Episode #125 of the Stack Overflow podcast is here. We talk Tilde Club and mechanical keyboards. Listen now

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-

Filter by
Sorted by
Tagged with
2
votes
1answer
101 views

Contradicting ideas about differential signal route, confining fields vs Increasing impedance

By initial sense I think we must: keep pair intra-distance as close as possible for field cancellation. Fill surround of pair with GND plane and have via near to it to confine the fields, prevent ...
0
votes
2answers
63 views

Why Im getting shifted phase in the output voltage?

Why im getting shifted phase in the output voltage in this differential amplifier? and how can I eliminate this shifted phase? Second question is, I need to make a gain of 50 in the amplifier below, ...
-1
votes
1answer
91 views

Which load resistance is connected to generator U2?

I have this op amp and one of the questions says Which load resistance is connected to generator U2? This is my attempt but I can not confirm if it right. No it's not homework, it examples I'm ...
2
votes
2answers
148 views

RS485 termination

What is the recommended way for termination RS485? I read about couple of options to do this. If I don't want to do dissipate extra power, can I just put 120 Ohm resistor? I saw the follow ...
1
vote
1answer
286 views

Differential Pair Reference Plane Coupling

I am routing LVDS pair on a flex board. The signal is 264MHz. I used Saturn PCB design to calculate width and spacing between conductors. The targeted impedance for diff pair is 100 ohms, which is ...
0
votes
2answers
67 views

Why don't I get a signal on the load?

I don't get any signal on the load, what am I missing? Shouldn't it amplify the input signal? I have 50mA from the current mirror, the Vbe on Q10 and Q11 is around 0.75v
1
vote
0answers
59 views

Trying to view CM and DM components of a signal on a two channel digital scope screen

I want learn how to view the CM and DM components of a signal on a usual two channel scope. The reason for this to be able to verify whether a noise superimposed on a signal is CM orDM. Regarding my ...
0
votes
0answers
61 views

Differential Amplifier Exam Problem

I am lost with how to approach part C and D of the question. In fact, I need some intuition with how to tune a differential amplifier.
1
vote
1answer
66 views

When does differential signalling become necessary [closed]

Is there an industry rule of thumb or application note etc for when differential signalling becomes necessary for reliable communication? I'm thinking mainly in terms of distance and signal speed (...
0
votes
0answers
153 views

LVDS driver signals measurement

This is background: I have a self-made PCB, which is used to connect the camera via the CameraLink interface. When I connected everything together, it turns out that the camera is signalling me via ...
0
votes
2answers
82 views

Differential equation for current driven RC circuit

I need the differential equation for the following circuit for numerical integration purpose. It is driven by a time dependent current source. So the question is: How can I know \$U(t+dt)\$ given \$...
0
votes
1answer
131 views

Adding multiple differential signal

As I asked in "Adding multiple analog signal" before, I got that: for adding some signal together, we can only use op-amp, instead of lovely integrated circuit (ough). But the question arise because ...
0
votes
2answers
66 views

Mathematical model for differential signals and relation with reality

i have a question and i hope is not that strange. i spend some time asking myself how people came out with the mathematical model for differential signals and why is this better in this way?! to be ...
0
votes
2answers
204 views

Differential Opamp Strange Behavior

I have no answer for this strange opamp behavior. The circuit shown is from a typical nonisolated ,Non grid-tie inverter product (imagine H bridge Inverter). which has a common -ve high power circuit ...
0
votes
2answers
146 views

LIN to RS485 and back to LIN

I am currently communicating between two microcontrollers using a single pin and the LIN protocol over a short distance of 0.2m. Now I would like to extend the distance up to 5m by differentially ...
1
vote
0answers
59 views

Differential Clocking resistor and capacitor choices

I am working on generating a 2MHz differential clock signal for a DDS chip. I have been given a PCB with a design that I am unsure can work or what the thought was behind it. If anyone could help with ...
0
votes
0answers
56 views

Terminating Unidirectional Differential Signal

In a project I'm working on, I'm planning to use the SN75174 to send a signal through about 30m of twisted pair. This signal has a bitrate of around 1Mbps (it's a signal to drive WS2811 LEDs,) and ...
1
vote
1answer
396 views

Does LVDS always need 100 ohm differential impedance?

