# Search results

1. ### Hspice waveform problem

Dear FvM, I increased the time (lower frequency), but it does not change. It is interesting that the same Netlist is simulated correctly in 2003 !!
2. ### Hspice waveform problem

Hello all, I simulated a circuit in HSpice 2008. The problem is that the output waveform is not accurate and is segmented. Please see the attached picture. I used smaller step in .tran analysis, but it does not correct: .tran 1n 2u This problem does not exist in Hspice 2003.
3. ### Monte Carlo simulation for W/L+variaition oercent

I want to do Monte Carlo simulation with Gaussian distribution for W/L (width/length) in HSPICE in 0.35um CMOS technology. How much variation percent should I consider ? and why?
4. ### Total Gm of OTA versus Frequency

Dear erikl, I understood what you mean, but I could not get the desired output. I have two questions: 1. My circuit input is differential and the output is sigle-ended. How do I apply the input? I applied "ac=1 sin(0 1 1meg)" as the input voltage (in open-loop config.). 2. I putted a...
5. ### Total Gm of OTA versus Frequency

How can I plot the total Gm of OTA circuit versus Frequency in HSPICE?
6. ### slew rate of OTA circuit

I am simulating a trans-conductance circuit (OTA). I want to obtain pulse response of the circuit. So I applied a square waveform voltage as the input, then I see the output current. My question is that may I compare the output current waveform with input voltage and then calculate the slew...
7. ### output current of differential pair (Transconductor)

Hello every one I want to calculate output current of differential pair circuit which is used as a OTA, but I could not obtain. I attached the related paper which claims From eq. (2)-(4) we can obtain the output current of eq. (5), unfortunately I could not obtain the result which they...

Dear LvW, I can not use differential pair amplifier, because my desired output voltage should be single ended (one node). In fact I want to realize the circuit which do what you said: Vout=0.5*(v1-v2) but not double ended.

1. So I can eliminate M2 and M6, and directly have V1 + V2 = Vou. right? 2. Do you use M0,1,2,3 for having more accuracy? ( cascode structure)

To have better accuracy I will use your original circuit. two question: 1. What do M2 and M6 do? 2. Why do you put M0,1,2,3? I guess you utilized them to have cascode structure and more accuracy, right? Should we connect all of their gate to GND?

Dear xiahanzh, Thanks for your reply. Could you please explain how it works? Is it possible to make it simpler? (less no. of transistors)

Hi every body, I need a simple analog circuit consist of only MOS transistors to do this: Vo=(V1+V2)/2 Where V1 and V2 are DC voltages less than 1v. By the way the V2 can be negative e.g. the circuit should be work for (V1-V2)/2. If you have idea by using resistors it works for me. I can...
13. ### How does this circuit work?

Dear LvW, Thanks for your reply, but as I said I know all of the expressions. I mean that how can I simulate the circuit (in Hspice)? I putted CMOS transistor level of OTAs, then if I apply iin1 ideally, since iin1= -io1, io1 should be equal to applied iin1, while it can be changed by its...
14. ### "Scientific publication" schematic drawing

I recommend microsoft visio which is an excellent tools to draw circuit. I use this software in my own published papers. Also you can try this website: www.digikey.com/schemeit‎
15. ### How does this circuit work?

I studied a paper attached with this post . I have a question about Fig. 3 which is also attached where a topology to realize multiplier circuit has been presented: How can we apply "iin1" to "EOTA1"? In the paper it is mentioned that "gmT1" has a direct proportion to "IBE1", when we change...
16. ### [SOLVED] transconductance measuring in the OTA simulation

Dear LvW, I want to draw the "gm" of the OTA circuit, since gm=Iout/(vin+ - vin-). Is it right ? If not, pls explain how I can draw the transcendence? In fact I want to demonstrate the linearity of the designed OTA by showing the gm curve.
17. ### CMOS OTA with low gm

any response ??
18. ### [SOLVED] transconductance measuring in the OTA simulation

any response ?
19. ### [SOLVED] transconductance measuring in the OTA simulation

How can I measure transconductance (gm) of a OTA ? or how may I draw transconductance of OTA in terms of input voltage variation? I want to divide the input voltage difference signal by output current, but it doesn't allow because when vin=0, the gm is infinite !!
20. ### CMOS OTA with low gm

Hi every body, I designed a new CMOS OTA which has high linearity as a voltage-to-current convertor. Also I utilized a technique in which "Iabc" has a direct proportion to "gm", i.e : Iabc=Kgm, where K consists of W/L of input transistors and some other constant parameters. By the way all of...