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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Differential filters: high pass, low pass, band pass
I am looking to use a band pass filter in an EMG circuit design using the differential signals you receive from an op amp (differential/instrumentation). I have been looking for what is the proper way ...
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How to obtain a high precision mV signal within a specific interval using a variable resistor?
I want to design a circuit which outputs a signal ranging from 0-70 mV using a variable resistor ranging from 80.51 Ohm - 183.05 Ohm and a supply voltage of 12 V. My idea so far has been to make a ...
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1answer
34 views
Differential to single ended digital signal
i have a 8GHz differential clock to convert to single ended. Is taking one end of the clock enough? what are the risks of doing so?
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Differential low pass filter to single ended -> Differential low pass filter
I'm designing an audio DAC based on the PCM1690 from TI. Datasheet
One requirement of the DAC is differential outputs. Since the PCM1690 has differential outputs, this is not a problem. However, the ...
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49 views
Single-ended analog signal to differential
I need to transmit 2 analog signals over a cable in a noisy environment.
How to transmit them as differential ?
Given that :
Each signal can be used to inject and receive current (< 130 kHz, &...
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EAGLE. Differential pair routing. Width of the track changes after first change of direction
I try to route differential pair of tracks. When I click the mouse to change the direction it also changes the width
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1answer
107 views
How to transmit analog signals over cable?
In my current project, I need to transmit 4 analog signals (A1, A2, A3 and A4) on a cable from one PCB to another. I am working at 3 VDC and the distance between them is relatively short (< 30 cm).
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1answer
116 views
RS485 Eye diagram - does it look good?
I got a new diff probe, I am trying it out on RS485. I'm triggering on the rising edge. The RS485 is running at 25Mhz.
Does the eye diagram look good?
Could I double the speed (50MHz) and be ok? (...
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39 views
Quadrax routing on a PCB
When connecting twisted pair wires to a printed circuit board, I hope I am right in thinking that differential pair routing is used on the board in either a stripline or a microstrip configuration to ...
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Capacitor across Vlo and Vhi on DAQ, switching power supply
I have a switching power supply (RC Esc). I am measuring the input voltage from battery using a voltage divider. The Divider is attached to a differential DAQ. I have very large transient spikes ...
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52 views
Why does Altium say this net is uncoupled?
I have some differential pairs in Alitum. They require impedance matching to 100R, which is easy enough. Putting the numbers into Saturn PCB Toolkit V7.08, it works out that I want a conductor width ...
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1answer
68 views
PCB Routing of CANH and CANL
Continuation from an earlier question: Current Consumption of CANbus (CANH and CANL)
I understand how to specify my power supply for multiple CAN transceivers but I am now wondering about the details ...
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55 views
Current Consumption of CANbus (CANH and CANL)
I'm looking to use the SN65HVD230 CAN transceiver but had a question about the current consumption.
Datasheet: http://www.ti.com/lit/ds/symlink/sn65hvd230.pdf
In table 8.3 Recommended Operating ...
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1answer
59 views
Questions about CAN
I'm trying to build a network of interactive LED matrices which will communicate to each other. Each node will be a circular PCB containing an 8x8 RGB LED matrix that is connected through a vertical ...
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1answer
47 views
Does input impedance of an isolation amplifier or a transformer have impact on common mode to differential mode conversion?
I have a question where I can only explain it clearly by an example. It is about conversion of common-mode interference to differential mode due to overall system imbalance.
I will use below two ...
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Question about a common mode feedback circuit
I'm studying fully differential op-amps. I know from the theory that with fully differential op-amps, unlike the single-ended op-amp, the output common mode is not stable because of unavoidable ...
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2answers
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differential opamp reference
simple model of a diff opamp with an independent differential signal source
figure 1
how does current flow through the transistors since V1 and V2 and referenced to each other and not to vee? i ...
