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Type: Posts; User: Robotduck

1. ## Thread: Potential Energy and Kinetic Energy of an Electron in an Energy Band diagram

by Robotduck
Replies
1
Views
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...

by Robotduck
Replies
4
Views
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...
3. ## Thread: Frequency compensation using Null resistor

by Robotduck
Replies
1
Views
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 ?
4. ## Thread: Power Supply Rejection Ratio

by Robotduck
Replies
1
Views
280

### [SOLVED]Closed: Power Supply Rejection Ratio

Why PSRR is calculated in unity gain configuration ?

by Robotduck
Replies
22
Views
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 ?

by Robotduck
Replies
22
Views
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...

by Robotduck
Replies
22
Views
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 ?

by Robotduck
Replies
22
Views
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...

by Robotduck
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...

by Robotduck
Replies
22
Views
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...
11. ## 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...

by Robotduck
Replies
2
Views
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...
13. ## 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 non-dominant pole is...
14. ## 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. ...
15. ## 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 ?
16. ## 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 ...
17. ## 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 ?
18. ## Thread: Resistance /impedance looking into the source / drain ?

by Robotduck
Replies
9
Views
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...
19. ## Thread: Resistance /impedance looking into the source / drain ?

by Robotduck
Replies
9
Views
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...
20. ## Thread: Resistance /impedance looking into the source / drain ?

by Robotduck
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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