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-
754
questions
0
votes
1answer
25 views
Laplace transform rotational mechanical system
I have a system with an input torque Te and output angular velocities w1 and w2. I have defined the outputs relative to the system however cannot seem to work out how to find GM(s). omega2 is the ...
0
votes
0answers
23 views
Why does the output of the mosfet differential pair connect to the gate of the pmos of a common source amplifier?
I'm told that a simple operational amplifier made from MOSFETs can be shown in the picture below.
M1 M2 M6 and M7 make a differential amplifier. M3 is used as the reference mosfet to create a current ...
1
vote
0answers
51 views
Ultrasound piezo crystal and doppler for blood flow velocity
I am currently working on a microcontroller based project to measure the blood flow velocity using ultrasound doppler.
I have purchased two Spengler 8 MHz continuous mode probes in order to measure ...
1
vote
1answer
36 views
How do cheap Raspberry CSI-2 cables get around differential impedance matching
I am trying to design a circuit on (double sided) flex PCB that happens to have CSI-2 signals on it.
I would like to find out what is wrong with my deductions presented below, or what part of ...
2
votes
3answers
53 views
LVDS/differential driver source impedance matching
A very basic/stupid question.. I'm designing some LVDS multipoint pcbs, and I'm a bit confused about the source termination on the driver end. my colleague said that ideally there should be a 100ohm ...
0
votes
1answer
61 views
Why is input resistance parallel with the base of BJT?
I'm solving for the third stage. The resistance looking into the base of Q7 is taken between its base terminal and ground as follows during small signal analysis for single end gain of Second Stage ...
1
vote
1answer
74 views
Can USB 3.0 tracks be closer together than 5W if they're quite short?
I am currently laying out a space constrained PCB which contains some USB 3.0 Superspeed differential pairs. These USB signals are confined to the PCB, going from a Cypress CX3 chip to a USB 3.0 Hub ...
6
votes
2answers
595 views
Amplify difference between two photodiodes
I have two adjacent photodiodes in photovoltaic mode, with two transimpedance amplifiers. Unfortunately, my MCU (nRF52840) is one meter away, and I expect a fair amount of noise to enter the system. ...
0
votes
1answer
23 views
MCP2551 sending with 4V differential voltage
I'm working on a CAN Bus Module with ATMEGA328P, MCP2515 and MCP2551. In my test setup, I have the module connected to a Raspberry Pi with a CAN hat.
The communication works in general - both nodes ...
0
votes
0answers
24 views
USB differential data lines pulled up to 5 V
My design uses the compute module 3+ board from the raspberry pi foundation. I used the FSUSB42MUX schematic from the CMIO board to have a slave/host USB port. My problem is the D+ and D- lines are ...
0
votes
0answers
38 views
Is there software with CAS to solve drawn electrical circuit in form of differential equations which describes that electrical circuit?
Is there any software with Computer Algebra System to solve drawn electrical circuit in the form of differential equations which describe that electrical circuit? Or to write symbolic solution (...
1
vote
0answers
38 views
Differential pair length matching considering phase
According to Microchip's document Implementation Guidelines for Microchip’s USB 2.0 and USB 3.1 Gen 1 and Gen 2 Hub and Hub-Combo Devices, the Superspeed differential pairs should be length matched ...
3
votes
2answers
86 views
Op amp differential amplifier output level too high
I'm trying to implement a current limiter for a buck converter charging a 2.7 V super capacitor. The design uses an op amp differential circuit that then feeds a comparator:
I have simulated the ...
0
votes
0answers
23 views
Inaccurate differential voltage measurement
I tested 3-level PFC voltage initialization event in practice using 1 x single ended probe to measure the output voltage as well as 3 x differential probes to measure the precharge voltage levels of ...
0
votes
2answers
86 views
creating a differential amplifier for low voltages (current shunt)
I'm trying to create a "precision" fully differential amplification stage, to measure uA on a 10R shunt, and mA on a 0.01R shunt. shunt resistance values are set at those values for burden ...
0
votes
1answer
59 views
How to make sense of the math behind differential opamp
My first question here!
So, I'm designing a simple fully differential amplifier. The final target will be to implement a low pass filter (but I'm not there yet). Although all seems perfectly fine in ...
0
votes
1answer
53 views
Understanding specifications
I have a differential signal which I want to measure with a differential probe.
While reading the specification of the probe, I got confused with a few terms.
Can someone what the highlighted terms ...
0
votes
0answers
48 views
What are these on the probes
I am having a Lecroy differential probe and trying to measure a LVDS signal. This is the Reference Manual which I am referring to as a guide.
My differential probe tip/lead model number : DX20 - SP/SI/...
2
votes
2answers
63 views
What kind of PLL is used to recover the clock from E.G. USB 2.0 data stream
I would like to create a communication protocol to connect two FPGAs. I would like it to be fairly fast, (a couple of 100s of Mbps) but only use a single differential pair.
This kind of thing is ...
1
vote
3answers
57 views
Using a power plane as signal reference
I am going to route Ethernet differential par in a four layer PCB which contains Top, PWR planes, GND plane and Bottom stackup. These diff pair are going to be routed in the top layer.
In order to ...
