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Type: Posts; User: Robotduck
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Yesterday, 04:04
 Replies
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 154
Closed: Potential Energy and Kinetic Energy of an Electron in an Energy Band diagram
Hi,
Can anyone explain the concept of K.E. and P.E. in a semiconductor?
Why Ec (lower level of Conduction Band) is considered as P.E. ? and why the Difference between the higher energy state and... 
21st April 2019, 18:03
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 4
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 464
Closed: Output Resistance of Amplifier with Feedback ( Series  shunt) Loading
Hi,
In the circuit attached, Ro of open loop circuit with feedback loading= ro (R2+R1)  RL.
How come ro is in parallel connection with other resistances. From the circuit it appears to be... 
16th April 2019, 19:49
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 1
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 236
[SOLVED]Closed: Frequency compensation using Null resistor
In the figure ( attached ):
In Razavi," If I1 is chosen with respect to ID9 such that Vgs13=Vgs9, then Vgs15=Vgs14." How ? 
16th April 2019, 16:08
Thread: Power Supply Rejection Ratio
by Robotduck Replies
 1
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 280
[SOLVED]Closed: Power Supply Rejection Ratio
Why PSRR is calculated in unity gain configuration ?

12th March 2019, 23:56
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 22
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 1,346
Closed: Re: Differential amplifier with current source load
I did not follow. With mismatch in RD, and ideal tail current source, and high frequency common mode noise ,why does not we see the disturbance on the single ended output ?

12th March 2019, 21:23
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 22
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 1,346
Closed: Differential amplifier with mismatch in Load resistance and ideal tail CS.
In the case of differential amplifier with ideal tail current source and mismatch in Rd, If we have a high frequency Commom mode noise, why does not it appear on the single ended output ? The single...

10th March 2019, 16:33
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 22
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 1,346
Closed: Re: Differential amplifier with current source load
Current through M1 and M3 is 0, So the current through M4 should also be zero, which means Vout= Vdd 0*ro4= Vdd, but how come it is 0 ?

10th March 2019, 16:17
 Replies
 22
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 1,346
Closed: Re: Differential amplifier with current source load
In large signal analysis for Differential amplifier with current source load, how the output voltage is 0 when Vin1 is more negative than vin2 ?
Current through M1 and M3 is 0, So the current... 
10th March 2019, 15:16
 Replies
 22
 Views
 1,346
Closed: Re: Differential amplifier with current source load
Yes, I use Razavi. Also for the common mode response ( in case of current mirror load), how can the voltages at node X and Y be equal ? Razavi explains this on page 149 with contradiction. I...

10th March 2019, 14:31
 Replies
 22
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 1,346
Closed: Differential amplifier with current source load
In a Differential amplifier with current source load (using current mirror), why the node P ( source node of both input transistors ) is considered approximately ac grounded in most of the books when...

17th February 2019, 12:46
Thread: Low and High Frequnecy Response
by Robotduck Replies
 11
 Views
 707
[SOLVED]Closed: Re: Low and High Frequnecy Response
"No, no. The first and second stage clearly constitute separate poles (at least two, as stated) which can't be summed up to a single pole. An single pole has 90° asymptotic phase lag, a double pole...

16th February 2019, 18:13
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 2
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 259
[SOLVED]Closed: Stable Vbias for Current source load/ Current Mirros
1 Why do we need a stable Vbias for current source load ?
2 Why can not we use a simple resistive network to bias a lets say for example NMOS current source load ?
3 Why do we need current... 
16th February 2019, 18:07
Thread: Low and High Frequnecy Response
by Robotduck Replies
 11
 Views
 707
[SOLVED]Closed: Re: Low and High Frequnecy Response
How can you tell that a particular circuit has n number of poles without doing any calculation? you mentioned ,"In a 1 stage cascoded amplifier which has at least 2 poles, the nondominant pole is...

14th February 2019, 19:16
Thread: Low and High Frequnecy Response
by Robotduck Replies
 11
 Views
 707
[SOLVED]Closed: Re: Low and High Frequnecy Response
Also, when we are doing the high frequency response, the dominant pole should not be at the output ? Why?
For example in a single stage cascade structure, the dominant pole lies at the output. ... 
13th February 2019, 16:30
Thread: Low and High Frequnecy Response
by Robotduck Replies
 11
 Views
 707
[SOLVED]Closed: Re: Low and High Frequnecy Response
In other words , what is the relationship between bandwidth and Time constant ?

12th February 2019, 20:39
Thread: Low and High Frequnecy Response
by Robotduck Replies
 11
 Views
 707
[SOLVED]Closed: Re: Low and High Frequnecy Response
First, my apologies for a confusing questions. I will try to be specific.
For example: We use OCTC ( Open circuit time constant method ) to get the high frequency response for amplifiers. I ... 
12th February 2019, 19:48
Thread: Low and High Frequnecy Response
by Robotduck Replies
 11
 Views
 707
[SOLVED]Closed: Low and High Frequnecy Response
Why do we use RC time constants to get the high and low frequency response? What is the physical explanation behind this ?

12th February 2019, 19:45
 Replies
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 589
[SOLVED]Closed: Re: Resistance /impedance looking into the source / drain ?
2)Since the capacitance effects are negligible .. can we use the dc test voltage source to get the resistance ?
3) you mean that In spice when we want to get the resistance looking into the drain... 
12th February 2019, 19:42
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 9
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 589
[SOLVED]Closed: Re: Resistance /impedance looking into the source / drain ?
Thank you so much .. a couple of more questions :
1) Since the capacitance effects are negligible in mid band, can we use dc test voltage source to get the resistance looking into the drain or... 
10th February 2019, 23:31
 Replies
 9
 Views
 589
[SOLVED]Closed: Resistance /impedance looking into the source / drain ?
1) Looking into the source or drain is it impedance or resistance ? I think it’s resistance because there are no capacitors in effect ( mid band). Is this correct ?
2) when we calculate the...
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