TUSB7340 datasheet(33/122 Pages) TI2

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proper operation. The package/case size of these capacitors should be no bigger than 0402. C-packs are not

allowed. The capacitors should be placed symmetrically as close as possible to the USB connector signal pins.

If a common mode choke is required, then place the choke as close as possible to the USB connector signal

pins (closer than the transmitter capacitors). Likewise, ESD clamps should also be placed as close as possible

to the USB connector signal pins (closer than the choke and transmitter capacitors).

It is permissible to swap the plus and minus on either or both of the SuperSpeed differential pairs. This may

be necessary to prevent the differential traces from crossing over one another. However, it is not permissible to

swap the transmitter differential pair with the receive differential pair.

TI recommends to use a 2010 pad for the inside pins provided no pad is used for adjacent pins. Instead use a

pad on one of the inside pins then for the next pad route the trace between the outer pins to a via.

To minimize cross-talk on the SS USB differential signal pair, it is recommended that the spacing between the

TX and RX signal pairs for each interface be five times the width of the trace (5-W rule). For instance, if the

SS USB TX differential pair trace width is 5 mils, then there should be 25 mils of space between the TX and

RX differential pairs. If this 5-W rule cannot be implemented, then the space between the TX and RX differential

pairs should be maximized as much as possible and ground-fill should be placed between the two. In this case, it

is better to route each differential pair on opposite sides of the board with a ground plane between them.

7.4.2 Layout Example

Figure 7-18. USB3 and USB2 Signals from the USB Connector to the Device

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TUSB7320, TUSB7340

SLLSE76Q – MARCH 2011 – REVISED MARCH 2024

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TUSB7340 数据表(PDF) 33 Page - Texas Instruments