Math Problem Statement

Determine the output voltage of a differential amplifier for input voltages of 320µV and 260µV. The differential gain of the amplifier is 4000 and the value of CMRR is 200

Solution

To determine the output voltage VoV_o of a differential amplifier given the input voltages V1V_1 and V2V_2, the differential gain AdA_d, and the common-mode rejection ratio (CMRR), we can follow these steps:

  1. Convert the CMRR from dB to linear scale: CMRR=1020020=1010\text{CMRR} = 10^{\frac{200}{20}} = 10^{10}

  2. Calculate the common-mode gain AcmA_{cm}: The common-mode gain AcmA_{cm} can be derived from the relationship: CMRR=AdAcm\text{CMRR} = \frac{A_d}{A_{cm}} Therefore: Acm=AdCMRR=40001010=4×107A_{cm} = \frac{A_d}{\text{CMRR}} = \frac{4000}{10^{10}} = 4 \times 10^{-7}

  3. Calculate the common-mode voltage VcmV_{cm}: Vcm=V1+V22=320 µV+260 µV2=580 µV2=290 µVV_{cm} = \frac{V_1 + V_2}{2} = \frac{320\text{ µV} + 260\text{ µV}}{2} = \frac{580\text{ µV}}{2} = 290\text{ µV}

  4. Calculate the differential input voltage VdV_d: Vd=V2V1=260 µV320 µV=60 µVV_d = V_2 - V_1 = 260\text{ µV} - 320\text{ µV} = -60\text{ µV}

  5. Calculate the output voltage VoV_o: The output voltage is the sum of the differential output and the common-mode output: Vo=Ad×Vd+Acm×VcmV_o = A_d \times V_d + A_{cm} \times V_{cm}

    Substituting the values: Vo=(4000×60×106)+(4×107×290×106)V_o = (4000 \times -60 \times 10^{-6}) + (4 \times 10^{-7} \times 290 \times 10^{-6}) Vo=(4000×0.00006)+(4×107×0.00029)V_o = (4000 \times -0.00006) + (4 \times 10^{-7} \times 0.00029) Vo=0.24+1.16×1010V_o = -0.24 + 1.16 \times 10^{-10} Vo0.24 mVV_o \approx -0.24 \text{ mV}

Thus, the output voltage VoV_o is approximately 0.24 mV-0.24 \text{ mV}.

Do you want further details or have any questions?

Here are 8 relative questions that expand on the above information:

  1. How does a high CMRR value benefit the performance of a differential amplifier?
  2. What are the potential sources of common-mode signals in a differential amplifier circuit?
  3. How can you improve the CMRR of a differential amplifier?
  4. What role does the differential gain play in the overall performance of a differential amplifier?
  5. Can you describe how the output voltage would change if the input voltages were swapped?
  6. What are the practical applications of differential amplifiers in real-world circuits?
  7. How do temperature variations affect the performance of differential amplifiers?
  8. What is the impact of mismatched resistors in the input stage of a differential amplifier?

Tip: When solving amplifier problems, carefully consider the units of all quantities involved. Convert all values to a consistent unit system (e.g., volts, millivolts, microvolts) before performing calculations.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Differential Amplifiers
Operational Amplifiers

Formulas

Output voltage of a differential amplifier formula

Theorems

-

Suitable Grade Level

Advanced Engineering