# 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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### How can I improve this Ethernet differential pair?

This is my first 100 Mbit/s Ethernet project (I am doing it to learn more about differential signals). I did two things that I don't know if are good or bad in this particular case. One is to route ...
39 views

### Multiple differential tranceivers on single bus

Im using a few moduls of rs422 tranceivers connected on single bus Easy module has transciver with TX input, RX output power end differential pair output and input - but no EN pin to hold the ...
96 views

### Solving a simple single-ended differential amplifier

simulate this circuit – Schematic created using CircuitLab N.B. I_D=KVov^2 without the 2 I’m really confused with this excercise, my problem is to calculate the A_v=v_out/vd and the cutting ...
39 views

### signal types and wire types

I am trying to understand the selection criterion for choosing between a signal types and wire type out of the following: Signal types: Gnd reference uni-polar signal Gnd reference bi-polar signal ...
30 views

### What could be the reason if the AC coupling option goes away when I attach a differential probe (P6248) to a Tek MSO5204 scope?

When the scope is not attached, I could see both AC coupling and DC coupling options for the channel settings. The moment I attach the differential probe, the AC coupling option goes away. Any reason?...
111 views

### Converting differential-current output to single-ended voltage; adjustable gain

I want to convert differential-current output of DAC2902 to single-ended voltage. Can I do it with following differential op-amp configuration at the output of the DAC? The voltage gain is fixed = 1 ...
43 views

### Is this slide wrong about the differential signal waveform?

While learning about the differential signals I saw this youtube video. It looks like this slide does not correctly shows the voltage levels of the complementary differential signals, as I have marked ...
471 views

### How to do low pass filtering on a differential signal

If I have a differential signal on a pair of wires then how would I do a simple RC low pass filter on this differential signal?
62 views

### What to do with GND of differential mode signals?

Let us say I have 2 modules. First module gives a differential signal output on a pair of wires while the second module takes the differential signal input. When I connect the differential signal ...
124 views

### Open-loop frequency response for an op-amp

I want to know what is the ideal circuit to measure open-loop frequency response and why?I have seen the typical open-loop frequency response curve for an op-amp a lot of times. But when I try to plot ...
81 views

### Use of twisted pairs with fundamentally single-ended DUT

Let's suppose I'm interested in measuring the voltage response of a DUT to some imposed voltages. The DUT takes V1, V2, V3 as inputs relative to some GND, and outputs V4 relative to the same GND. All ...
133 views

### Is it possible to route USB 2.0 using regular traces?

In the future I will be faced to design a system that includes USB 2.0 connectivity. I've seen that there are many trace calculators, but as far as I can see, they refer to microstrip lines. So, is it ...
230 views

### Degenerated Differential Pair voltage headroom

I was reading about ways to make the differential gain linear by adding degenerative resistors Rs as shown, but it has voltage swing limitations, having swing reduced by Is*Rs( when one of the MOS ...
117 views

### Wiring a BJT differential amplifier in a circuit

I need to switch a 12V relay when an input signal passes a certain voltage threshold. I use this popular BJT amplifier: In my case: VCC = 5V ...
56 views

### Is this signal reflection or a damaged transmitter?

This is (an isolated, differential) capture, 1µs/div, of some Profibus communication over about 10m of cable. The first image is typical for about 90% of packets and seem fine. Most are +/-5v with ...
186 views

### LM324 output voltage gets low in difference amplifier configuration when UPS supply is turned on

I am using lm324 as difference amplifier to measure the string voltages of lithium ion battery pack ( four cells in series). I am using all single package of LM324 that have 4 Op-amp. The Lithium ion ...
81 views

### Texas Instruments fully differential op amp app note: I'm having difficulty understanding an equation (single ended to differential video conversion)

I am developing a circuit to convert single-ended video to differential, based around the TI article "Converting single-ended video to differential video in single-supply systems" by Jim ...
38 views

### Long tailed pair not working to compare signals from 2 LDRs

I've been trying to compare my signals from 2 LDRs to feed into Arduino's ADC. However I can not get any gain from my differential amplification. The problem comes when I have high resistance from 1 ...
161 views

### CAN Split Termination Capacitor Calculation

I'm trying to use the split termination on a CAN bus, but I'm a bit confused about the calculation for the split termination capacitor. It is described in Figure 10 in the Texas Instruments app note ...
30 views

### ADC negative input clipping vs scaling and bias

So, I have this differential ADC (AD7641) and plan to use AD8139 as his driver. The goal is to digitize a signal (a sine wave) of about 3.5Vpp and 36KHz. The signal is actually single-ended and ...
64 views

### Long tailed pair

How do I adapt the long tailed pair to fit my requirements? I've seen circuits where they use 9V Vcc with 10k resistors. From my understanding the resistors are there to prevent floating base from ...
96 views

### Difference between two gain +1 op-amp topologies

I've got two differential driver circuit designs that take a single ended input and provide as output a buffered pair of +1 and -1 times the input and I'm struggling to understand the difference ...
69 views

### How to take my differential filter and design it for a different frequency and impedance?

I have a board with this differential PI filter: simulate this circuit – Schematic created using CircuitLab Say it's designed to pass signals with frequency X and bandwidth B1, and now I want ...
226 views

### Differential amplifier input voltage higher than the supply voltage

I want to measure current at high side of circuit but input voltage is higher than the op amp supply, is it ok to do the input voltage division like schematic below?
21 views

### “Coupling” gain-setting resistors in a single-ended source, differential amplifier?

I am working on a fully differential amplifier design that receives a single-ended differential voltage from a piezo sensor. I computed a theoretical gain and selected appropriate resistors and it ...
290 views

### How do industrial PSUs switch to 4-wire measurement?

Almost all high end PSUs provide a 4-wire voltage measurement at the load, How do they switch to 4-wire measurement? Is it in software, reading another ADC channel or they use a relay? Can it be done ...
39 views

### Can a differential probe and regular coax wire be connected safely to only one channel of scope using a tee connector?

