Sometimes I introduce a square wave inline with a power supply. I put them in series (one or both must have two terminals). Noise might be 1/10 of a volt.
Another method is mixed (additive)... power supply voltage enters through a low-ohm resistor. Noise signal enters through a parallel resistor. Both resistors are necessary.
The noise frequency should be deliberately chosen not to resonate with any harmonic generated within your circuit.
You can also do frequency domain PSRR by setting the AC properties
of the supply, or a secondary source with DC=0, AC=1. The HF PSRR
is often a key concern, telling you what your output filter must be
(or telling you that what's downstream, is "on its own" in conjunction
with real power source attributes like ripple.
Sometimes I introduce a square wave inline with a power supply. I put them in series (one or both must have two terminals). Noise might be 1/10 of a volt.
Another method is mixed (additive)... power supply voltage enters through a low-ohm resistor. Noise signal enters through a parallel resistor. Both resistors are necessary.
The noise frequency should be deliberately chosen not to resonate with any harmonic generated within your circuit.
Would a low-ohm resistor be series with the power supply? I got a bit confused due to the two resistors. Will there be two resistors?
Regarding frequency of noise, I did not use any inductors in my circuit to have resonance frequency. However, the parasitics will lead the amplifier to resonate. In practice, noise that comes from outside of the circuit (power supply, environmental, etc) will have a component in each frequency. Therefore, it might be possible to resonate the circuit in the resonant frequency. Would you please let me know if there is a logical justification for this matter?
In the CMOS book written by Behzad Razavi, it's been mentioned that any mismatch in the fabrication will cause the high-frequency noises to come from the power supply and can be amplified at the output of the amplifier if the tail current source has a high impedance. By reducing this impedance it can be solved. However, the CMRR would be degrading by reducing the impedance of the tail current source (REE). Do you have any suggestions to solve both problems?
In the CMOS book written by Behzad Razavi, it's been mentioned that any mismatch in the fabrication will cause the high-frequency noises to come from the power supply and can be amplified at the output of the amplifier if the tail current source has a high impedance. By reducing this impedance it can be solved. However, the CMRR would be degrading by reducing the impedance of the tail current source (REE). Do you have any suggestions to solve both problems?
This statement has no sense at all. How process mismatch will cause a noise from power supply ?? What is the relationship between them ??
I didn't understand, sorry.
Can you mention the page number of Razavi's book ?? (you hopefully talk about his famous book).
This statement has no sense at all. How process mismatch will cause a noise from power supply ?? What is the relationship between them ??
I didn't understand, sorry.
Can you mention the page number of Razavi's book ?? (you hopefully talk about his famous book).
I understand. Regarding reducing oscillation possibility, would you please let me know if you have any information concerning circuit and layout design to prevent oscillation?
I designed a 5-stage amplifier and connected the GND and VDD nodes of each stage. Now, when I reduce the gain, the oscillation is getting ruined. However, it is arising for the high voltage gain.
Regarding reducing oscillation possibility, would you please let me know if you have any information concerning circuit and layout design to prevent oscillation?
I designed a 5-stage amplifier and connected the GND and VDD nodes of each stage. Now, when I reduce the gain, the oscillation is getting ruined. However, it is arising for the high voltage gain.
I once made a stereo amplifier from a popular easy-to-use IC. Oscillations occurred when I turned the volume control way up. I had to try out different arrangements of my volume control potentiometer before I found one that worked. Don't know if oscillations arose from the power supply. Since then I read that op amps oscillate easily at high gain. Any number of causes can creep in.
I imagine certain amplifier types or amplifier IC's are better at hiding hum (voltage droops, etc.) in the power supply.