AMD8513 datasheet(85/88 Pages) INFINEON

85 / 88 page

Data Sheet

Rev. 1.21, 2005-12-05

ADM8513

Data Sheet

Appendix Layout Guide

Trace routing

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Keep USB differential pair data signal D+ and D-:

– Trace width should be as wide as possible.

– Make D+ and D- traces route at the same signal plane and not pass through the other plane.

– Inhibit crossover on D+ and D-

– The termination resistance (R2,R3) and decoupling capacitors (C1,C2) should be closed to ADM8513/X.

– D+ and D- Signal trace length should be equal and as short as possible.

•

Arrangement Tx and Rx trace

– Tx+/- and Rx+/- trace avoid right angle and round angle >90 degree, suggested.

– Trace width must be wide and should be wider than 8 mils.

– Signal trace length between Tx+/- differential pairs should be crossed and have equal length.The total length

should be no longer than 2 cm. The same requirement applies to Rx+/- also.

– Make Tx and Rx trace route at the same signal plane and not pass through the other plane.

– Every differential pairs as cross as possible, but no less than 8 mils and space should be almost equal.

– Keep space large between Tx and Rx differential pairs, even separated ground planes underneath Tx and

Rx signal pairs.

– Away from clock and power traces.

– If Tx routed trace must cross, the trace can be swapped between chip and transformer, and transformer to

RJ45,too.

Figure 9

Trace Routing 1

Figure 10

Trace Routing 2

•

Digital signal should be away from analog signal and Vcc traces. If you can't avoid this situation, analog signal

or Vcc trace should cross over 90 degree at other plane.

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Good

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