Re: RS485 tranceivers?
From: Mac (foo_at_bar.net)
Date: 01/18/05
- Next message: Chuck Harris: "Re: Exportability of EDA industry from North America?"
- Previous message: Brian: "Re: OT? : Finding those "hidden" customers."
- In reply to: Anders F: "Re: RS485 tranceivers?"
- Messages sorted by: [ date ] [ thread ]
Date: Tue, 18 Jan 2005 03:37:43 GMT
On Sun, 16 Jan 2005 23:39:52 +0100, Anders F wrote:
> "Mac" <foo@bar.net> wrote in message
> news:pan.2005.01.16.05.08.01.778535@bar.net...
>> On Sun, 16 Jan 2005 05:48:28 +0100, Anders F wrote:
>>
>>> "valentin tihomirov" <spam@abelectron.com> wrote in message
>>> news:34u2hgF4esemlU1@individual.net...
>>>>> Yep - then why wouldn't they make tranceivers this range too? I mean
>>>>> the
>>>>> differential drivers can be made as 3.3V and 5V...
>>>>
>>>> Actually, most rs422/485 drivers use these logic levels.
>>>
>>> Yeah - but they're either specified for 3.3V OR 5V (it's the supply I'm
>>> referring to). I'm wondering why the device I need (3-5V supply range)
>>> does
>>> not exsist....
>>>
>>> /A
>>
>> Well, I think the rs (or actually EIA) 422 specification specifies what
>> the complementary (they're usually NOT differential) voltage levels are
>> supposed to be.
>>
>> As far as 3.3 and 5 V levels go, almost any device designed to work
>> at a nominal 3.3V will be specified to work down to 3V (usually the fine
>> print will say 3.3V +/- 10%). And any CMOS device which works at 3.3V AND
>> 5V will work everywhere in between, as long as it is interfaced to devices
>> connected to the same rail.
>
> The problem is they are EITHER 3.3V or 5V types.
>
>> Maybe you could post a specific part number and a little more
>> information about your application.
>
> Well, at the moment the MAX3072E is the more promising.
> Similar types from TI and a lot of pincompatible 5V types have also been
> investigated
>
>> Then you might get some meaningful
>> feedback about whether your application is likely to work.
>
> The application involves a lot of units supplied through a ribbon cable.
> Thus, I'd like to save the power, cost and complexity of having to output
> excess power and dissipating this in a LDO. If I had 3-5.5V types the say
> 0-1V drop over the cable could easily be tolerated....
>
Hmm. I wonder if you could just use a 5V type at 3.3 V? What baud rate are
you running at? If it is slow I bet it would work, particularly if you are
not going over long cables, and are only interacting with devices of your
own design. I would definitely try asking an applications engineer from
the relevant company.
> Cheers,
> Anders
Good luck.
--Mac
- Next message: Chuck Harris: "Re: Exportability of EDA industry from North America?"
- Previous message: Brian: "Re: OT? : Finding those "hidden" customers."
- In reply to: Anders F: "Re: RS485 tranceivers?"
- Messages sorted by: [ date ] [ thread ]
Relevant Pages
|
