FPGA Central

Greetings everyone,
*
I am currently looking at SATA and SAS SerDes designs.* It looks like the data transmission is AC coupled.* Is this a standards requirement ?*
*
Could anyone enlighten me on why SATA/SAS specifies only AC coupled links [if that is in fact the case]; i.e. what was the thinking/justification for restricting transmission to ac coupled only.
*
Also, do the other standards :* Gbit Ethernet, PCI Express, RapidIO, etc. have similar restrictions/requirements ?
*
Thanks v much in advance,
*
Alief


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Alief,

AC coupling is needed to maintain the correct DC bias for receivers. If your transmitter has 0V DC bias, then I guess you don't have to implement AC coupling.

TK

-----Original Message-----
From: si-list-bounce (AT) freelists (DOT) org [mailto:si-list-bounce (AT) freelists (DOT) org] On Behalf Of Alief
Sent: Thursday, May 07, 2009 10:46 AM
To: si-list (AT) freelists (DOT) org
Subject: [SI-LIST] AC coupling of SATA and SAS I/O

Greetings everyone,
*
I am currently looking at SATA and SAS SerDes designs.* It looks like the data transmission is AC coupled.* Is this a standards requirement ?*
*
Could anyone enlighten me on why SATA/SAS specifies only AC coupled links [if that is in fact the case]; i.e. what was the thinking/justification for restricting transmission to ac coupled only.
*
Also, do the other standards :* Gbit Ethernet, PCI Express, RapidIO, etc. have similar restrictions/requirements ?
*
Thanks v much in advance,
*
Alief


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Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu


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Old (prior to June 6, 2001) list archives are viewable at:
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