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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I2C over long distance with RJ11 CAT3 cable: how EMI noise will effect differential (but not twisted) pair wires
I have several nodes with Cat3 RJ11 cable in my office. I need to do an I2C communication between several nodes over + 20m and read about the PCA9615 driver. Unfortunately, the Cat3 RJ11 cable has ...
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1answer
72 views
ICs on opposite sides of a PCB
I am relatively new to PCB design and circuits in general. I am routing my first 4 layer board now and I am wondering about placing ICs on top of each other on opposite sides of the PCB. The ICs in ...
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43 views
Driving optocoupler by a line receiver
I wanna drive TLP350 by a line receiver AM26LS32. I employed scheme 1, however, there was no signal on output.
I found in line receiver datasheet that the current sign is negative so it is likely to ...
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2answers
58 views
What is Ethernet diff. pair referenced to between connector and magnetics
This is a little bit confusing part. I clearly understand that in ethernet cable fields are coupled between wires of differential pair. On PCB on IC/PHY side it is also known that differential pair ...
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37 views
Differential Pair active load contradiction
I'm confused about one current-based explanation for why the active current mirror restores a differential pair's gain by letting each differential input reinforce the other. The explanation (from ...
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1answer
27 views
Differential transceiver SN65C1167
I have a question about a differential transceiver.
In my application I am using a MCU to generate PWM signals for a gate driver board (CGD1200HB2P-BM2). This board, however, needs a diffierential PWM ...
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3answers
81 views
Differential (RS-422) vs current mode signaling in noisy environments
I’m building some automation equipment for my shop that will be used in extreme noise environments (plasma cutting and TIG welding nearby, for example) and I’m trying to come up with the best ...
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37 views
Differential integrator vs standard
I want to integrate/amplify a very small signal (relatively short pulses of 100ns to 4ms, necessitate high-bandwidth components minimum 40MHz+). The capacitors will be switched (shorted) when not in ...
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23 views
Finite CMRR even with ideal tail current source (body effect)
In Razavi's Design of Analog CMOS Integrated Circuits 2nd edition page 123, the diff-pair below is included with a comment about how even if the tail current source is infinite, if the transistor pair ...
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1answer
28 views
Referencing multiple differential pairs to ground before analog multiplexer
Yesterday I asked how to properly reference a differential signal (in my case from a current transformer) to ground, and got told that the impedance to ground should be matched at the location where ...
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53 views
Create differential signal from single ended encoder
I have a problem with the output of an DC motor encoder feedback. I have an 5v single ended encoder (AB signal), but my control needs an differential signal. I am not sure how to do this as I have no ...
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31 views
Differential pair linear range
If I increase the tail current, will the linear range of differential pair (range of Vid when both transistors are on) become larger or smaller?
According to this formula, linear range will increase ...
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42 views
Best way to combine different frequency sinusoids to simulate noise?
I'm designing a differential amplifier to remove noise from a signal, and I'm trying to verify my design by simulating a noisy input, but I'm not sure how to do this. The diagram below is roughly what ...
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49 views
How can I do a buffer to those circuit?
I need to project a amplifier with 3 stages. First, a differencial pair with active load and current mirror. Second, a cascode and third, a buffer. I'm using BC547(npn) for differencial pair and ...
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19 views
Level Translation Clarification (LVPECL and LVDS)
I am trying to understand something about level translation. I am sure I am probably misunderstanding something basic, so I'm hoping you can help me understand.
I am trying to convert a LVPECL signal ...
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37 views
Differential to Single-Ended Converter + Common-mode Shift + Sallen-Key Filter (Is one Stage Possible?)
I have a differential signal that needs to be conditioned as follows:
Convert from differential to single-ended.
Filter with a 3rd order Sallen-Key filter
Common-mode shift into an single-ended, ...
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1answer
69 views
differential ADC full scale signal
I have the ADS4249 differential ADC from Texas Instruments here is the datasheet.
On page 55 it says:
For a full-scale differential input, each input pin (INP and INM) must swing symmetrically ...
