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TMUXHS221: TMUXHS221

Part Number:TMUXHS221Other Parts Discussed in Thread: TUSB211A

你好,我们在使用TMUXHS221芯片作为USB2.0的切换时,发现信号在经过TMUXHS221之后眼图的中部有明显的塌陷导致眼图压模板,想请问一下,这里的塌陷是什么原因造成的,有没有改善的措施?

Amy Luo:

您好,

明天我会具体看下您的问题

,

Amy Luo:

很抱歉现在才回复您的问题,我在网上查 串联电阻会影响信号的幅值:

建议您按照 datasheet 如下截图中 layout 指南设计PCB :

最后这个文档 High-Speed Layout Guidelines for Signal Conditioners and USB Hubs application note 比较详细,建议您看下。

,

Hanlian Lv:

我这边关心的不是幅度的问题,主要是想问问后端塌陷的可能原因?

,

Amy Luo:

我想应该与 TMUXHS221的导通电阻和导通电容有关,我再问下更了解SI的TI 资深工程师。

,

Amy Luo:

这个问题似乎与Mux的回波损耗有关,不幸的是这是不能真正改变的。

看眼图我的最佳建议是加入TUSB21X redriver (如TUSB211A),并将其设置为最低的boost 设置,或查看信号的迹线看哪里可以缩短以减少迹线中的损失量。

The current issue seems to be related to the return loss of the mux, which is something that cannot really be changed unfortunately.

Looking at the eye, the best recommendations I have would be to incorporate a TUSB21X redriver, such as the TUSB211A, and set it to the lowest boost settings to better the AC timings of the signal, or to look at the trace of the signal, and see where it can be shortened to reduce the amount of loss in the trace.

Please let me know if you have any other questions.

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