I would like to ask if I can connect a differential probe and a coax wire through a tee connector to 1 channel of an oscilloscope, in order to take different DC measurements. The connection topology ...
31 views

### Flipped length and Z-matched lines. How to pcb patch?

I think the title says it all. I accidentally flipped the P and N lines downstream of a CSI/MIPI retimer (they are impedance and length matched). Is there any way at all to patch this on the pcb?
78 views

### Solve differential equation for R-L circuit

Given that Ri+Ldi/dt=Vsin(wt). The answer given here is i= (V/Z)[sin(wt- Φ) + ke^(-t/τ)]. I could not solve this equation further.
124 views

### Confusion on operation of bipolar differential amp (long tailed pair)

Let's say there's a basic differential amp constructed with two npn BJTs. And a current source is working as the tail. The task I have is to amplify a small AC signal of around 1mV p-p, referenced to ...
2k views

### Solar tracker using photodiode: circuit design [closed]

My aim is to differentiate between two different levels of illuminance. I would like to know when one photodiode is in shadow and other in direct sunlight. So I don't really need the level of lux but ...
41 views

### Single ended biopotential amplifier

I have to design a single ended biopotential amplifier circuit based on an already existing model for differential amplifier. In other words, I have a circuit in which each channel has two inputs from ...
153 views

### op amps comparator or differential amplifier

I have a part of electronic schematic as described bellow, I'm a little bit confusing about the function of the LM321 amplifier. In this case, can we say that is a differential amplifier or just a ...
155 views

### Differential amplifier common mode and differential mode gain

I need some assistance on the derivation of the formula for AV(cm) depicted in the figure below. the +/-2 delta_R/R and +/-4 delta_R/R are giving me hard time deriving. The book probably provided ...
20 views

### Difference Amplifier to retrieve sine wave

I have built the following summing amplifier circuit from a Fourier approximation of x(t)= 0.143 + 4/π ∑((sin⁡(2π(2k-1)ft)/(2k-1)). I am now trying to retrieve a sine wave from the output of the ...
97 views

### BALUN vs other methods

I have a differential analog signal traveling over 2 coaxial wires. I need to convert to single ended. When should I use a BALUN ? When are other solutions such as OPAMPS more appropriate ?
141 views

### BJT differential amplifier

Is there any reason why the gain of a single ended input BJT differential amplifier, with one Rc, is a good approximation of the value of Adm for a common mode input. The simulation shows the ...
132 views

### MAX487 can transmit but won't receive

I am trying to use a MAX487 chip to convert a regular UART signal to half-duplex RS485 signal and vice versa. I am using Atmega328PB as my micro controller. My circuit has no problem with transmission,...
103 views

### Is this differential pair routing OK?

I am working on a PCB layout on a very space constrained, 4-layer board. On the board is a MIPI-output image sensor (1 lane) which go to an FPGA. Layer 1: Image sensor Layer 2: Full Gnd plane Layer 3:...
69 views

### Differentiator Op-amp with a triangular wave

I’m trying to create a differentiator op-amp. The input signal is a triangular wave of frequency 100Hz and amplitude 1V. The circuit I have designed features a series resistor (Rin) and capacitor. ...
49 views

### Analog differential signaling

I'm a software engineer that sometimes has to deal with some electronics. So I'm by no means an expert... I want to control a BLDC motor and I have added a thermistor to the windings of the motor so ...
113 views

### Routing 5 differential pairs over a short distance with limited space

I have 5 differential pairs (4-lane MIPI-DSI) going from left (SOM header) to right (FPC connector). As you can see on the right, for each lane, the signals end on opposite ends of the FPC connector. ...
48 views

### Issue with dividing the voltage and feeding it to an differential amplifier

I have a ladder voltage divider which divides 70v into 7 different steps (10V each). Output of this voltages is fed to a unity gain differential amplifier to get the difference voltage (70 - 60 = 10)....
24 views

### Battery powered device - How to measure external floating differential voltage

I have the following task. As depicted in the sketch, I have a battery powered device which needs to measure the differential voltage VIN between two external nodes, EXT_NODE1 and EXT_NODE2. It is not ...
20 views

### Switched-cap/charge pump only way to generate negative rail voltage for op-amp?

I need to design a daughterboard that gets mounted directly to a piezo mic to condition the signal before transmission. Part of the conditioning is a full wave rectification. Thus, as you'd expect ...
98 views

### Differential amplifier (transistors): Which input is inverting?

For example, on the following differential amplifier it is clear, which of the inputs is the inverting one. If the voltage on the non-inverting input (base of Q1) is higher, the current through Q1 ...
127 views

### Why do we need differential amplifier after Transimpedance amplifier?

I am implementing the circuit published in AN3025 Transimpedance Amplifier Design as shown below. When I am simulating this circuit, a few questions come to mind: Q1. Why do we need a differential ...
36 views

### Decrease voltage at input

Why connecting this sensor output to pin 22b, the voltage at this point become half? For example, if we disconnect this sensor from the circuit board, the voltage at this point is about 6volt but when ...
547 views

### Differential to single-ended converter

Originally I wanted to setup a simple curve trace circuit to measure the characteristics of a BJT I salvaged. This circuit operates by measuring the voltage and current through the transistor for ...
98 views

### Two Amplifier problem 1

The two questions I am confused about are: (a)Determine the value of REE to give emitter currents IE of 350 μA in each transistor and the smallest value of RC to enable a 1 volt peak-peak maximum ...