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Audio and Video Talk
Digital
My next experiment re digital audio.
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<blockquote data-quote="pwatts" data-source="post: 752522" data-attributes="member: 146"><p>This has to be clarified. USB3 has zero in common with USB2, and if one looks at the connector pinouts it's clear that it's all duplicated. USB3 has its own data pins and actually a USB3 connector houses a completely independent set of USB2 pins. All that is shared is ground, power and shell (earth).</p><p></p><p>USB3 needs to be able to deliver more current, but it all comes from the same PC 5V bus, which then passes through a current-limited load switch to turn off the current when exceeding the spec. As long as the current limit is not exceeded there's no difference and the "purity" of the current is the same regardless since it's just fed from the PC PSU.</p><p></p><p>There is a far more plausible reason for this though: because of this higher current ability, a USB3 host port typically has higher capacitance on the power rail of better quality than USB2. The spec says 120uF minimum, and for most USB2 applications a cheap and nasty electrolytic is used. For USB3, designers tend to opt for something a little larger and with better ESR specs to pass qualification.</p></blockquote><p></p>
[QUOTE="pwatts, post: 752522, member: 146"] This has to be clarified. USB3 has zero in common with USB2, and if one looks at the connector pinouts it's clear that it's all duplicated. USB3 has its own data pins and actually a USB3 connector houses a completely independent set of USB2 pins. All that is shared is ground, power and shell (earth). USB3 needs to be able to deliver more current, but it all comes from the same PC 5V bus, which then passes through a current-limited load switch to turn off the current when exceeding the spec. As long as the current limit is not exceeded there's no difference and the "purity" of the current is the same regardless since it's just fed from the PC PSU. There is a far more plausible reason for this though: because of this higher current ability, a USB3 host port typically has higher capacitance on the power rail of better quality than USB2. The spec says 120uF minimum, and for most USB2 applications a cheap and nasty electrolytic is used. For USB3, designers tend to opt for something a little larger and with better ESR specs to pass qualification. [/QUOTE]
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Audio and Video Talk
Digital
My next experiment re digital audio.
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