Figure 15. Illustration of T
PSK
For product information and a complete list of distributors, please go to our web site: www.avagotech.com
Avago, Avago Technologies, and the A logo are trademarks of Avago Technologies in the United States and other countries.
Data subject to change. Copyright © 2005-2011 Avago Technologies. All rights reserved.
AV02-2675EN - May 16, 2011
Pulse-width distortion (PWD) is the di erence between
t
PHL
and t
PLH
and often determines the maximum data
rate capability of a transmission system. PWD can be
expressed in percent by dividing the PWD (in ns) by the
minimum pulse width (in ns) being transmitted. Typically,
PWD on the order of 20-30% of the minimum pulse
width is tolerable. The PWD speci cation for ACML-7400
series is 3 ns maximum across recommended operating
conditions.
Propagation delay skew, t
PSK
, is an important parameter
to consider in parallel data applications where synchro-
nization of signals on parallel data lines is a concern. If
the parallel data is sent through a group of isolators, dif-
ferences in propagation delays will cause the data to
arrive at the outputs of the isolators at di erent times. If
this di erence in propagation delay is large enough it will
determine the maximum rate at which parallel data can
be sent through the isolators.
Propagation delay skew is de ned as the di erence
between the minimum and maximum propagation
delays, either t
PLH
or t
PHL
for any given group of optocou-
plers which are operating under the same conditions (i.e.,
the same drive current, supply voltage, output load, and
operating temperature). As illustrated in Figure 15, if the
inputs of a group of isolators are switched either ON or
OFF at the same time, t
PSK
is the di erence between the
shortest propagation delay, either t
PLH
or t
PHL
and the
longest propagation delay, either t
PLH
and t
PHL
.
The ACML-7400 series isolators o er the advantage of
guaranteed speci cations for propagation delays, pulse-
width distortion, and propagation delay skew over the
recommended temperature and power supply ranges.
t
PSK
50%
50%
V
DD2
50% V
DD2
50%
V
IN
V
OUT
V
IN
V
OUT