LVDS pairs need 100 ohms differential impedance. However, I am having trouble achieving that in my design. My design requires that the pairs travel over very thin flexible PCB, about 50mm total ...
1
vote
1answer
236 views

RS485 Waveform while Receiving Data

I was testing the RS485 Circuit, below is my circuit and I connect J5 to my PC using another RS485 to USB converter. In PC through Modscan software I was monitoring the polling and response, a twisted ...
0
votes
2answers
903 views

Virtual Short Concept in an Op-Amp

By virtue of the open-loop gain being infinity for an ideal op-amp, the two input terminals are said to be virtually shorted. Yet, the virtual short concept is only applied to op-amps in negative ...
2
votes
1answer
261 views

How to measure a 100 ohm differential signal on a spectrum analyzer?

I have a pair of 1.5V PCML differential signals coming out of an Altera Cyclone V GX FPGA, terminated on the FPGA in 100 ohms with common mode voltage = 0.65V (also provided on the chip). I need to ...
0
votes
2answers
129 views

Differential signal isolation

In differential signal circuits (specifically, RS-485), there is usually an isolation between the signal processing / generation stage (eg, microprocessor) and the line driver chip (something like a ...
2
votes
3answers
220 views

Differential to single ended audio signal

I'm working on an interface that will be connected instead of a speaker, input of my interface is differential, and output is single ended. I'm using the following schematics : R3 is the load to ...
1
vote
1answer
51 views

I need to find Vin max(Common Mode) and min(common mode) for given circuit.

please let me know how i can proceed with this circuit
0
votes
1answer
108 views

Why does LVDS (or any differential signaling for that matter) use a common mode voltage of 1.2V instead of 0V?

Why does LVDS (or any differential signaling for that matter) use a common mode voltage of 1.2V instead of 0V? Is there an easy way to shift the common mode voltage to 0V?
0
votes
1answer
61 views

What is a good way to add a programable offset to a diffential signal?

I have an AC coupled, ~10 MHz to 1 GHz, differential signal, with a programmable gain, coming from a detector. The signal contain pulses, and the DC-balance is poor but constant (even if my hand ...
0
votes
2answers
134 views

Does Differential Amplifier Emitter behave as ground in AC-analysis?

I am trying to solve various differential-amplifier homework problems for which I have the solution to study. For the simplicity of most problems we are able to neglect base-currents. Moreover, it ...
3
votes
1answer
254 views

Microstrip and CPWG transitions on PCB

I've been doing some simple RF boards as part of an internship in a lab, mainly to test particular ICs and prototyping, and mainly using coplanar waveguides. I've now been tasked with designing a ...
0
votes
1answer
231 views

How do you model differential inductor in LTspice?

I wonder how I can model a differential inductor in LTspice? I've an inductor that has half the turns on one side and the other half on the other side. It's intended to be used in a bridge tied ...
-1
votes
1answer
109 views

Need to convert unbalanced to differential input OPAMP

I have the following filter after the DAC chip (currently with unbalanced outputs) working very well, but I need now to change the DAC chip. The new source has differential outputs. Is there a ...
1
vote
1answer
52 views

LAN9512 differential wire routing on PCB

Using the Saturn PCB Tool (V7.05 - calculation method IPC-2152 - Etch Factor 1:1), in order to achieve a 90 ohm differential line with a single line impedance equal to 50 ohm for a design based on the ...
0
votes
1answer
97 views

OTA design, the Gm won't go down to zero

I'm trying to simulate a pseudo-differential OTA, but the the Gm vs Vin(differential) plot I obtain seems warped. The Gm won't go down to zero for large values of Vin. attached is the circuit ...
6
votes
1answer
108 views

GPS L5C Differential? Max Update Rate(bits/s|Hz)?

