ACPL-M61U-000E Avago Technologies US Inc., ACPL-M61U-000E Datasheet - Page 11

• Manufacturer Part Number: ACPL-M61U-000E
• Description: 10MBd Coupler, Pb-Free
• Manufacturer: Avago Technologies US Inc.
• Series: R²Coupler™r

Specifications of ACPL-M61U-000E

• Voltage - Isolation: 3750Vrms
• Number Of Channels: 1, Unidirectional
• Current - Output / Channel: 50mA
• Data Rate: 10MBd
• Propagation Delay High - Low @ If: 46ns @ 6.5mA
• Current - Dc Forward (if): 20mA
• Input Type: DC
• Output Type: Open Collector
• Mounting Type: Surface Mount
• Package / Case: SO-5 (MO-155)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Propagation Delay, Pulse-Width Distortion and Propagation Delay Skew
Propagation delay is a figure of merit which describes
how quickly a logic signal propagates through a system.
The propagation delay from low to high (t
amount of time required for an input signal to propagate
to the output, causing the output to change from low to
high. Similarly, the propagation delay from high to low
(t
to propagate to the output, causing the output to change
from high to low (see Figure 6).
Pulse-width distortion (PWD) results when t
differ in value. PWD is defined as the difference between
t
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 exact figure depends on the particular
application (RS232, RS422, T-1, etc.).
Propagation delay skew, t
to consider in parallel data applications where synchroni-
zation of signals on parallel data lines is a concern. If the
parallel data is being sent through a group of optocou-
plers, differences in propagation delays will cause the data
to arrive at the outputs of the optocouplers at different
times. If this difference in propagation delays is large
enough, it will determine the maximum rate at which
parallel data can be sent through the optocouplers.
Propagation delay skew is defined as the difference
between the minimum and maximum propagation
delays, either t
plers which are operating under the same conditions (i.e.,
the same drive current, supply voltage, output load, and
Figure 14. Illustration of Propagation Delay Skew – t
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Data subject to change. Copyright © 2005-2010 Avago Technologies. All rights reserved.
AV02-0950EN - September 23, 2010
V
V
I
I
PLH
F
F
O
O
PHL
) is the amount of time required for the input signal
and t
PHL
and often determines the maximum data
PLH
50%
50%
or t
1.5 V
PHL
, for any given group of optocou-
PSK
t
, is an important parameter
2
PSK
Coupler™ are trademarks of Avago Technologies in the United States and other countries.
PSK
1.5 V
PLH
PLH
and t
) is the
PHL
www.avagotech.com
operating temperature). As illustrated in Figure 14, if the
inputs of a group of optocouplers are switched either ON
or OFF at the same time, t
the shortest propagation delay, either t
the longest propagation delay, either t
As mentioned earlier, t
parallel data transmission rate. Figure 15 is the timing
diagram of a typical parallel data application with both
the clock and the data lines being sent through optocou-
plers. The figure shows data and clock signals at the inputs
and outputs of the optocouplers. To obtain the maximum
data transmission rate, both edges of the clock signal are
being used to clock the data; if only one edge were used,
the clock signal would need to be twice as fast.
Propagation delay skew represents the uncertainty of
where an edge might be after being sent through an op-
tocoupler. Figure 15 shows that there will be uncertainty
in both the data and the clock lines. It is important that
these two areas of uncertainty not overlap, otherwise the
clock signal might arrive before all of the data outputs
have settled, or some of the data outputs may start to
change before the clock signal has arrived. From these
considerations, the absolute minimum pulse width that
can be sent through optocouplers in a parallel applica-
tion is twice t
longer pulse width to ensure that any additional uncer-
tainty in the rest of the circuit does not cause a problem.
The t
of guaranteed specifications for propagation delays,
pulse-width distortion and propagation delay skew over
the recommended temperature, and input current, and
power supply ranges.
Figure 15. Parallel Data Transmission Example
OUTPUTS
INPUTS
CLOCK
CLOCK
DATA
DATA
PSK
specified optocouplers offer the advantages
PSK
t
PSK
. A cautious design should use a slightly
t
PSK
PSK
PSK
can determine the maximum
is the difference between
PLH
PLH
or t
or t
PHL
.
PHL
, and