Main parameters of integrated circuit operational amplifier

For the actual use of operational amplifiers, what is important is not to understand the internal circuit of the integrated operational amplifier, but to understand its characteristics, parameters and actual connection methods. The main parameters of the operational amplifier are:

(1) Input offset voltage

When the input voltage and the external resistance of the input terminal are 0Ω, in order to make the operational amplifier output offset voltage 0V, a DC compensation voltage must be added between the input terminals. This voltage is the input offset voltage UIO. The smaller the value of UIO, the better, generally The UIO of the operational amplifier is between 1 and 20 μV.

(2) Input offset current IIO

When the offset voltage of the op amp is 0, the difference between the static bias currents of the two input terminals is called the input offset current 0. The difference between the static bias currents of the two input terminals is called the input offset current IIO. IIO is actually an operational amplifier. The compensation current added to the two input terminals is as small as possible.

(3) Input bias current IIO

The average value of the static bias currents IB1 and IB2 of the inverting input terminal and the non-inverting input terminal of the operational amplifier is called the input bias current IB1.
The IiB of a bipolar operational amplifier is on the order of μA, and the IiB of a MOS operational amplifier is on the order of pA.
(4) Input offset voltage temperature coefficient dUIOt and input offset current temperature coefficient dHO
These two parameters are used to measure the temperature drift characteristics of the operational amplifier. The smaller the two indicators, the better.

(5) Open-loop differential mode voltage gain Aod

When the operational amplifier is operating in the linear region, the ratio of the output open circuit voltage uO to the input differential mode voltage Uid is called Aod. Aod> 0, and its value is between 60 ～ 180dB.

(6) Common mode rejection ratio KCMR

KCMR = | Aod / Aoc |, which is the absolute value of the ratio of the open-loop difference model gain of the dynamic amplifier to the open-loop common model gain, expressed in decibels. This value is generally between 80 and 180dB

The integrated circuit tester GT2200A is used to solve the test problems of these parameters, and the device can also be used to screen the devices. Details of equipment: /main/listproduct1423.html