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86 Threads found on Differential Pair Design
This function can be realized with "differential pair" circuit.There are many information about this circuit and Barrie Gilbert ( Analog Guru ) has developed tons of circuits using with this basic one. If you search the articles of this great man and Chris Toumazou, you'll find very interesting and chic ideas.
135454 135455 1)Most opamp use nmos differential amp, but this one uses pmos. why? nmos is faster. 2)the third stage, buffer stage gain, and on the circuit, it shows 2 pmos(m8, m9). why? isn't it inverter is used as buffer? how's 2 pmos is a buffer?
Can any one help me in Understanding the OTA design attached in the picture below. I want to know the purpose of MC, MCN and MCP. I can understand MBN is for biasing but whats the purpose of MBP than? please anyone explain in detail. Thanx
Well the design constraints are the noise, speed, offset and power dissipation. For high speed, you will need minimum length transistors. The noise is mostly dominated by the input differential pair. So you have to do a PNOISE sim and keep increasing the width of input diff pair till you achieve your target. Similar exercise (...)
Why common centroid technique preferred for differential pair..? if you say it eliminates linear gradients then 1. Please explain what are the linear gradients and which type of mismatch category will it fall..(random/systematic).. 2. How exactly is this common centroid fighting against these linear gradients..? 3. If you can... please stick to
Dear all! I'm trying to amplify a differential signal what may vary from a few hundreds of micro-volts to tens of milli-volts. The main challenge is to design this amp in sub 1V and in sub 1?A. I designed OpAmp but won't work with such a low input voltage. The only way I found is to amplify separately these two (...)
How do you do load pull on a differential pair to know the optimum load impedance for the transistor? Do you just use one single transistor instead? A real design (either IC or discrete) will have some coupling between both output transistors, also a non-zero power supply impedance. So the impedance of the differential (...)
The long tailed pair is the basis for differnetial amplifier and its first stage. I have usually seen it constructed using pair of NPN transistors in common emitter configuration with their emitters feeding into a single emitter resistor. The common mode rejection ratio of this can be improved by connecting a current sink made using NPN at the emit
Hi, I already design a LNA schematic and layout, so far so good. Now, I plan to make it as a differential pair LNA... I had some idea about the schematic and test bench, but it does not work very good specially when it comes to layout. Can anybody introduce me the references I can use for finding the structure os schematic and also the (...)
Read the design guidelines RS-485 compliant drivers can be used for Rs-422 multidrop with one driver. THe termination resistors at each end of the bus match the differential impedance of the pair with active terminators ( ie. pull up/down or series to Vth
I'm routing a 4 layer board with a USB2.0 differential pair. The application note has an example stackup for a 4 layer FR-4 board as shown below (top image). The example includes trace width and spacing for a 90Ω differential pair. When I enter these parameters into either of the calculators I have, they both give (...)
I would be looking at folded cascode and using HV devices (like LDMOS) in the diff pair and the cascode guards. That will let you "pin" most of the critical voltages that have to slide across supply-driven and common-mode-driven ranges. But you need to be wary of input differential voltage max specs (which might force you to use thick gate MOS dev
Hi All, I am designing a two stage miller opamp (pmos input differential pair) in subthreshold region. I am using 32nm technology node. The parameters are given below: 1. Supply voltage = 1V 2. Bias Current = 200nA 3. Transistor Length = 160nm=(5 Lmin) There are no specific requirements but I have to just reduce power dissipation. I am (...)
Hi guys. I have to design the layout of the above mentioned ota. I am thinking on how layout the ota AMP. This OTA has PMOS input transistor. What I was thinking to do was to follow the schematic. That is: Interdigitize the cascode transistores that bias the diff. pair. Interdgtz the differential pair. (...)
Hello, I want to design a USB connection from a chip to a pcie header. The problem is the differential pins of header is in the opposite direction of that of chip. So I have to create a via and change the direction of one line to another layer in order to connect the two pins. The topology of the components cannot be changed. So I have to do so
Dear all, I tried to design a transmission line transformer as in attached image using differential pair, Can any one help me ,please? Thanks in advance,
Hi, To desiogn an op-Amp you must design proper biasing ciruits which is essential for the proper operation... For current mirror you have to find appropriate length which makes good mirroring of current... And it depends on which technology you are using.... Then choose somewhat bigger area for the differential input pair of the Op-Amp , (...)
Hi everyone, In my design, I have some special pairs of wires. The two signals in each pair should be totally matching with each other, having the same transmission delay like "differential signals". Is there any commands that I could use as timing constraint or routing options in Encounter? Thanks
Hello, Please I want to ask how to design an amplifier " transconductance Gm" with high Gm of 30m and high output resistance of 100K at the same time , I used folded casocde amplifier to satisfy high output resistance but because it was designed to be with high Gm , the current in the differential pair transiator and (...)
Hi All, I am designing an amplifier for extra-cellular neural recording. The input is given to a OSFET differential pair (M1 and M2 - input transistors). All the materials above the gate-oxide of the OSFET sensor is removed and exposed to the buffer solution where the neuron is kept. The gate voltage is set by using an electrode immersed (...)