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Questions tagged [differential]

Differential refers to any kind of signaling where the signal information is carried by two or more paths and both are required to properly reconstruct the signal. For example, USB D+ and D-

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458 views

Power planes splits effect on differential pairs routing

I'm routing a differential pair (rs485), and I'm wondering if I should avoid routing it above a power plane split. I read about the undesired effects that a ground plane split can have over those ...
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2answers
85 views

Differential pair impedance vs temperature

Does anyone know if the differential impedance, say of a PCIe bus, can be affected by really cold temperature, like -50 °C? I have a wifi card that does not work from -30 °C and colder. I am wondering ...
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75 views

Multiple differential amplifier

I have a small problem. I want to design a "multiple differential amplifier". With this, I mean a circuit that, given the inputs and outputs: simulate this circuit – Schematic created using ...
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1answer
284 views

Differential Amplifier with Global Negative Feedback

This question refers to audio amplifier design, using BJTs only. I am wondering how differential stage amplifier plays an important role in hi-fi audio amplifiers. According to this book (where ...
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1answer
54 views

Finding a suitable ADC driver (SE to DIFF VCM+-0.5V)

ADC:ADC3424 The input is specified to be differential with each input swinging symmetrically around +-0.5V (i.e. 2Vpp with 1V input and G=1). I can't seem to find a suitable ADC driver for this. TI ...
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1answer
675 views

AC coupling caps on USB interface [duplicate]

Does anyone know why AC coupling caps should be implemented in USB3 interface while it's not required in USB1/2? Anything to do with transmition speed, encode method?
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2answers
186 views

pnp differential input stage features

In one book I found that snippet. Can anyone explain me why the input may go below 0? There is a text with that pic: "The limit here is one diode drop below ground, at which point the base of Q3 will ...
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1answer
57 views

Circuit biasing problem for differential pair circuitry

How to bias this differential circuit correctly ? Additional Information: Vdd = 3.3V and This differential circuit is connected in negative feedback manner to a CMOS inverter. Note: this is not ...
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2answers
432 views

Measure Battery Current via Shunt

I'm working on a project where I'm measuring the current into/out of a battery (currents may be as high as approximately 150A, and I'm not aware of any hall effect devices that are continuously rated ...
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1answer
153 views

How can I make an amplifier such that its gain increase proportional to the input difference

I want to make an amplifier that has a gain which increase with the difference between the inputs. For example: If I have 2 volt difference between two input of the amplifier will have gain factor ...
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3answers
3k views

Understanding the necessity of Tail Current Source in Differential Amplifier/Simulation (SPICE)

My objective is to understand the need of the tail current source in a differential amplifier. So, to understand the significance of current source, I tried simulating the behavior with and without ...
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1answer
124 views

A question about differential measurement system

Below represents a differential measurement system for a data-acquisition: As far as I understood, in a differential measurement system neither the outputs of the signals nor the inputs to the ...
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1answer
52 views

Low Impedance Node Ground Approximation

In Microelectronic Circuits by Sedra/Smith, the authors perform small-signal analysis on a basic active-loaded MOS differential pair amplifier. In attempting to find the amplifier's short-circuit ...
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1k views

A basic level question about grounds in a differential amplifier circuit

As far as I know, voltage is a defined with respect to a common ground in circuits. So if there is a source and a receiver/amplifier; then they should have a common ground if we want to talk ...
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1answer
62 views

What is current in RL-circuit? [duplicate]

When t<0 Components in circuit are Jt = 3 A, R1 = R2 = 2 Ω, R3 = 4 Ω ja L = 10 H At t=0 switch K will be closed and i need to figure out what iL(t) is when t=4 So i tried to figure out iL(t) ...
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3answers
188 views

Differential Amplifier with Hard Limiting

I'm currently going through RF Microelectronics by Razavi. In chapter 3 he presents an example where the following signal is applied to a differential amplifier with a tail current source. $$Acos(...
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1answer
70 views

What is i(t) from circuit with differential equation?

