Purpose of USB_RTUNE resistor

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WGF2Intra
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Purpose of USB_RTUNE resistor

Post by WGF2Intra »

The XEF216-512-TQ128 datasheet specifies (on page 17) that a 43.2 Ohm, 1% pull-down resistor should connect USB_RTUNE to ground. What is the purpose of this resistor? Is it needed if the USB PHY is not being used?
henk
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Post by henk »

Hi WGF2Intra,

That resistor is needed to make the USB PHY operate properly. You can omit it if you never enable the USB PHY.

Cheers,
Henk
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infiniteimprobability
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Post by infiniteimprobability »

If you're interested, the specific reason for the resistor is a precise reference resistance for the termination circuitry inside the PHY...