Re: 3.3V-5V level ****fters

On Sep 25, 3:26=A0am, Joerg <notthisjoerg...@[EMAIL PROTECTED]
>
wrote:
> What's the jelly-bean level ****fter du jour, the most popular?

Don't know that but recently I designed in some 74LVXC3245, yet to
power the first board with them, though. But I am pretty experienced
with that sort of thing and did not smell anything foul (and I hope
saying so now won't come and bite me in 2-3 weeks time when I
have the prototype board here...).

> Need to ****ft three sigs 3.3V to 5V and another three 5V to 3.3V.

Will do - but will take two chips if you need to simultaneously
have both directions actively driven. The two sides are separately
powered which should make sure no thermal issues like those John
mentioned are to be expected.

> The topper is a comment in the TXB spec, "OE should be tied to GND
> through a pulldown resistor; the minimum value of the resistor is
> determined by the current-sourcing capability of the driver" That driver
> is obviously on the chip. Duh! Of course they also forgot what to do if
> not needed. Pull up? Leave open? Who knows. Well, maybe they had a
> kegger the night before ...

You must have overlooked something there. OE should be an input
only - must be held low for the drivers to be open - the drivers on
the 16 data pins, that is. Drive it high and all get tristated.

Didi

------------------------------------------------------
Dimiter Popoff               Transgalactic Instruments

http://www.tgi-sci.com
------------------------------------------------------
http://www.flickr.com/photos/didi_tgi/sets/72157600228621276/

Original message:
http://groups.google.com/group/sci.electronics.design/msg=
/0dacf2ff0fd37552?dmode=3Dsource