All Questions
Tagged with differential usb
38
questions
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39
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Impedance controlled PCB for USB 2.0?
We're doing a PCB for a customer that has Impedance controlled tracks for a microcontroller that seemingly might be max USB2.0, judging from lack of multiple data lines and the fact it goes in a micro-...
- 320
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41
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M-LVDS differential signals through multiplexers
I'm experimenting with M-LVDS via USB 3.1 cables, passing the differential signals through the SuperSpeed lanes. I'm using the DS91M040 for driving M-LVDS. So far no issues, however, I need now to ...
- 423
5
votes
5
answers
978
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Is the voltage on the negative of a differential pair actually below the ground voltage used to generate the signals?
Apologies if it’s obvious but I always hear that differential pairs have a negative and positive waveform (one on each line) that’s opposite. Now I get that you could choose whatever value or point “...
- 667
2
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61
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USB to FTDI connection
I try to connect USB 2.0 to a FTDI FT2232HL. This is my first high speed layout.
I am planning to use 2-layer board 1.6 mm. I know that I have to keep 50 Ω Z0 and 90 Ω Zdiff. However with the 2-layer ...
- 21
6
votes
2
answers
1k
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USB (low speed) on stripboard: can it work?
I recently designed a PCB, with a connector for an extension module for "future uses" (with various signals: GPIOs, I2C, SPI, USB2.0, USB3.1, PCIe Gen4).
The connectors are fine pitched (and ...
- 7,697
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1
answer
166
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Weird pinout of USB ESD protection
The USB ESD protection component USBLC6-2SC6 seems to be very popular (?). However, its pinout seems not ideal:
The USB differential pair should be routed close to each other, but the pinout of ...
- 149
2
votes
1
answer
426
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Does USB3.0 support reverse polarity in SSTX and SSRX?
Is it possible to Sawp the +/- pins of SSRX and SSTX to make the routing easier and avoid using vias? Does USB3.0 support this reverse polarity?
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404
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Correct Dielectric Height on Differential Impedance Calculation?
I'm designing a custom PCB around the Raspberry Pi RP2040 MCU. Their hardware design guideline said the traces between the USB and the termination resistors should have a differential impedance of 90 ...
- 495
-1
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1
answer
256
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Micro USB and RS485 Compatibility
I am looking into understanding micro usb better and seem to be missing something apparently obvious different about the difference between micro usb and rs485.
From looking online like here, the ...
- 111
1
vote
2
answers
1k
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Do I need to worry about single-end impedance in a differential pair?
The title says the question.... I don't quite understand the need for a single-end impedance if I'm routing a differential pair. What I mean is, if I need to route a differential pair on a circuit ...
user224284
1
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406
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How important is 'perfectly' phase matching high speed differential lines?
This question is related to 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 ...
- 27.5k
1
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1
answer
3k
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What value series resistor should I use for USB data lines when two ICs require different impedance values?
I'm using a USB hub (TUSB2036VFR) that communicates with an ATMEGA8U2 and an FTDI chip. The incoming USB signal comes through an isolated USB communications chip ADUM3160BRWZ. The TUSB2036VFR requires ...
- 1,058
1
vote
1
answer
331
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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 ...
- 27.5k
0
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0
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215
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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 ...
2
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596
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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 ...
- 27.5k