LTspice Design -Electronics

User Generated

Zzrwan1234

Engineering

Description

Hi, can you help me doing this assignment?

You only have to do the simulation in (LTspice), and the calculation parts.

you do not have to write report.(I will do the report and the measurement ).

see the attachment.

thanks

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Design Project I EE 343 - Electronics II Select resistance values for the differential amplifier shown so that I = 2 mA and the single-ended differential gain is approximately 100 V/V. Measure the differential voltage gain as a function of frequency (sinusoidal input). Determine the 3 dB cutoff frequency. Also determine the common mode gain as a function of frequency and determine the 3 dB frequency. (This may be a zero in which case you will see the common-mode gain increase.) Use the differential and common-mode frequency responses to determine and graph (as a function of frequency) the CMRR in dB. Verify your results by finding all gains and cutoff frequencies through simulation. Your typewritten report should compare theoretical (design), simulated, and measured results. Important Notes 1) Be sure that all transistors are in the active range. The differential input needs to be less than approximately 18 mV to keep both Q1 and Q2 active. You can set up a voltage divider as shown below to get a small differential input. (This circuit will produce a small common-mode voltage, but since the common-mode gain is so small most of the output voltage can be assumed to be due to the differential gain.) The function generators in the Koch Center are very noisy. If you cannot get a clean signal use the cursor feature of the oscilloscope to estimate your voltage. 2) To measure the differential voltage gain you may need to measure vo1 and vo2 and use the math feature on the oscilloscope to find the difference. 3) Use the LM3045 ICs to obtain matched transistors. Q1 and Q2 are matched and emitter coupled. Use any two of Q3, Q4 or Q5 for the other matched pair. The emitter of Q5 (pin 13) is connected to the IC substrate layer and should be connected to the most negative voltage in the circuit (-12 V) even if Q5 is not used. V+ = + 12 V RC RC vo1 vi1 vo2 Q1 Q2 vi2 R IQ Q3 Q4 V- = - 12 V Differential Amplifier + vd – + – Differential Input vi1 vi1 vcm + – vi2 vi2 Common Mode Input
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Explanation & Answer

My final answer

Attached is my screenshot for drawing circuit in LT spice that includes the
differential amplifier, the differential input, and common mode input:

The simulated results in LT Spice are shown below:
For Differential Amplifier:

For Differential Input:

For Common-Mode Input:

The CMRR in dB is graphed using the common-mode frequency response is
shown below:

Similarly, The CMRR in dB is graphed using the differential is shown below:

In conclusion, by comparing the above the theoretical (design), simulated, and
measured results, it follows that they all agree with e...


Anonymous
Just what I was looking for! Super helpful.

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