When t<0 Components in circuit are Jt = 4 A, R1 = R2 = 2 Ω, R3 = 4 Ω ja L = 10 H At t=0 switch K will be closed and i need to figure out what iL(t) is when t=4 So i tried to figure out iL(t) ...
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3answers
336 views

What is the practical advantage of using mirrored signal outputs eventhough what matters is balancing the wires?

Some devices output differential outputs since both wires carry varying signals which are mirrored. Most devices on the other hand output one signal carrying and one GND wire. There is also ...
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1answer
177 views

POE power will not interfering on Data travelling on Ethernet , Whats the logic

I was design POE+ circuit , so I read lot of articles on POE(power over Ethernet) IEEE802.af 15.4W on PSE side , For 10/100 base T can use Alternative A method where it use to deliverer power on data ...
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2answers
2k views

Differential Pair Length Matching for DP83848I

I'm looking in the datasheet and layout guide of the DP838481 but I can't seem to find where it talks about length matching for the RX and TX differential pairs. It only mentions length matching for ...
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4answers
161 views

THS4521-HT: Op-Amp giving negative differential voltage

Can someone help to explain where I get wrong with this schematics? I use a differential op-amp THS4521 and want to measure the differential signal coming from a pressure sensor (transducer). The ...
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2answers
544 views

Remove DC offset from differential output, rotary encoder

Op-amp in my circuit is accepting differential sinusoidal signal, that swings around 0 V with 1 Vpp. It is configured as a comparator - swings to upper rail when the signal is positive and swing to ...
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1answer
465 views

DDR4 differential pair routing guideline

I have a question about the DDR4 trace routing on the server main board. For clock and DQS signals, are they both considered differential signals? I checked the Intel PDG; it shows that two specs ...
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2answers
4k views

Do USB Data Wires (D+/D-) have 90 ohm differential impedance and single ended 45 ohm impedance to ground and if so how is this made?

I understand that USB data transmission is done over various speeds where transmission line effects could come into play(max 480Mbps which means a max frequency that is much higher considering the ...
2
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1answer
270 views

Trans-impedance Amplifer with a Fully-Differential Amplifier

I'm designing a trans-impedance amplifier (TIA) for a fairly fast Avalanche Photodiode (APD), to amplify pulses of 1mA that last few nanosecond. I found a solution that have just enough bandwidth with ...
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4answers
103 views

Nonlinearities in Fully Differential Op Amp

I am trying to construct an amplifier circuit using a fully differential op amp (THS4503) to interface with an ADC (ADS5232). I will be reading a 0-5V sensor, which needs to be converted to a 1Vpp ...
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2answers
157 views

Differential amplifier and random signals

I would like to ask if I can amplify a random signal (picture 1 right hand) with a differential amplifier(picture 1 left hand) and how this will work.I know how the differential amplifier will work ...
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0answers
43 views

Variable differential amplifier

I made this scheme: simulate this circuit – Schematic created using CircuitLab Gain of this differential amplifier is constant and equal to 2. I would like to have possibility to substract ...
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1answer
285 views

BJT Emitter Degeneration Rπ

I am a bit confused about this differential base-emitter resistance. I has been said that r_pi doesn't have much influence on small signal input impedance, when CE with emitter degeneration is used. ...
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2answers
841 views

Differential ADC and Common Mode Voltage

I am trying to understand a little bit more about common mode voltage. I am working with a particular MCU, the TMS320F28377S, and it has a common mode voltage requirement for its positive and negative ...
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2answers
165 views

Interfacing an LVDS driver with an LVPECL receiver

I'm trying to understand how the below circuit allows interfacing LVDS levels with LVPECL levels. Assuming: Driver: Voh = 1.4V, Vol = 1V, Vcm = 1.2V Receiver: VBB = 2V After the transmission ...
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1answer
210 views

10BASE-T Layout Guidelines

How critical are parameters like trace length matching, differential impedance, vias, etc. when designing a 10BASE-T only application? I know that due to the reduced frequency, there is a larger ...
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2answers
187 views

RC integral and differential functions, Schmitt triggers. How does this circuit work?

