Question
Download Solution PDFThe Common Mode Rejection Ratio (CMRR) of an ideal OP-Amp is ________.
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFCMRR (Common mode rejection ratio) is defined as the ratio of differential-mode voltage gain (Ad) and the common-mode voltage gain (Ac).
Mathematically, this is expressed as:
\(CMRR = \frac{A_d}{A_c}\)
Ad = Differential gain
Ac = Common mode gain
Ideally, the common-mode gain of the Op--Amp should be zero., i.e. it must give a zero output for common input at both the inverting and non-inverting terminal. ∴ The CMRR of an ideal Op-Amp is infinity.
Ideal Characteristics of op-amp:
|
Characteristics Parameter |
Ideal value |
Practical value |
|
Voltage Gain (Av) |
∞ |
≈ 106 |
|
Input Resistance (Ri) |
∞ |
≈ 1 MΩ |
|
Output Resistance (R0) |
0 |
≈ 10 Ω to 100 Ω |
|
Bandwidth (B.W) |
∞ |
≈ 1 MHz |
|
Common mode rejection ratio (CMRR) |
∞ |
≈ 106 or 120 dB |
|
Slew Rate (S.R) |
∞ |
≈ 80 V/μs |
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