Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [length-matching]

37 questions
16
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1 answer

Would it be considered good practice to match the lengths of UART's Tx/Rx traces?

I am assuming the answer would be yes since Tx/Rx pins are used to send data back and forth, or is it of such a low frequency that such thing is not required?
Alex
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4 answers

Meandering traces necessary for 24-Bit parallel RGB LCD interface?

I am working on a project that interfaces an Atmel SAMA5D3 MCU with a LCD TFT display. The interface between both is 24-Bit parallel RGB with HSYNC and VSYNC signals. The resolution of the display is 800x480 pixels. I understand that it is important…
Phillip Schuster
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3 answers

DDR(2-4) Training and Length Matching

Today I learned about the concept of memory training for DDR2, 3, and 4 (I'm not sure if DDR1 has it). The purpose of memory training is to correct for skew in data, address, and command bits being sent between controller and memory (presumably…
cr1901
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How much difference in net length is ok?

Sorry, but I couldn't find a better title. Consider the following: I have an address/data bus interface. Intended frequency of the D/A bus would be around 10-50MHz. According to the datasheet of the device in question (OMAP-L138) the maximum clock…
Tom L.
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4
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3 answers

PCB design for high-frequency differential lanes (PCIe and USB)

I have designed an M2 adapter which converts from KeyE to KeyM. Practically this means my board can be inserted into a KeyE slot, and it can host a KeyM SSD. Gray rectangle is the KeyM socket on my board: Design involves 10uF caps on 3.3V on both…
Daniel
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Does crystal leads have to be same length?

I have always managed to keep the length of crystal resonator leads at the similar length. In the application I am working atm however, I noticed it would be suitable to place the crystal in a way, that one of the leads would be significantly…
Łukasz Przeniosło
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3
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DDR Trace Length Inside Package from Simulation Model

The DDR4 in question is a Micron MT40A512M16JY. From the vendor site, you can get the datasheets, specs, sim models. I assume from the sim models you should be able to see the trace length of each signal pin inside the package. But I can't figure…
minghua
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1 answer

PCB data trace lengths tolerable difference for high frequency

I have to interface a camera to a controller using the DCMI protocol for my project. I have around 17 (data+control) lines which are used with the camera. The frequency of operation is about 10 MHz. I use EAGLE for my designs. However, while…
Sandra
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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 while considering phase. I.E. the length-matching…
Rocketmagnet
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differential pair impedance and length matching

I'm designing a high speed circuit (MIPI-DSI) so I have to carefully layout the tracks. Correct track impedance is the first point usually made in various online sources I've found on the subject, so I tried to get the microstrip impedance…
Genoil
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Quad-SPI (QSPI) net length mismatch

I am trying to make a good layout for the LAN9252 mac and STM32F7 controller, running at 80 MHz and I had to route data tracks with different lengths. The question is should I use nets lengths matching tool in QSPI at 80 MHz?
kvazibog
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Why is length matching important for high-speed signals?

Broadly speaking, I understand that PCB trace length matching is important from signal timing and signal integrity point of view, but I want to know some more specifics about these two parameters and if there are any other considerations and…
LoveEnigma
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PCB trace length matching for High Speed signals with known frequencies

I am designing a PCB with High speed video interfaces and I would like to know the way to calculate the maximum tolerance that I can count on while I am length matching all the traces. When I routed the signals from the DVI driver chip to the…
Dimitrios Torssøn
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Is it good practice to length match all traces of DDR3, or are only data traces important?

I am researching single board computers with the hope of designing on at the end of this, I am at the stage of DDR3, but can't find any good info on routing ddr3, regarding what traces need to be matched, and so on. Which traces need to be matched?…
Alex
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High-speed clock line crossing under data lines

I'm interfacing an SDI video de-serializer with an HDMI transmitter. The de-serializer splits the video signal into 20 parallel lines and one clock line. Because the digital video data is high speed (in the 100's of MHz), I'm working on matching the…
Dan Laks
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