the GBP should be no change if and only if ur OP's dominant pole (assume single pole OP) is not affected by the loading cap. if u found the GBP changing with feedback caps, u should check ur dominant pole of ur OP , it must be shift away.noiseless said:Actually, it really depends. you can try use caps as feedback and use close loop do the analysis, you will find the GBP is changing.
Btrend said:u can connect a high resistance (e.g. 1GΩ) from X to GND.
I don't understand this,However, when you operate in closed loop, it is the components that determine the GBW of the circuit, in case they are not pure resistors.
1. the GND should be signal gnd, i.e. the DC level of VinJenifer_gao said:Thanks for everybody to reply me
Btrend said:u can connect a high resistance (e.g. 1GΩ) from X to GND.
Btrend, once I connect a high resistance from X to GND, can I do the simulation like the following setup: 1. apply a sinusoidal signal to the positive input node; 2.apply a specific bias voltage to the Vin node (like the way I did in my open loop simulation)
J
There is a trick in the pure capacitance feedback, because B(s) is called feedback transfer function, which depends on the feedback form. The B(s) is a constant only when the feedback is a series-shunt form. In this case the closed loop GBP is same as the open loop one. But if it is in the shunt-shunt form, the story becomes different
Btrend said:There is a trick in the pure capacitance feedback, because B(s) is called feedback transfer function, which depends on the feedback form. The B(s) is a constant only when the feedback is a series-shunt form. In this case the closed loop GBP is same as the open loop one. But if it is in the shunt-shunt form, the story becomes different
I don't understant these words.
Honestly speaking, I still don't understand clearly the 4-type feedback forms after so many years.
especially those series-series, series-shunt,shunt-shunt, shunt-series, what's main difference?
and what's the purpose to classfy them?
and why feedback of a series cap. is called series-shunt ? why ?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?