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# Differential Pair

463 Threads found on edaboard.com: Differential Pair

## hspice cmos differential amplifier

I made a netlist of single ended diff amp but I am not getting right curve between input differential voltage and drain currents of differential pair mosfet M1 and M2. Can anyone tell me where I am wrong... .title'differential amplifier' .option acount=0 default acount=1 Vdd 6 0 DC 1.8V Vss 0 8 DC 1.8V c 5 0 1f (...)

## How to create a real custom vccs like a real device

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.

## connecting nodes of common centroid differential pair

Hi everyone! I am trying to layout a common centroid diff pair as below: GND D1 S D2 S D1 S D2 S D1 GND D2 S D1 S D2 S D1 S D2 GND GND D2 S D1 S D2 S D1 S D2 GND D1 S D2 S D1 S D2 S D1 GND but i need help connecting the gates and source and drains such that the layout becomes symmetric! can any one please post me a figure of your own layout

## [Moved]: fully differential OTA with CMFB

Hello Can anyone help me in designing a common mode feedback circuit (CMFB). I have applied a 100mV DC common mode input voltage at the input of a differential pair with no Ac signal. My fully differential amplifier output common mode DC voltage is 456mV at one end and 450mV DC voltage on the other end of the differential (...)

## This opamp design using pmos differential amp

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?

## Source deneration MOS differential pair

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

## Differential pair routing and stacking

Hi, I want to know if a PCB board is only having differential pairs to route and they are routed on top and bottom side of the board, then is it good practice to put two GROUND plane back to back (signal-ground-ground-signal) in PCB stack? If it is not then please suggest the right way to route the board and right stacking of PCB.

## Conventional dynamic comparator transistor sizing

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 needs to be (...)

## Common centroid for differential pair..?

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

## CAN vs LIN communication

The answer is simple and can be given by thinking quite a bit. Full duplex is only possible with separate communication channels for RX and TX, as e.g. RS-232 has it. Neither LIN (single line) nor CAN (single differential pair) does provide it.

## Fully differential op amp offset nulling

Means you have the amplifier as component with four external resistors defining the gain? You might use current sources to inject an offset current to the inputs, e.g. a differential pair.

## Very Low Differential voltage amplification

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 differential signals (ie. with

## Differential Power Amplifier

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 stage is d

## Differential Pair and ICMR

Hello guys, I was reading the 2-stage opamp chapter in Sedra&Smith book when I came across with the ICMR concept. The input diff. pair is a PMOS. They say in there Consider the situation when the two input terminals are tied together and connected to a voltage Vicm. The lowest value of Vicm has to be sufficiently large to keep Q1 and Q2 i

## Equivalent Level Shifters ICs

At the higher data rates I recommend you move to the LVDS standard, for which there are CMOS<>LVDS chips for almost any supply voltage you'd like (at least, from 1.8V through 5V). A transmitter at one end (say, 5V), a 100-ohm differential wire pair and a receiver at the other (say, 3.3V). I have found in some ASIC designs that 80MHz with a "5mA

## what is CAN bus-off state ?

An off state, more accurately called recessive state, is zero volts across the differential pair CANH and CANL, as long as there is a 120 ohm termination resistor.

## Routing Differential signals

Hi All, Is it possible to route differential signals in orcad 9.2 layout. If yes, please tell me how to do in Orcad 9.2 Layout.

## Need Help with Differential Pair Excitation in HFSS

Hello Everyone, I am trying to simulate a multilayer structure in HFSS 13.0. It is made up of copper planes (PCBs) at the top and bottom and 5 layers of different dielectric materials in between. There are two pairs of cylindrical slots one at the top and one at the bottom, through which differential excitation is to be provided. The differentia

## capacitance water level sensor

Most likely you have a large common mode noise interfering with a differential current source, sense. Try a large CM balun or ferrite sleeve or twin coupled choke to the twisted pair to raise CM impedance and thus CMRR but keep DM impedance relatively low compared to Zc(f) If that fails, reduce area of loop with a smaller gap . water has a diele

## Differential pair routing

I am a bit lost about how to establish the parameters to establish differential pair routing. I am currently trying to route several differential pair and I am a bit new to this. I have searched online some tutorial but I don't find any really explaining **easily and out of the theory** with sipmple succession of steps about (...)

## what are purposes of this 2 additional transistors next to the differential pair?

One differential pair allows the input to reach and work well at up to Vdd and the opposite differential pair allows the input to reach and work well at down to Vss. It is called a "rail-to-rail input".

## [Moved]: What difference between folded cascode and differential pair?

I couldn't notice the difference. It looks like folded cascode almost same as differential pair.

## Creating long tailed pair differential amplifier using NPN vs PNP

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

## Can i drive SPI Signal to long distance

What is long distance for you? You can e.g. translate the SPI signals to RS-422 differential signals, transmitted through twisted pair cables.

## Differential to Single Ended with transformer?

I have a RF switch that I would like to select between two clocks (125MHz and 150MHz). The clocks are both LVPECL signals, 100ohm diff pairs. The SP2T inputs are 50ohm single ended. Can I use a balun for the Diff to SE transform? What kind of termination would I need on the diff pair side? 100 ohm resistor? W What is going to happen to the s

## LNA differential pair design

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 test benc

## Zero crossing detection with common ground

There is an uncertainty of signal integrity if there is either a common mode noise with an imbalanced pair of signals or a differential noise between the different grounds which may be coupled to each signal. Although this is a simple analog detector, the probability of error depends directly on the SNR and discriminator method. Thus you must def

## Operating point in MOSFET differential pair with current mirror and current source

... For proper operating point a large inductor i.e. 10^9 should be connected at output with a voltage source. I am confused what changes will this bring to the circuit simulation. As said in the following text (by Tietze-Schenk), this is a method for simulation to keep the outputs (of a fully differential

in this circuit, how could i apply an appropriate DC bias to keep all 12 MOSFETs in saturation? i heard there should be an equation to calculate? i'm quite confused! 122859 - - - Updated - - - i'm sorry, how could i get the ICMR value then put it into the Vin+, Vin- then get

I can use only one port and I put it between resonator and negative resistance pair.Use "OscPort2 (differential Oscillator Port)" not "OscPort (Grounded Oscillator Port)". However you don't need to use "OscPort" or "OscPort2" at all. Sp

## [moved] differential signalling in RS 485

What is meant by differential signalling in RS 485?

