Re: [N8VEM-S100:1271] LAVA-10 Zener Diode = 1N5226 (3.3v)

[yoda <yo...@r2d2.org>]

why not use 74lvxxx logic to interface to the lava board ? - it does the protection and is 5V tolerant - it has been used in propeller interfaces for the same thing and makes the parts count a lot smaller

On Sunday, January 6, 2013 11:51:09 AM UTC-6, lynchaj wrote:
> Hi Paul!  Thanks!  Yes, the 3.3VDC Zener diodes are added after the 100 ohm
> resistors for 5V to 3.3V level transition.  In theory you don't need them
> and adding the Zeners are kind of a "belt and suspenders" approach to level
> transition.  However the LAVA-10 is one expensive component so it is worth a
> the extra expense to protect it.  I'd consider them optional but a worthy
> investment even if not needed.
>
> Thanks and have a nice day!
>
> Andrew Lynch
>
> > -----Original Message-----
> > From: n8ve...@googlegroups.com [mailto:n8vem-
> > s1...@googlegroups.com] On Behalf Of Paul Birkel
> > Sent: Sunday, January 06, 2013 2:50 AM
> > To: n8ve...@googlegroups.com
> > Subject: [N8VEM-S100:1271] LAVA-10 Zener Diode = 1N5226 (3.3v)
> > 
> > Is it intended that 1N5226 (3.3v) Zener diodes be used for the logic-level
> > shifting circuits (with the 100 ohm resistors)?
> > 
> > -----