew rate value for an ideal op-amp Infinite, so that output voltage changes occur simultaneously with input voltage changes. (The rate at which an op-output amp’s can change in relation to its input is known as slew rate. It is determined by how much the voltage changes over time. The time delay is 0 for a perfect op-amp. The slew rate for an ideal op-amp is therefore infinite, according to the equation.)

8. CMRR value for an ideal op-amp is infinite. The ideal CMRR is infinite. 100 dB would be the typical value for CMRR. In other words, if an op amp had desired (i.e., differential) and common-mode signals at its input that were both of the same size, the common-mode signal would be 100 dB smaller than the desired signal at the output.