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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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
44 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
100 views
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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49 views
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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32 views
Differential amplifier CMMR, NON-IDEAL Op-Amp used
I have a little trouble with the analysis of a differential amplifier.
What I want to do is to determine the CMRR of the whole amplifier taking into consideration the CMRR of the op amp.
This is the ...
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1answer
51 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
54 views
Detect if a CAN node is Transmitting or Receiving [closed]
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 it's ground/low reference.(high ...
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34 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
38 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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29 views
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
57 views
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
51 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 ...
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1answer
39 views
Common Mode Noise on Differential Lines Driven Against Chassis GND
How is common mode noise filtered on differential lines that have a noise source that is driving them relative to chassis GND? I drew a picture of what I am imagining below. Imagine a PCB with ...
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2answers
74 views
How to analysis this Operational-Amplifier circuit?
This is a reference buffer circuit that make a single-end audio input to be the differential inputs for ADC.
Circuit-1:
It does not like typical Op-Amp circuit of the same purpose like below.
...
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2answers
37 views
Increasing drain current, decreases common-mode level
The basic idea behind the CMFB setup is that increased output common-mode level feeds back into the gate-source of the triode devices and causes drain current to increase and hence output CM level to ...
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1answer
33 views
Impedance matching of USB device WITHOUT cable
If I understood correctly, when designing PCB with USB, the 90-ohm differential pair of D+/D- trace if for matching the USB cable differential impedance. Otherwise, there will be a signal reflection ...
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1answer
50 views
Gilbert Cell Output Current
I do not understand the basic of a Gilbert cell.
I see that as its output we consider the output differential current Io. But I do not understand it. Is the load connected between the points 1 an 2? ...
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1answer
40 views
How to find the Common Mode Rejection Ratio of this circuit?
My attempt was like,
by using the formula,
I can get, \$CMMR=\frac{\sqrt{2\cdot4\cdot8\cdot5\cdot10^{-6}}\cdot44000\cdot2}{x}\$
For the denominator, I used both 10% and 20%, but all the finals were ...
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1answer
48 views
differential measurement vs ground
I am looking to measure an incoming V vs ground with an ADC (MCP3424 or equal). The Vin vs Gnd can be anywhere from -1.5V to +2.0VDC. I looked at using an op amp with level shift, when I came across ...
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1answer
62 views
How to write inductor ODE equation properly?
I've drawn a following scheme, and now want to write ODE system for describing inner processes, in order to explore it:
simulate this circuit – Schematic created using CircuitLab
I wrote the ...
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1answer
64 views
Differential pairs; length matching between pairs
I'm currently busy routing a high speed design containing MIPI signals @ 2,5Gbit / lane to a connector on an 8 layer board. As MIPI also contains a clock pair, it is advisable to match the length ...
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2answers
257 views
Voltage output waveform of a differentiating amplifier
I have the following picture of the input and output voltage waveforms from a differentiating amplifier as shown below:
And the schematic is as shown below:
My teacher claimed that these waveforms ...
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2answers
84 views
differential grounded coplanar waveguide, GND-sig-sig-AVDD instead of GND-sig-sig-GND
I know we can route microstrips on top of both ground and power planes, but can we use Grounded coplanar in this arrangement?
bottom is GND
In top layer we have one GND and a PWR.
All gaps are 0.15mm
...
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0answers
44 views
Bonding DC Minus to Ground with Resistor for Remote Power?
Layout:
I have a system that has 3 serial networks that run a variable length with one central processor talking to multiple endpoints via Modbus RTU, Canbus, and another rs485 that talks a protocol ...
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48 views
Calculating current and voltage from RL circuit through differential equation
Our circuit, where R1 = 3 Ohms, R2 = 1 Ohm, R3 = 2 Ohms, L = 5 milliHenry, and I = 0.01 Ampere.
Trying to figure out the differential equation for this circuit, as well as the current for the ...
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1answer
48 views
Is difference amplifier a differential amplifier with a voltage gain of one?
I see these two terms are used in same context.
But what is the difference in meaning?
Is difference amplifier a subset of differential ampfier with unity gain? I couldnt find a duplicate question.
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3answers
93 views
Bipolar signal used in differential ADC
I'm trying to find a way to convert a bipolar signal from a load cell (Futek) to an input for a differential ADC on a TIVA microcontroller(TI TM4C123GH6PM). The load cell's amplifier outputs a bipolar ...
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1answer
28 views
What causes the necessity for a bias resistor for floating differential mode inputs?
Following excerpt from a text says Figure a and Figure b are equivalent:
But in practice when Figure b is used we are recommended to use a 10k or upto 100k resistor between the inverting terminal and ...
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2answers
55 views
Noise mitigation in +/-5mV instrumentation amplifier?
I am building a differential amplifier to boost a 0-5mV (delta) signal off a load cell wheatstone bridge.
In simulation, the design works here (falstad):
(for those who have not used falstad circuit ...
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29 views
Line driver circuit with with MC3487 not clear
I am looking at an old Heindenhain LS623 optical slide with with a LM339N comparator and an MC3487p line driver. This slide is about 20 or more old and can not be repaired anymore by Heidenhain. I ...
