Download Parameters of OP-AMP

Parameters of OP-AMP
M.S.P.V.L Polytechnic College,
Pavoorchatram.
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Circuit Symbols of OP-AMP
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Parameters of OP-AMP
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Input offset voltage
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Input offset current
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Input BIAS current
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Input capacitance Ci
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Common mode rejection ratio
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Supply voltage rejection ratio
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Slew rate
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Gain bandwidth product
Large signal voltage gain
Output voltage swing
Differential input resistance Ri
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Input offset voltage

Input offset voltage is the voltage that must be applied between
the two input terminals of an op-amp to null the output.

Typical value of 741 IC is 6mV dc.
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Input offset voltage
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Input offset current

The algebraic difference between the current in the inverting
and non inverting terminal is known as the input offset
current Iio.

As the matching between two terminals increases,the difference
between IB1 and IB2 become smaller.

Typical value for 741 IC is 200mA(max).
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Input offset current
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Input BIAS current

IB is the average current flows in the Inverting and Non-Inverting
terminal of OP-AMP.
IB = (IB1 + IB2 )/2

Typical value for 741 is 500mA
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Input BIAS current
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Large Signal voltage Gain

It is the ratio of the output voltage and the differential input
voltage.
A= Output voltage/Differential input
= Vo/Vid

Typical value for 741 IC is 200,000.
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Large Signal voltage Gain
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Output Voltage Swing

This parameter indicates the values of positive and negative
saturation voltage of the op- amp.

For 741IC,it is +13 and -13V.
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Output Voltage Swing
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Differential Input Resistance Ri

Differential input resistance Ri is the equivalent resistance that
can be measured at either the inverting or non-inverting
input terminals with the other terminal connected to ground.

Typical value for 741 IC is 2 mega ohm.
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Differential Input Resistance Ri
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Input Capacitance Ci

Input capacitance is the equivalent capacitance that can be
measured at either the inverting or non-inverting input
terminal with the other terminal connected to ground.

Typical value for a 741 IC is 1.4 pF.
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Input Capacitance Ci
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Common Mode Rejection Ratio

When the same voltage is applied to both the input terminals
the voltage is called a common mode voltage Vcm and the opamp is said to be operating in the common mode configuration

CMRR is defined as the ratio of the differential voltage gain to
common mode gain.
CMRR = Ad/Acm
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Common Mode Rejection Ratio
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Supply Voltage Rejection Ratio

The change in an op-amps input offset voltage Vio caused by
variations in the supply voltage is called the SVRR.

It is expressed in microvolts per volt or in decibels.
SR= ΔVio/ΔV

Typical value for a 741IC is 150μV/V
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Supply Voltage Rejection Ratio
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Slew Rate

Slew rate is defined as the maximum rate of change of output
voltage per unit of time and is expressed as volt per micro
second.
SR=(|dVo|/|ds|)max ie V\μs
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Slew Rate
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Gain Bandwidth Product

The gain bandwidth product(GB) is the bandwidth of the op-
amp when the voltage gain is 1.

Typical value for 741 IC is 1MHz.
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Gain Bandwidth Product
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The End
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