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17 views
How to calculate a differential ADCs resolution
I have a differential ADC with two internal reference voltages. The bottom voltage is 1V the top voltage is 3V with a 14bit resolution. I want to calculate the resolution in V.
For a single ended ADC ...
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1answer
55 views
Top layer vs mid layer for high speed ADC signal routing
Assuming we have an analog differential signal trace that we must route from the connector to,say, an ADC (24 bit or 32 bit kind as I don't think lower resolution ones are affected by this.) What we ...
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1answer
30 views
Common mode filtering a shunt: “active” vs. “passive” strategies (diff. amp vs. common mode choke)
If you are trying to observe a relative small voltage across a shunt resistor and you are finding common mode noise interference induced in the signal, in what cases would you choose to use something ...
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1answer
26 views
Differential amplifier with a notch on output
This circuit is used to:
Read an encoder output and level shift it to 3V3 from 24V;
Convert a 0-10V input signal to 0-3V3;
Both points 1 and 2 should be usable at the same time. Point 2 works ...
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2answers
73 views
Op-amp comparator and differential signals
On a board I'm working with, there's a 120 ohm termination resistor. I need to measure the voltage across it and compare it against a reference voltage.
I'm wondering how to make the connections.
The ...
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314 views
Common ground in low side current sensing
I've asked this question a while back and user/Transistor told me that the circuit will be floating and drift without a common ground, he suggested a virtual ground. but in this case we already have a ...
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2answers
66 views
What is the role of the differential amplifier in a delta sigma converter?
A differential amplifier amplifies the difference between the two input voltages but suppresses any voltage common to the two inputs. Based on this scheme
the differential amplifier is substracting ...
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65 views
What is Input Impedance Mismatching of differential Operational Amplifier?
I am new to design differential op-amp.
I am not sure if my circuit will experience input impedance mismatching.
Can anyone explain how input impedance mismatching will happen in differential op-amp? ...
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44 views
Measuring a divided differential voltage into a single ended DAQ
I am looking to log a high sped voltage (20 kHz) +-60 V, into a single ended DAQ at +- 5V.
Is the following circuit a good example of accurately measuring a differential voltage or is it overly ...
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2answers
82 views
Difference amplifier using Op-amp in LT-SPICE
I am simulating differnce amplifier in LTSPICE as shown below, i have used 400V DC source with 10V sin wave and then i am dividing it by factor of 80 and them taking differece with 5V source.
Below ...
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75 views
Which differential protocol to use when redriving Ethernet?
I want to redrive a 100-BaseTX signal on a board. The signal is to be redriven 3 times (by the same setup). On one end is a STM32 NUCLEO-F767ZI board, and on the other end is a GbE switch including ...
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2answers
39 views
Input common mode voltage of AC coupled differential pair
I was reading OnSemi's AN8173 app note and couldn't understand why input common mode voltage of AC coupled line is equal to VTERM.
My thought was each input of the receiver, D and \D, will swing ...
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1answer
39 views
Differential equation of the NPN transistor configured as a voltage divider
The mathematical model in AC of the NPN transistor is represented by the pi model which is only one resistance in parallel to the resistors of the divider and the DC source in parallel to the ...
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0answers
45 views
Current transformers, voltage output vs current output
I'm designing a energy monitoring system that is using split-core clamp current sensors to measure multiple high power lines(40+ lines at 300A each) in a MCB room of a building. I'm currently sourcing ...
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39 views
How can FPGA differential signal use lower power when it has two lines instead of one?
I am a bit confused about differential signaling on FPGAs. I am trying to figure out how does power dissipation in FPGA differential signaling compare with power dissipation in FPGA single ended ...
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1answer
87 views
What “mode” is static electricity (lightning?) Is it common-mode, differential-mode? It seems half-way, or “mono”
The common-mode or differential-mode designations assume two conductors, one in-phase, the other anti-phase, but a static circuit is different because the "conductor" is concentrated in thin ...