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1answer
38 views
Requirements for measuring PCIe 2.5GT eye diagram
What is suitable equipment for measuring an eye diagram of PCIe differential pairs. I would like to evaluate the signal integrity of a PCI lane RX/TX/CLK 2.5GT. What is the recommended minimum ...
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Consequences of leaving unused inputs of clock buffer floating. Alternative: best practice
I'm using a Si53342-B-GM
Original datasheet download at silabs for the si5334x-series
as a clock buffer.
In some cases I only need to distribute a single clock signal and in some of my cases I ...
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1answer
45 views
Differential equation for a notch filter RLC circuit
I'm trying to write and solve a differential equation for this simple RLC notch filter and I'm not sure what I'm doing wrong.
simulate this circuit – Schematic created using CircuitLab
So ...
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2answers
48 views
Measuring voltages from different sources sharing Common ground that might differ slightly
I have a design with resistor dividers and low pass RC filters dropping down 0-32V to ADC range of 0-1.8V. With multiple channels, I attempt to measure voltages from different voltage sources on a ...
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1answer
45 views
Multi-stage fully differential bandpass filters
I've recently been doing a bunch of research on analog filtering in preparation for a data acquisition system I'm building. For context, while I'm fairly comfortable with FPGAs and digital/computer ...
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10/100Base-TX Ethernet differential pair routing on a 2 layer PCB
My project involves the ESP32 and Ethernet. To get basic functinallity I intend to use the LAN8720 PHY because it is supported by ESP-IDF out of the box. But I also want to try out the KSZ8863RLL 3-...
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2answers
60 views
MAX999 draws current through negative input
I have two versions of the input signal:
5V inactive level, 3.2V active;
5V inactive level, 0V active level.
Thinking on making universal circuit to support both signals, I decided to use comparator,...
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1answer
60 views
USB bus Differential signals and Pin swapping
USB 1.0 and 2.0 has D+ and D- two differential pins.
My understanding is that differential signals are symmetrical so any of the two lines carries an inverted signal of the other line.
But in the ...
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47 views
About the differential gain [duplicate]
Let's consider any circuit which contains a differential pair, for example a telescopic cascode single stage OTA:
In every circuit like this one, my professor and every book compute the small signal ...
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2answers
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Question about differential signals and feedback
Let's consider, for example, this circuit:
During lessons, our professor always assumed perfect differential input (two signals with the same dc value and with equal and opposite amplitudes). As a ...
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1answer
46 views
Bandwidth of an oscilloscope with differential probe
I am planning to buy Rigol MSO5204 scope with a bandwidth of 200 MHz. I need to measure the timing difference between 2 (or more) signals of up to +/- 7 ns. Since this scope has 8 GS/s ...
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How to do Transient analysis?
Consider the above example earlier I used to form a differential equation and then do its solution using Laplace,but for this example the differential equation comes out to be non-ordinary.
Please ...
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4answers
235 views
Question about differential signals as input of an operational amplifier
I'm studying the circuits which are used to implement operational amplifiers. For example, I've studied the two stages amplifier (in which the first stage is a differential amplifier with differential ...
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1answer
57 views
Differential pairs or single ended signals for 1m cable
I have one control board and 3 additional boards for the power electronics, that send and receive data from the control board over a distance of ~1m (3ft). All signals are single ended.
I have to ...
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1answer
208 views
What are these wiggly USB 3 traces on my motherboard?
I was taking a look at my motherboard, and I noticed the above traces on the USB 3.0 ports. A bit of prior research:
The C34WH IC is probably a SN74LVC2G34 Dual Buffer Gate.
Unclear what chip the top ...
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4answers
159 views
Where does return current flow for a differential signal?
As far as I understand, return current flows the "negative" channel for a differential signal connection. Only if it is not balanced well, there might be unwanted return current in reference GND or ...
