[Mahen K]

On Aug 16, 10:42*pm, Dick Pierce wrote:
Mahen K wrote:
Hi,

Digital Audio receiver ICs like DIR9001 and CS8414 mention the diff
voltage level at their input pins RXP and RXN as 200mv min while the
Digital Audio Transsmitters like DIT4096 and CS8406 use *5V logic
levels. How are they compatible with wide difference in levels? I am
looking at using them for SPDIF transmission and reception.

*From IEC 958 5.3.3.3 "Minimum input signals",

* * Minimum input voltage shall be 0.2V peak-to-peak

That is, the MINIMUM input voltage.

Now, if you actually read the specs for, oh, the DIT4096,
you might discover that even though the "core voltage" is
5 volts, a figure more relevant to your issues is the
"high-level output voltage Voh" which is listed at 0.8V

Further inspection of the spec sheet reveals, in figure
11, a block referred to as the "output circuit," which
is elucidated in figures 12, 13 and 14. FIgure 13 is,
again, most relevant to your question. It shows the
output circuit for a SP/DIF circuit, consisting,
significantly of a 2:1 step-down pulse transformer,
which would make it completely compatible with the
IEC 958 standard.

Aren't spec sheets wonderful?

--
+--------------------------------+
+ * * * * Dick Pierce * * * * * *|
+ Professional Audio Development |
+--------------------------------+

Thanks for quick response. I couldn't find Voh as 0.8v anywhere in the
DIT4096 datasheet?? Page 3 of the datasheet says Voh for TX+ and TX-
as Vdd - 0.4v which translates to 4.6v. With 4.6V and 2:1 transfo o/p
is around 2.3v which is not compatible with consumer spdif inputs
unless I am missing something. Also, I just looked at the datasheet of
SRC4392 which says RX1+ and RX1- input levels are 200mv max. This
clearly will not work with the aboev scheme.

-mjnk