A Method of Testing Integrated Operational Amplifier Gain Characteristics

摘要

When integrated operational amplifier (Op amp) is tested under open-loop,output voltage keeps swinging.Especially for high gain integrated Op amp,oscillation is stronger due to severe drift This paper presents a method that using two aid amplifiers.The basic idea is testing the input signal and output signal of the integrated Op amp indirectly with two aid amplifiers to obtain the open-loop gain.The output signal is measured by aid amplifier ) (AD8055_1) which is a voltage follower in the circuit,and the input signal is tested by aid amplifier 2(AD80S5_2) which can amplify input signal tenfold.The results show that this method overcomes the measurement errors caused by zero drift and errors generated in testing small signals.All signals are analyzed precisely by network analyzer (NA).