EEE Dept Engineering Topics List

Working Principle, Derivation, Observations , Waveform, Circuit Diagram, Solved Example Problems | Operational amplifier

Subject and UNIT: Linear Integrated Circuits: Unit II: Characteristics of Op-amp

As the name suggests the output of such an amplifier is inverted as compared to the input signal. The inverted output signal means having a phase shift of 180o as compared to the input signal.

Pin Diagram, Characteristics, Parameters, Symbol, Features

Subject and UNIT: Linear Integrated Circuits: Unit II: Characteristics of Op-amp

A very popular IC version of op-amp is μA741. The manufacturer of pA741 is Fairchild Semiconductor.

Subject and UNIT: Linear Integrated Circuits: Unit II: Characteristics of Op-amp

We know that the d.c. supply voltages applied to the op-amp are VCC and -VEE and the output varies linearity only between VCC and - VEE  Since gain is very large in open loop condition, the output voltage Vo is either at its positive saturation voltage (+ Vsat) or negative saturation voltage (- Vsat) as V1 > V2 or V2 > V1 respectively.

Subject and UNIT: Linear Integrated Circuits: Unit II: Characteristics of Op-amp

The graph of output voltage Vo plotted against the differential input voltage Vd ; assuming gain constant is called voltage transfer curve or characteristics of op-amp.

Subject and UNIT: Linear Integrated Circuits: Unit II: Characteristics of Op-amp

The important a.c. characteristics of op-amp are, 1. Slew rate 2. Frequency response

Subject and UNIT: Linear Integrated Circuits: Unit II: Characteristics of Op-amp

The important d.c. characteristics of op-amp are, 1. Input bias current (Ib), 2. foput offset current (Iios) 3. Input offset voltage (Vios), 4. Thermal drift

Power Supply Rejection Ratio, Slew Rate, Transient Response Rise Time with Solved Example Problems

Subject and UNIT: Linear Integrated Circuits: Unit II: Characteristics of Op-amp

Two other important op-amp parameters are the slew rate and the Power Supply Rejection Ratio (PSRR). Let us discuss and obtain the expressions for these two parameters.

Subject and UNIT: Linear Integrated Circuits: Unit II: Characteristics of Op-amp

Thus the d.c. voltage present at the output terminals when both the input terminals are grounded is called output offset voltage denoted as Voos.

Characteristics, Circuit Diagram, Solved Example Problems

Subject and UNIT: Linear Integrated Circuits: Unit II: Characteristics of Op-amp

The circuit which represents op-amp parameters in terms of physical components, for the analysis purpose is called equivalent circuit of an op-amp. The equivalent circuit of an op-amp is shown in the Fig. 2.11.1.

Ideal Op-amp Characteristics

Subject and UNIT: Linear Integrated Circuits: Unit II: Characteristics of Op-amp

The supply voltages of the op-amp are + VCC and - VEE. These supply voltage levels decide the maximum output voltage levels of the op-amp.

Working Principle, Mode Operation, Circuit Diagram, Solved Example Problems | Op-amp

Subject and UNIT: Linear Integrated Circuits: Unit II: Characteristics of Op-amp

In the a.c. analysis, we will calculate the differential gain Ad, common mode gain Ac, input resistance Ri and the output resistance R0 of the differential amplifier circuit, using the h-parameters.

Working Principle, Circuit Diagram, Solved Example Problems | Op-amp

Subject and UNIT: Linear Integrated Circuits: Unit II: Characteristics of Op-amp

The d.c. analysis means to obtain the operating point values i.e. ICQ and VCEQ for the transistors used.