Hello friends welcome to engineering Funda family in this video I'll explain you parameters of operational amplifier here I'll cover each and every parameters of operational amplifier in great details let me tell you how many parameters that I'm going to cover in this video see first I'll explain you output offset voltage then I'll cover input offset voltage input offset current input bias current common mode gain common mode rejection ratio Supply voltage rejection ratio thermal drift and slow rate in this video so let us begin this video with first parameter of operational amplifier that is output offset voltage see output offset voltage is present at output so output offset voltage that is present at output without any input applied so here input that should be zero so we have non-inverting input and inverting input so both of this input that should be connected with ground at that time whatever output is appearing that is output offset voltage ideally output offset voltage should be zero why the reason is output is what gain into difference in between these two signal here if both of this terminal is connected with ground then output should be zero the reason is output is what gain into difference here difference is zero so gain into difference that is output it should be zero ideally but because of some imperfection there will be somewhat output that is output offset voltage see output offset voltage that that is happening because of two differential amplifier stages of op in my first video based on operational amplifier I have explained you block diagram see with input stage we have balanced differential amplifier and second stage is intermediate stage where we have unbalanced differential amplifier so here with this two differential amplifier output is based on difference right but as components are not identical in circuit there is always some output even though ideally difference is zero right so if you have V1 is equal to V2 then output should be zero or you can say as if V1 is equal to V2 is equals to 0 at the time output should be zero but because components are not identical there is always some output that is output offset voltage right so output offset voltage that is a voltage appearing at output provided input is grounded now second term is input offset voltage now see input offset voltage that is a voltage applied at input to make output offset voltage zero so here I have told you you see output offset voltage that is a voltage appearing at output provided input is grounded or you can say input is zero right now once you have output upset voltage then practically what we want practically we wanted to have zero output to get zero output if we apply some input over here then that is input offset voltage right so when non-inverting input and inverting input are grounded ideally output must be zero but practically due to two stages of differential amplifier small output appears at output to nullify this output voltage some voltage is required to be applied at either of the two inputs that is input offset voltage so to nullify output offset voltage we may need to give some input over here that is input upset voltage that input can be applied to V in Plus or that can be applied at V in minus right so in a way you can say to get zero output whatever input is required that is input offset voltage right see next term is input offset current see it is the algebraic difference between the current flowing into inverting and non-inverting terminal right so here you see we have non-inverting terminal this is inverting terminal with non-inverting terminal current is i+ and with inverted in terminal current is I minus so input offset current that is a difference in between i+ and I minus right so that is algebraic difference in between i+ and I minus see ideally i+ and I minus that should be zero so you can say input offset current that should be also zero why ideally it will be zero the reason is ideally input resistance of this OPM that has to be infinite if you have infinite input resistance then i+ and I minus will be zero right but practically input resistance or you can say input impedance of OPM is not infinite and as it is not infinite some current will be flowing over here at input here input offset current is difference in between i+ and I minus right see next definition that is input bias current see input bias current that is simply average of i+ n IUS so it is I + + IUS / 2 right ideally it has to be zero why the reason is ideally input impedence of op that has to be infinite so value of i+ and I minus that should be zero but practically input impedance cannot be infinite because of which i+ and I minus that will be obviously there so average of i+ and I minus that is I + + I minus by 2 which is input bias current IB right next comination that is common mode gain see common mode gain means what obviously gain is what output divide by input so what obviously here common mode output that is VM divide by common mode input that is vcm common mode input means common input voltage will be given to inverting and non-inverting terminal right so here VM / by vcm that is common mode gain so common mode gain should be zero ideally why the reason is for OPM output is gain into difference in between we this plus and minus right but here we are giving common signal so difference will be zero over here so ideally output should be zero but practically there will be some output VM so common mode gain that is vm/ vcm right now next definition that is common mode rejection ratio so it is simply a ratio of differential gain and common mode gain what is common mode gain common mode gain that is vm/ by vcm where vcm is common signal applied in between non-inverting and inverting terminal right so common mode gain is VM ID vcm what is differential gain differential gain that is a and that is based on that is based on our V out that is based on our V out