I'd be happy if someone explained me why this circuit is the way it is; how does it work ? Also i would like to know what the value for C1 is. Taken from https://www.electroninvest.com/shop/items/...
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1answer
656 views

Single-ended to differential conversion and ADC application

I am not quite familiar with the things I am going to describe. So, I need some help over here. I want to integrate an AD4001 ADC at a board I currently design. The thing is that my analog signal is ...
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3answers
139 views

Questions about differential probes

(Q1) Can an active differential probe such as this Agilent N2752A be used in a single-ended way, i.e., with one of its inputs at the GND of a circuit? Understanding of course, that we have (a) 1/...
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1answer
2k views

Differential impedance of LVDS rules and tips?

I'm designing a interface PCB with I/O modules using ethernet. It is my first PCB with high speed communication, which is giving me a lot of worries. In the modules documentation it says that the ...
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4answers
343 views

Self-clocking driver / transceiver

I'm looking for a way to transmit a clock signal and data over a single line, perhaps using a self-clocking signal such as Manchester coding. The design I'm working on has a number of chained units, ...
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1answer
598 views

measurement of differential signals using multimeter

Though differential signals are measured through oscilloscope or differential probe, i tried measuring the signals through a multimeter out of curiosity and my observation was that when a voltage was ...
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1answer
393 views

What if you alter a differential amplifier by giving it a positive feedback rather than a negative feedback?

Figure 1 In the above Image 1, you see is a differential amplifier . It has a negative feedback as required. Now take a look at figure 2 below. Figure 2 Lets take a look at figure 2. Now that I ...
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1answer
238 views

Analyze Power Amp 2N3055 Wit Multi Diff amp [closed]

hi guys i have a problem on analyze on this circuit and i don't know how i resolve these 1- There Is a CE One Stage After Of Diff Amp But I Don't Know Why used This And Why Used Capacitor? 2-After ...
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2answers
88 views

What is the name of the maximum source to drain differential for a FET? [closed]

I'm working with high voltage, high power motor applications, and it's slipping me right now; what is the name for the maximum voltage between the drain and source of a FET? Edit: sorry for the ...
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1answer
58 views

Compute loss/inch for (differential) T-line from s-parameters?

I have the 4-port s-parameters of 2 PCB boards, where each board consists of a differential transmission-line with SMA connectors on either end. The only difference between the boards is their trace ...
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1answer
213 views

Using ADS1252 In DIfferential mode

I am trying to use ADS1252 ADC with Arduino. I got following schematic from git of a breakout board for ADS1252 Now there is only one pin dedicated to input signal whereas I want to use this board ...
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429 views

Gain of a differential amplifier with active load

Can anyone help me to find which is the type for the gain of this differential amplifier for common mode input.I had find that is Acm = 1/(gm3*2*ro5).Can anyone help me if this result is correct and ...
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1answer
96 views

Amplifier output goes haywire with load attached

I'm trying to create an op amp using FETs and BJTs. I need the gain to be over 500, currently without a load attached I have the gain about 1000. The input is a 0.05V sine wave, the output is ...
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2answers
148 views

Is there a need for reference plane for differential traces

Is there a need for a reference plane for differential traces. I have seen cases wherein people use unshielded FFC cable like ones from Wurth Electronik for a board to board connection of differential ...
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2answers
404 views

What mathematical equation can be used to represent the output of this differential amp circuit?

My lecturer has gave my class a number of circuits to analysis and currently I'm having trouble with the following circuit: I am familiar with how to calculate an equation for the standard ...
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1answer
253 views

iCE40 LVDS clock input

I'm trying to figure out how to correctly connect 200MHz LVDS oscillator (DSC1103CE1-200.0000T Datasheet) to ICE40LP1K-QN84 FPGA. After reading Lattice's guide to differential signals (Link) this is ...
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1answer
93 views

Sensing high differential voltages using operational amplifiers

Is there any solution to sense high differential voltages using operational amplifiers (without using resistive voltage divider) ? The input voltage range is [-30, 80] Volts. I've searched on all ...
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0answers
228 views

Current mirror and differential amplifier

Hi, In the attached figure, I am not sure how to formulate the relation between \$I_{ref}\$ and the DC currents through the four transistors \$Q_1-Q_4\$, given that \$I_{B1,2,3,4,5,6}\$ aren't ...