0
votes
0answers
38 views
Design Problem in differential Amp
It's my first attempt to design CMOS Differential amplifier in 0.35um technology using a cadence tool. I will explain my approach in deriving dimensions of MOSFET's used in it. Moreover, I have also ...
-1
votes
1answer
73 views
Difference in signal speed for a high speed signal when it is driven as single ended and differential?
This is a thought experiment. I would like know and what will be the bit-rate in differential channel when signal is driven differentially and in single ended mode?
Lets there is differential trace ...
1
vote
0answers
27 views
Differential Signal Measurement best practice
I have 4 differential signal pairs (LVDS Data lines and Clock) running between my Microcontroller and TFT. There are no test points over the lines.
Can someone tell me what is the best practice and ...
0
votes
1answer
22 views
LvPECL TX and LVDS RX
I have a quick sanity check question because it seems too good to be true.
If I have a LvPECL signal that I want to receive, I can just use a LVDS receiver (422/485 specifically) right? From reading ...
4
votes
2answers
635 views
Why do differential signals need an inverse wave?
At the moment, I'm working on converting a single ended audio signal to a differential one (source is a CS42L55, need a differential input for a CSR8670. The latter's datasheet is indecisive about how ...
0
votes
0answers
44 views
What's the difference between these two differential mode EMI filters?
When I search for differential mode input EMI filters (for power supplies), I get two different filter types:
simulate this circuit – Schematic created using CircuitLab
What's the difference ...
0
votes
1answer
43 views
Why this LVDS transceiver doesn't specify the differential input polarity?
I've been looking to implement a LVDS transceiver in my project where i can hook up to Displayport AUX differential pair.
I've discovered a suitable part, SN65MLVD200A in the following design ...
0
votes
1answer
45 views
Reading differential signals
By the circuit shown bellow I wanna read the ripple current by the 0.33 resistor and the ripple voltage of the capacitor by adding a low pass filter to reduce the spikes and a high pass filter to ...
3
votes
3answers
143 views
Confusion about differential amplifier configuration
As in the picture shows the signal applied at the base is say 1mv p-p, the circuit bias is not provided, then how this 1mv p-p able to forward bias the B-E junction?
0
votes
1answer
18 views
surface/external edge coupled microstrip vs (internal) asymmetric edge coupled microstrip
In the process of determining the track width/separation of differential pairs for a board design
that needs to route usb2, pcie(90R) , gigabit ethernet(100R), CSI/DSI(100R), HDMI
im looking a a four ...
0
votes
2answers
72 views
negative voltage of a differential amplifier
Can somebody explain what is this negative voltage -VEE in the circuit? I thought two parallel circuits are connected to the power supply vcc, but how this VEE came? Can somebody explain me this using ...
1
vote
2answers
310 views
Differential pair biasing by current sources
I'm having a problem understanding of how can a current be injected into emitter and pulled into collector via base, using only current sources at emitters and collectors of differential pair and not ...
0
votes
1answer
31 views
Shorter transmission lines or nearer high frequency bypass caps
I have an application where I have a sensor which communicates with an FPGA with about 15 differential pairs of data clocking around 300 Mhz. Due to constraints, the board can't be taller than 35mm ...
1
vote
0answers
56 views
Load curve control via differential pair
Last few weeks I have been designing a circuit, which is inputted with saw wave and outputs (amplification fairly linearly if possible) amplified voltage across two loads, where load voltage/current ...
2
votes
2answers
97 views
Is it possible to make a high-impedance voltage follower using a fully-differential op amp?
With a single-ended op amp, I can create a unity-gain voltage buffer like this:
simulate this circuit – Schematic created using CircuitLab
The input impedance of this circuit is equal to the ...
0
votes
1answer
54 views
Routing Differential Lines vs PCB Fabrication Constraints
I'm in front of a big question. I need to route 90 Ohms differential lines for a USB 2.0 Project.
I understand how to use tools like Saturn PCB Design to give me the correct spacing and lines width.
...
0
votes
0answers
19 views
Operation explanation of a low-swing differential receiver (amplifier)
The following figure shows an example of a low-swing differential receiver given in Hall's Advanced Signal Integrity for High Speed Digital Designs
However, I cannot figure out how this circuit works ...
0
votes
0answers
35 views
How to identify a coax connector vs twisted pair connector
I need to have a connector that will bring in COAX input to my PCB.
I have this Rosenberger HSD Connector Catalog.
On page 33, "99S12D-40MA5-y" - is this connector a twisted pair connector ...
0
votes
2answers
67 views
Please help me perform DC analysis of the attached circuit and derive equation for VB (Q1)
I am designing a differential pair with single supply source (Vcc), and I am very particular about not using split supply. I am using discrete current source for setting the tail current, and biasing ...
0
votes
2answers
70 views
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 ...
2
votes
1answer
84 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 ...
0
votes
0answers
50 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 ...
1
vote
2answers
62 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 ...
2
votes
2answers
199 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 ...
1
vote
1answer
30 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 ...
1
vote
3answers
94 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 ...
1
vote
0answers
49 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 ...
0
votes
0answers
41 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 ...
0
votes
1answer
33 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 ...
0
votes
0answers
67 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 ...