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2answers
61 views
How to connect/terminate differential CML logic outputs to single ended ECL logic input?
If I want to use a CML differential gate's (Ex: SY58051AU) output as the enable ECL input for an ECL counter(EX: MC100EP016A), whats the best way to connect the output to input? I think I need to use ...
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2answers
41 views
Finding Vout and Gain of a differential amplifier
I am given this figure below:
And I am trying to find Vout and the gain.
From looking at this source: https://www.electronics-tutorials.ws/opamp/opamp_5.html I have determined the gain to be 10k/1k ...
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1answer
45 views
Differential (Subtractor) op amp with low pass filter
is it possible to have a subtractor circuit with a low pass filter in it?
My thought is that I would have the possibility of doing that if I add a capacitor in parallel with R3. Is it actually ...
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2answers
64 views
Can CML differential signal lines be flipped to act as a NOT gate?
If I want to invert a CML differential D-Flip Flop (Ex: hmc747lc3c) output before entering into a CML Counter(Ex: MC10EP016), is it as simple as flipping the signal lines before entering the counter? ...
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17 views
Single Ended DAC to Differential Input Modulator
I'm trying to drive a differential input IQ modulator (LT5571) with a single ended DAC (MCP4912) for modulation of a narrow band signal (~10kHz max).
Because of the nature of the low frequency ...
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1answer
47 views
HFA3096 transistor array breakdown voltage
In the book Learning the Art of Electronics, one of the labs is to build a differential amplifier with a CA3096 transistor array. The author admits that the chip may be difficult to find and gives the ...
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1answer
86 views
BJT differential amplifier: What causes common mode voltage gain?
In any normal op amp, if it was ideal it would have a gain such that the output voltage would be
However in reality this is not the case as there is a common mode voltage gain and hence in reality ...
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82 views
PCB HDMI high speed routing suggestions on my layout
I would like to get suggestions from all the high speed PCB layout experts on my PCB design.
I have a board with HDMI transmitter IC whose output is going to HDMI switch IC. The switch IC also has ...
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1answer
31 views
Discrepancy in datasheet for AM26LV31E?
The AM26LV31E datasheet, a differential line driver, states this (on page 4):
and this (on page 10):
At best, this seems ambiguous and, at worst, contradictory. Is the logic of this statement (8.1) ...
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1answer
56 views
Tail resistor in differential gain
Why doesn't the tail resistor feature in the denominator for differential gain (whereas it does for common mode gain) in the differential amplifier below? (Fig 5N.28 from Learning the Art of ...
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1answer
80 views
Ideal Op Amp Circuit
I have a question about the circuit below. I want to find Vo in terms of Vi. But I don't fully understand the principles about an ideal op amp's output. You will see my questions in bold at the bottom ...
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2answers
63 views
Differential amplifier with feedback resistor
In this circuit, if a resistor of 1 M\$\Omega\$ is connected between A and B, what is the effect on the stability of the quiescent point?
The analysis I made led me to believe it would provide ...
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87 views
Differential Amplifier with TLC272 vs TL082
I have an LM2576-adj configured to step down 12V regulated output from a wall wart to around 5V-ish (see schematic). On the 5V output I have a 0.1 ohm sensing resistor (Rsc) to measure the output ...
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0answers
52 views
How to connect a MEMS Microphone Breakout - INMP401 to a RN-52 bluetooth module?
I intended to use a INMP401 (MEMS MIC) to capture audio and stream it via bluetooth using an RN-52 bluetooth module (RN-52). The RN-52 has inputs for differential +- signals.
The INMP outputs ...
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2answers
138 views
Using a fully differential amplifier as a differential ADC driver
Regarding my previous question, I decided to use a “fully differential amplifier” to obtain a voltage gain of 10. The source and ADC are also differential. The source is unipolar and its output ...
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2answers
72 views
Series RL current equation
I am trying to derive a inductor current equation for \$i(t)\$ in a series RL circuit when the switch is closed at \$t=0\$, as seen below:
I have posted my attempt so far but I'm having trouble ...
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41 views
Logic Style Level Vs Hardware Level
In the book: Advanced DPA Theory and Practice: Towards the Security Limits of Secure Embedded Circuits 1, it is explained that the countermeasures against Side-channel Cryptanalysis could be ensured ...
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2answers
131 views
Ground, common, and Earth ground confusion
I am learning on transmitters and input modules nowadays. But the usage of word 'ground' is confusing me. What does 'ground' mean there (earth or power supply common)?
If it is earth ground, why we ...
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51 views
Series RL Circuit Transient Analysis
I have worked through a question and I am unsure if my answer is correct. It is a series RL circuit with a switch that closes at t=0, supplied by a dc source, which I am trying to derive an expression ...
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2answers
44 views
How can I allow a smaller clearance value for differential pairs in Altium?
I have finished routing a PCB in Altium (v17) and am resolving design rules violations.
In short, everything checks out except differential pairs that are violating the ...
