Questions tagged [controlled-impedance]
The controlled-impedance tag has no usage guidance.
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How are pad impedance discontinuities precisely compensated for in high speed PCB layouts?
I stumbled across a recommendation in an 850MHz opamp datasheet that said the following:
All ground and power planes under the input and output pins must be cleared of copper to prevent the formation ...
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Altium coplanar waveguide ground clearance rules
I am trying to route 50 Ohm coplanar waveguides in Altium for some 2.45GHz circuits. I have defined my stackup and impedance requirements via the layer stackup manager / impedance calculator, and have ...
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USB series resistors
I have 2 questions:
The USB differential pair D+/D- are impedance-controlled 90 Ohm transmission line..
Why do I need to put a 22 Ohm series termination resistor in it?
Isn't that a discontinued ...
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Formula for coupled stripline of 100 ohm
I am designing a PCB which involves MIPI and LVDS routing.
What is the formula to calculate the impedance of asymmetric coupled stripline for MIPI and LVDS routing (100 ohm)? The required calculator ...
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Routing ethernet differential pairs over ground plane
I am routing a flexible PCB which connects a panel-mount ethernet connector (without integrated magnetics) to a rigid PCB which contains the ethernet magnetics. I plan to route the differential pairs ...
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Trace impedance for two signal layers between ground planes
When watching a few videos about stackup, EMI and impedance (especially this video from Fedevel Academy: https://youtu.be/52fxuRGifLU), I got confused how to compute trace impedance in the case of two ...
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Unattached tails (stubs) on SPI lines
I have a circuit design coming together that uses either of 2 sockets to plug in a controller. The idea is to allow a user to enable either of the controllers to control a radio using SPI. In the ...
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When to Remove the Ground Plane under SMD components for High-Speed Signals?
I'm reading TI's recommendations on routing high-speed signals. Most of the guidelines are common sense, but there's one guideline that I haven't read before: It recommends completely removing the ...
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Which Signals require impedance matching?
There are two types of connections in PCB.
Which are in between the PCB.(e.g- A SD card is connected near to Controller)
One is going out through some connectors.(Some UART or SPI going out through ...
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Controlled impedance/coplanar wave design
We're using Diptrace at work which has no support for controlled impedance tracks.
I'm making a small 2 layer pcb for a TDR pulse generator, and would like to make one track about 50ohms impedance.
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How much RF power can a microstrip line handle?
Transmission lines on printed circuit boards must be impedance controlled lines since we want to transmit the full power and avoid the reflections.
Microstrip lines have three parameters that we can ...
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Trace impedance on 4layers (Top and internal_plane_1)
I'm currently design a 4layers pcb with 50r trace for an Ceramic chip antenna (on top layer).
Due of a lot of trace, my trace antenna is a coplanar.
Trace on top layer with polygon pour around AND ...
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Pads reflecting in controlled impedance strip?
Background
I'm designing a controlled impedance line for a 1900MHz signal travelling between SIM7000A cellular chip and an antenna.
Question
Tuning circuits are recommended for antennas with series ...
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PCB Thickness Variability
How much variability is there in the thickness of a standard PCB?
Let's say I order a 1.6mm FR-4 board. Will the actual thickness range 1.5mm-1.7mm? 1.4mm-1.8mm? 1.59mm-1.61mm? What is the (...
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Altium - design rule check does not match with signal integrity for impedance
I have designed a 2-layer PCB with Altium Designer. I placed an impedance rule of 50 Ohm in trace width rule section. When I run the design rule check, there is no impedance error.
However, when I ...
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