Hello, I am simulating differential pair with resistive load and another with active load with differential output, I have read onlone and razavi book that Active load improves CMRR and also differential gain, but reason for this is not mentioned. can anyone guide me why we replace load resistors with MOS loads ? (...)

## Simple distortion model for modern MOSFET

Hi, Using the square law model, one can derive the distortion of a differential pair using NMOS as: HD3 = 1/32 (vi/Vov)^2 I successfully used this approximation for an 180nm process and it was still reasonably accurate. Now for a 28nm process, this formula seems to be unuseable. As example, I use vin=1mV. Vov is not very well def

## What type of connector for differential signal

It depends on your clock rate and allowed jitter and distance. Dual stripline to RJ45 to Cat5 thru Cat7. Balanced differential offers the best SNR with good common mode rejection.

## [moved] Communication Problem RS-485 MASTER and SLAVE

Hi, To hardware: * RS485 is a two wire bus, differential signalling, plus ground signal. * It needs differential pair wiring with a wave impedance of about 120 Ohms. * All devices are connected in a string ==> No star wiring. * The master does not need tof be connected at one end, it may be placed anywhere in the bus, * Both bus ends (...)

## MOSFET Differential Pair (Analysis)

Hello, I am testing a MOSFET differential pair with resisitive load and as well as Active (MOS) loads. In DC simulation with resistors as load I can calculate the differential Output voltages and Currents but with MOS loads I also want to calculate the differential output (vout1 vout2) which sis not showing a proper (...)

## monitor each Cell voltage in series/parallel battery

You have 4 nodes to measure to compute 6 differential values or simply the V/2 error in 3 nodes. This tells if each one of two is imbalanced and not each pair, Generally cell matching is 1% of 1.5V for new batteries, but since Vmax-Vmin is around 1.0Volt or 11.5 to 12.5 with some load for near 0 to 100% SOC, the 1% imbalance is equivalent to 8% SoC

## Line Driver with 3-STATE Outputs

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

## TEX-ELZ insulated copper wire for transformer windings....only rated to 1000vrms?

The table & footnotes indicate they are rated for 1000 Vrms but tested for 1 minute at 3kV and as a differential pair up to 6kV. Regarding isolation tests, 1 layer of kapton with give additional to secondary from primary and is the essential added insulation barrier especially when the secondary is also grounded ( worst case stress ) HV insulat

## Attaching a crystal oscillator to a transformer

To avoid DC magnetization of core , two cascaded inverting buffers capable of driving load in differential mode ; pls specify load and f.

The standard CAN interface uses differential signalling, a current transformer around the CAN twisted pair will ideally receive no signal. You would have to sense the (small) dipole field involved with the non-zero distance of the twisted pair wires. Also the bus state is primarly represented by voltage not current. Signal current will be (...)

## differential pair trace impedance calculations

dear friends I want to route 100 ohm differential pairs of LAN on two layer pcb ( 1.6mm pcb thickness ) with 8 mil trace width, 8 mil trace spacing , 1.4 mil trace thickness.(dielectric constant Dk=4.3 as fr4 material with 1.6 mm is used) can anybody help me how to calculate 100 ohm impedance with above data......

## Why should we go for differential pair as compared to the pseudo differential pair???

I wanted to know that why do we go for differential pair input as compared to the pseudo pseudo differential pair??? I know from various discussions that my common mode rejection will be poor in pseudo differential but I wanted to know the comparison w.r.t other parameters like slew rate and settling time (...)

## 4 layer stackup differential pair for USB, Impedance question

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 (...)

## What is the difference between these amplifier types?

Opamp: One differential input pair, one single ended output, very high open loop gain (practically infinite at DC) differential amps: In a technical sense, Opamps are differential amplifiers. But when an amplifier is referred to as "differential" it's usually referring to differential (...)

## LVDS transfer via 50-Ohm (single ended) cable

1) Is this 50-Ohm cable really usefull for my application? It's a valid option. You also find PCIe test boards connecting 100 ohm differential pairs through two SMA connectors. What Pin-assingment scheme I should use? Always 2 neighboring wires for 1 LVDS pair and then one wire free connected to GND? I don't think

## PCIe specification questions

1. Are isolation capacitors on the Tx lines a must? What is the motivation behind the DC isolation? - Yes, These capacitors are must. In PCIE system, This is few lines from Spec "The PCI Express add-in card and system board shall incorporate AC coupling capacitors on the Transmitter differential pair. This is to ensure blocking of the DC path b

## cutoff frequency of pair differential MOS

Maybe if you knew the device attributes and the entire circuit topology you could get close, but with what you offer... no. The load is as important as the diff pair, to begin with. A differential pair without a load is a useless thing.

## HELP. Design a High Voltage OpAmp

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

## Why doesn't my NE5532 work in this simple configuration?

NE5532 has a pair of parallel 'head to toe' diodes across it's inputs, if you exceed about 0.6 differential voltage across them the diodes will conduct and seriously screw up the output and input voltages! Brian.