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calculate the ouptut of two operational amplifiers in a series
i want to calculate Vs which is the output of this circuit
simulate this circuit – Schematic created using CircuitLab
so i just want to equation that can help me find Vs.
please help me, ...
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Current mirror loaded differential amplifier with gate of current source as output
I'm trying to calculate the gain of this current mirror loaded differential to single-ended amplifier with output on the other side as opposed to the usual configuration. My result is 1/2 gm_N1(ro_N1||...
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3answers
107 views
Is the impedance control of differential pair traces a transmission line problem?
I read in an article of design reference that "If the length of the interconnect PCB is greater than 1/10 th of the wavelength, we should consider using the transmission line instead of ordinary ...
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2answers
68 views
differential amplifier gain
i know that the differential gain of the differential amplifier ( mosfet or bjt ) is _gmRc or _gm Rd
looking at the curve : if the current went down in one side and up in one side the gm will change ...
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1answer
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How can i get the Q operating point of the differential amplifier?
I'm working with this type of configuration: Differential amplifier, and I need to find the current for this circuit so I can have maximum symetrical swing, and for that, I need to find the operating ...
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Designing a two stage differential amplifier with MOSFETS
As a part of a "Test you understanding quiz" i had yesterday at school were we tested our understanding of differential amplifiers and mosfets i came across a question that asked us to design a ...
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2answers
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Transitioning between 90 and 100 ohm diff pairs using coupling caps?
I'm building a PCB carrier for an FPGA SoM. The SoM has 100 ohm diff pairs routed for all the high speed IO. I'm implementing USB 3 on the carrier so should be routing 90 ohm diff pairs. What is the ...
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1answer
63 views
input resistance of differential amplifier
i have a question about the differential amplifier
i know that the input resistance for the common mode is
Rin = rpi + 2 Beta Ree / 2
but my question is what is the input resistance for the ...
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2answers
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Question about differential amplifier
why is there 0.7V instead of 1.2V on the common emitter?
if you go through Q1 mesh : Ve = 0.5+Vbe = 1.2 instead of Ve = 0+Vbe = 0.7 from Q2.
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0answers
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Differentiator circuit sees noise on PCB after 2 min
I'm new to PCB design, and looking for some advice. I designed a PCB shield and I'm seeing a lot of noise in my differentiator circuit. The circuit will run perfectly for about 2 min and then all of ...
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1answer
119 views
Should Ethernet MDI Pairs all be Length Matched (Inter-Pair) before going into magnetics?
I've been trying to find information for the above question and I can't seem to find anything. I have 1000 BASE-T lines coming from an Ethernet cable to a PCB mounted connector. I'm pretty much ...
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2answers
126 views
Detect if a CAN node is transmitting or receiving
I am not an electrical engineer or EE student; I'm a diagnostic technician. AFAIK, a CAN transceiver receives bits by measuring voltage between the network and its ground/low reference (high ...
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0answers
38 views
Singled ended or Differential - Engine Control Unit
I know this topic has been beaten to death but I still have not got a clear understanding. Pardon me for my bad explanation as I am an automotive engineer by trade.
I am simulating an engine knock ...
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1answer
41 views
How critical is it for SN65HVD1780DR A/B Differential signal lines to have matched trace length?
How critical is it for the A/B differential signal lines of SN65HVD1780DR to have matched trace lengths on PCB?
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Current source for discrete differential amplifier
I hope someone can point me to the right direction. Basically I face the same problem like the author of the following question. How do I choose the correct current for my differential amplifier? I ...
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2answers
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Does it matter if differential pairs have no reference plane or cross reference planes?
More specifically, does it matter on a PCB if routing differential pairs if they cross reference planes?
Do they need a reference plane?
Is there even a reference plane with a differential pair?
I ...
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2answers
60 views
Oscillations on High Side Sensing Current Source
I designed a simple adjustable constant current source that uses high side sensing but I can't seem to figure out where the oscillations on my output are coming from. The circuit is shown in a picture ...