divide by input difference input difference is v in plus input difference is v in plus minus V in minus right so differential gain differential gain that is output divide by input where input is difference in between non-inverting and inverting signal right so differential gain to common mode gain ratio that is CMR R ad / ACM see practically differential gain is having somewhat value but ideally differential gain should be infinite right so cmrr that should be as I have as possible Right see in competitive examination sometimes you may need to calculate cmrr based on some other parameters like Vio see Vio is what I have explained you that it is input offset voltage right B IO that is input offset voltage right so common mode rejection ratio that can be calculated based on input offset voltage divide by common mode voltage right but usually we calculate that based on differential gain divide by common mode gain right see next definition that is Supply voltage rejection ratio see Supply voltage rejection ratio that is quite interesting let me explain you that see s vrr is the change in opm's input offset voltage caused by variation in Supply voltages so with operational amplifier see we are applying Supply voltage VCC and minus ve so if you have some variation in VCC and ve in that situation you may have some variation in input offset voltage so Supply voltage rejection ratio is what it is change in input offset voltage with respect to change in Supply voltage right see many manufacturers are using this term with different name like some manufacturers are using term like psrr that is power supply rejection ratio so one should know power supply rejection ratio that is svrr only right and in some manufacturers data sheet they may write PSS that is power supply sensitivity so power supply sensitivity is what that is svrr only right that is change in input offset voltage with respect to change in Supply voltage right Supply voltage that is VCC that is VCC and minus ve right now see next definition that is thermal drift that is quite interesting you need to understand what is thermal drift see ideally parameters of operational amplifier like Vio I iio IB that stays constant viio means input offset voltage iio means input offset current IB means input bias current that should stay constant but practically they changes with respect to temperature the changes with respect to supply even the changes with respect to time if your ID IC is getting older in that case also these parameters are getting changed right so this parameters should stay constant but practically it changes with respect to Temperature Supply and time right usually we try to understand that with respect to temperature so you can say see thermal drift that is variation in temp variation in parameter with respect to variation in temperature like you see if you want to calculate thermal voltage drift then that is variation in input offset voltage with respect to variation in temperature if you want to calculate thermal drift current then that is variation in input offset current with respect to variation in temperature if you want to calculate thermal drift in input bias current then it is variation in bias current with respect to variation in temperature right usually you need to understand this in that sense see this variation should be as low as possible ideally it should be zero right so value of this voltage drift that will be there in terms of micro voltage per de CSUS and this drif in current that will be there in terms of pic amp per de C right but it should be as low as possible that one can say so thermal drift means what variation in parameter with respect to variation in temperature so variation in parameter can be there with many parameters like like it can be there with input offset voltage it can be there with input offset current it can be there with input bias current right see last definition that is slow rate slow rate explains you what it explains you how output is changing with respect to time so slow rate is defined as a maximum rate of change of output voltage per unit time usually we express that in terms of volts per microc so here you can observe see slow rate is what rate of change of output with respect to time and we need to consider this in terms of Maximum value right means maximum rate of change let me give you an example like if You observe see here I have shown you waveform so if I say I'm just giving input signal that is identical Square wave like this so here we have operational amplifier you see so with this OPM with this OPM if I give Square wave identical Square wave over here then output should be Amplified Square wave output should be Amplified Square view right so you see here my input is this my input is this which is square wave so my output should be Amplified Square wave right but you see what is happening here here my output is taking some time to reach to its Max maximum value right it it is taking some time to reach it to its maximum value so you can say here output is changing from this value to this value for which it is taking this much time so rate of change of voltage with respect to time that is L rate over here right if You observe here see here input that is falling from high to low so output also should fall from high to low but to fall it from high to low it is taking some time you see so slow rate over here that is rate of change of voltage with respect to time so slow rate that should be as high as possible slow rate explains you how fast OPM can react to any signal right so if slow rate is high output response will be faster over here right ideally you can say slow rate should be infinite I hope you have understood all the parameters which I have explained regarding operational amplifier still if anything that you like to share please note it down in comment section I'll be happy to help you thank you so much for watching this video