The differential GPS chips use L1 and L2C to calculate the ionospheric interference. With the new GPS satellites, the new band L5C is being deployed, and I am wondering about the following things: ...
0
votes
1answer
208 views

Differential amplifier and large signal analysis

Let's consider this circuit: Razavi makes the large signal analysis in the ideal case, that is with an ideal current generator. He shows that Ic1, Ic2, Vout1, Vout2 and (Vout1 - Vout2) are function ...
0
votes
2answers
157 views

Differential amplifier and differential signals in small signal analyses

I'm studying the differential amplifier on different books (Razavi and Sedra-Smith). I've understood how this circuit works, but I have some questions. When authors analyze this circuit (2 identical ...
1
vote
0answers
104 views

Differential amplifier circuit - output voltage

I have a homework problem. We have a differential amplifier circuit with two supply sources: \$V_{CC}=-V_{EE}=5V\$, that has two identical NPN transistors and three identical resistors. T2's base ...
3
votes
1answer
526 views

SPI with differential signaling

Standard SPI uses single-ended signals. Is it possible that a communication uses SPI protocol but the signals are physically LVDS?
0
votes
1answer
218 views

Input filter on differential amplifier input

Hi, I need to determine the transfer function Vout/Vin. A traditional differential amplifier transfer function without the 2.2uF on the input side would be G1 = (Z2/Z1)*Vin, where Z2 = (2.2uF // ...
0
votes
1answer
580 views

Single ended to differential conversion with voltage divider

Let's assume I have an AD-converter that expects a differential signal with zero common mode voltage and I want to connect a single ended signal source. If the AD has it's own isolated ground, couldn'...
0
votes
1answer
186 views

Differential amplifier circuit, problem with saturation

I have a homework problem regarding differential amplifier. We have a differential amplifier with symmetric supply (i.e. \$V_{CC}=-V_{EE}\$). Emitters are connected to a perfect current source \...
1
vote
1answer
52 views

Differential Amplifier constant output voltage

SE-Members, The past few days i've been figuring out why my circuit does not work. It is a simple differential amplifier with a gain of 2. The OpAmp is the "TLE2027CDR". My problem: The output voltage ...
0
votes
2answers
70 views

Finding Drain voltage of current mirror

Below I have a current mirror loaded differential amplifier. Can somebody please Just give me an idea of how to find the drain voltage, vd8. I am stuck because I don't see the relationships that can ...
3
votes
1answer
1k views

USB differential signal from single pin?

I'd like to make a device similar to the "Digispark", but what really bugs me about those (and most, if not all, V-USB designs, at least all I could find online), is the "waste" of a GPIO pin which is ...
0
votes
1answer
115 views

Differential amplifier - transfer characteristic question

I have a question regarding differential amplifier's transfer characteristic. If we have a circuit like this (note that \$V_{1}=-V_{2}\$, hence \$V_{cm}=0V\$): the transfer characteristic for \$V_{...
0
votes
1answer
60 views

Can one voltage output from OpAmp read with two ADC inputs?

this might be a little silly question, but please advise me. I am trying to use two photodiodes (one for the absorbance measurement and one for the source of the light as a reference) and the voltage ...
0
votes
1answer
145 views

Effects of increasing current on external noise and SNR for analog transmission

This is a conceptual question about long analog signal transmission exposed to capacitive coupling and EMI noise as shown in below figures: simulate this circuit – Schematic created using ...
0
votes
1answer
55 views

Effect of large capacitor for differential channel in S-parameter simulation

I have created a differential channel with Transmission line and interconnects for simulation. In the real channel, there is 100nF capacitor in between 2 transmission lines. Now the problem is when I ...
1
vote
2answers
101 views

Gain problem of inverting opamp

I'm implementing the circuit in the schematic on the breadboard. Difference of inputs V1 and V2 is about 5mV. Differential opamp has gain of 17,4 Inverting opamp has gain of 26 First problem: I ...
3
votes
2answers
126 views

differential routing without GND

I have task that I need to make adapter board which transforms gigabit ethernet connector RJ45 to another connector (not RJ45). I also have power connector to carry power one side to other. I need ...
-3
votes
1answer
68 views

Finding a range for a common mode signal

I have the question below Here is the figure they are talking about: (Text and images from: "Microelectronic Circuits" book by Sedra/Smith, 7th edition, chapter 9) Here are the answers to the ...