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27 views
How do you find rO when solving this differential amplifier?
gm could be determined using Jacoletto (40*Ic, where Ic was found while solving the bias point)?
Some of my attempts at solving the circuit
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32 views
FT232RQ USB pins order confusion [duplicate]
I am implementing a USB to UART conversion board with a FT232RQ. What confuses me is the fact that the USB_D+ and USB_D- pins of the package are sequenced in precisely the opposite order as they are ...
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127 views
Upper 3-dB frequency of differential amplifier with current mirror load vs with resistive load
In the BJT case, why is it that the upper 3-dB frequency of a differential amplifier with a current-mirror load (1st picture) is lower than that of a differential amplifier with a purely resistive ...
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40 views
Measure Battery voltage with ADC in noisy environment and supply circuit from that same battery. single ended/differential mode?
need your opinion:
Want to build a device that is able to measure a battery voltage and send results wirelessly every x minutes.
The Battery has nominal 24 volts. Batteries are in a yacht (e.g. engine ...
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2answers
58 views
differential instrumentation amplifier in LTspice not working
I was trying to simulate an instrumentaion amplifier in ltspice.
the problem i am having is the output when measured across C1 is wrong. since i have an amplification factor of 11, i was expecting to ...
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1answer
53 views
No gain in CMOS differential amplifier
Currently I'm working on the design of 1st stage of CMOS differential amp (pic. 1). I'm using classical design to achieve at least some gain. I'm using CMOS 90nm process and SPECTRE simulator.
So far ...
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1answer
55 views
Simulating PMOS differential amplifier in Cadence
I am studying about rail-to-rail opamp design and I am trying to recreate the Itail vs Vgs (in this case input common voltage) curve from the link bellow (pages 5 and 6):
https://mixsignal.files....
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29 views
Improve range on a differential ADC
I'm using an MCP3425 ADC, it has differential inputs but I'm using it as single ended mode.
The signal that I want to digitize comes from an integrator circuit (an op amp with a capacitor in its ...
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1answer
30 views
Attenuation in the circuitry of differential vs isolated probes
Using this website as a reference for differential probes:
https://circuitcellar.com/research-design-hub/high-voltage-differential-probe/
By Andrew Levido, Circuit Cellar
The differential probe is ...
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0answers
39 views
Differential communication, VCC and GND recovery
modern MCUs are consuming so little power that I started thinking about using only two differential data transmission lines for sending not only data but power also. I made a simple schematic below of ...
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1answer
39 views
What could be causing differential signal drift?
I looking at a differential signal on a scope, and I see that while the signal should be exactly equal and opposite the values are slowly drifting slightly.
The quantity I'm looking at is the areas of ...
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1answer
68 views
I2C differential network architecture using PCA9615
I'm building an architecture for a large scale robot (3x3meters) and I would like to build a specific architecture around I2C differential to control motors drivers (this should be noisy).
My problem ...
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1answer
66 views
Measuring voltage without a common ground
When measuring a power source voltage using a differential amplifier, without a common ground with amplifier supply, to which ground should we connect the differential amplifier resistor ground? V1 ...
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1answer
34 views
Maximising sensitivity of AC voltage measurement on top of DC voltage with Arduino ADC
I have:
Single supply rail voltage (3.3)
current sensing transformer that outputs an 1v pk-pk value at is max rated sensing current (10A). The Transformer biased at 1v DC in order to ensure that the ...
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2answers
79 views
Read USB data to arduino [closed]
If I take a USB cable connect it with my cellphone from 1 half and in the other end I connect VCC and GND to VCC and GND pins of the arduino and the D+ and D- pins to digital pins and use a ...
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1answer
35 views
Differential signalling with negative feedback
Does differential signalling always comes hand to hand with a negative feedback circuit?Else the 1s and 0s would be the same!because if we have ground in the inverting pin then the output voltage will ...
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2answers
84 views
Is a fully differential opamp subtractor possible?
I know how to subtract two single-ended voltages with an opamp configured as a subtractor.
I'm learning about fully differential signal processing and I'm wondering if it is possible to subtract two ...
