Dear all, Please tell me how LVDS drivers with cables can damaged? Possible cases are: 1 - Power supply under/overshoots. 2 - ESD on cables. 3 - Missing hot-plugging. e.g. connect GND, then signal, then power. 4 - Killer spikes on power supply rail or input/outputs. 5 - ? Regards.
How LVDS Drivers kills?
Started by ●December 15, 2003
Reply by ●December 15, 20032003-12-15
Masoud,
Can you tell me more about the failure mode?
NJ
"Masoud Naderi" <naderimisc@yahoo.com> wrote in message
news:2ba3bbea.0312150037.12810136@posting.google.com...
> Dear all,
> Please tell me how LVDS drivers with cables can damaged?
> Possible cases are:
> 1 - Power supply under/overshoots.
> 2 - ESD on cables.
> 3 - Missing hot-plugging. e.g. connect GND, then signal, then power.
> 4 - Killer spikes on power supply rail or input/outputs.
> 5 - ?
>
> Regards.
Reply by ●December 16, 20032003-12-16
Hi, Our LVDS Drivers failed when their power supply starts(it has soft start feature). On some boards only positive output or input of differential side failed (probably because of high current sourcing in failure mode). I checked power suppply yesterday and found some negative (-2.7v) but very narrow (200ns) spikes on power supply rail. I think it is one of the problems. LVDS drivers are from TI and spikes below -0.5 damage them. I look for more problem, e.g. grounding and ... here are some shematic of our system: LVDS+/- <-............3meter twisted-pair cable...............-> LVDS+/- GND ----------------------------------------------------------> GND regards
Reply by ●December 18, 20032003-12-18
This sounds like a grounding problem, whose LVDS drivers are you using? "Masoud Naderi" <naderimisc@yahoo.com> wrote in message news:2ba3bbea.0312152232.5d87d9d2@posting.google.com...> Hi, > Our LVDS Drivers failed when their power supply starts(it has soft > start feature). On some boards only positive output or input of > differential side failed (probably because of high current sourcing in > failure mode). > I checked power suppply yesterday and found some negative (-2.7v) but > very narrow (200ns) spikes on power supply rail. I think it is one of > the problems. LVDS drivers are from TI and spikes below -0.5 damage > them. I look for more problem, e.g. grounding and ... > > here are some shematic of our system: > > LVDS+/- <-............3meter twisted-pair cable...............-> > LVDS+/- > GND ----------------------------------------------------------> GND > > regards >
Reply by ●December 21, 20032003-12-21
Hi, I measured ground voltage difference between two side of cable, it was very small (<0.1V). However I like to install a low impedance( againt high frequency noises) cable between two racks, but I have not acceptable reasons for this! please guide me on this. regards. "tbx135" <tbx135@msn.com> wrote in message news:<%DtEb.42912$yp5.14836@newssvr31.news.prodigy.com>...> This sounds like a grounding problem, whose LVDS drivers are you using? > > "Masoud Naderi" <naderimisc@yahoo.com> wrote in message > news:2ba3bbea.0312152232.5d87d9d2@posting.google.com... > > Hi, > > Our LVDS Drivers failed when their power supply starts(it has soft > > start feature). On some boards only positive output or input of > > differential side failed (probably because of high current sourcing in > > failure mode). > > I checked power suppply yesterday and found some negative (-2.7v) but > > very narrow (200ns) spikes on power supply rail. I think it is one of > > the problems. LVDS drivers are from TI and spikes below -0.5 damage > > them. I look for more problem, e.g. grounding and ... > > > > here are some shematic of our system: > > > > LVDS+/- <-............3meter twisted-pair cable...............-> > > LVDS+/- > > GND ----------------------------------------------------------> GND > > > > regards > >
Reply by ●December 21, 20032003-12-21
Read this: http://www.national.com/an/AN/AN-1085.pdf -2.7V spikes for 200 ns "Masoud Naderi" <naderimisc@yahoo.com> wrote in message news:2ba3bbea.0312210846.3ed95f90@posting.google.com...> Hi, > I measured ground voltage difference between two side of cable, it was > very small (<0.1V). However I like to install a low impedance( againt > high frequency noises) cable between two racks, but I have not > acceptable reasons for this! > please guide me on this. > regards. > > > "tbx135" <tbx135@msn.com> wrote in messagenews:<%DtEb.42912$yp5.14836@newssvr31.news.prodigy.com>...> > This sounds like a grounding problem, whose LVDS drivers are you using? > > > > "Masoud Naderi" <naderimisc@yahoo.com> wrote in message > > news:2ba3bbea.0312152232.5d87d9d2@posting.google.com... > > > Hi, > > > Our LVDS Drivers failed when their power supply starts(it has soft > > > start feature). On some boards only positive output or input of > > > differential side failed (probably because of high current sourcing in > > > failure mode). > > > I checked power suppply yesterday and found some negative (-2.7v) but > > > very narrow (200ns) spikes on power supply rail. I think it is one of > > > the problems. LVDS drivers are from TI and spikes below -0.5 damage > > > them. I look for more problem, e.g. grounding and ... > > > > > > here are some shematic of our system: > > > > > > LVDS+/- <-............3meter twisted-pair cable...............-> > > > LVDS+/- > > > GND ----------------------------------------------------------> GND > > > > > > regards > > >
