ACSL-6210-06R Avago Technologies US Inc., ACSL-6210-06R Datasheet - Page 18

• Manufacturer Part Number: ACSL-6210-06R
• Description: Bi-Dir Digital Optocoupler
• Manufacturer: Avago Technologies US Inc.

Specifications of ACSL-6210-06R

• Voltage - Isolation: 2500Vrms
• Number Of Channels: 2, Bi-Directional
• Current - Output / Channel: 50mA
• Data Rate: 15MBd
• Propagation Delay High - Low @ If: 44ns @ 8mA
• Current - Dc Forward (if): 15mA
• Input Type: DC
• Output Type: Open Collector
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-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 propaga- tion delay from low to high
(t
propagate to the output,causing the output to change
from low to high. Similarly,the propagation delay from
high to low (t
input signal to propagate to the output causing the
output to change from high to low (see Figure 16).
Pulse-width distortion (PWD) results when t
in value. PWD is defined as the difference between t
t
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-l, etc.).
Propagation delay skew,t
to consider in parallel data applica- tions where synchro-
nization of signals on parallel data lines is a concern. If
the parallel data is being sent through a group of op-
tocouplers, 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 optocou-
plers.
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.,
Figure 23. Propagation delay skew – t
18
PHL
PLH
and often determines the maximum data rate capability
) is the amount of time required for an input signal to
PHL
PLH
) is the amount of time required for the
or t
PHL
, for any given group of optocou-
PSK
PSK
.
, is an important parameter
PLH
and t
PHL
PLH
differ
and
the same drive current, supply voltage, output load, and
operating temperature). As illustrated in Figure 23, if the
inputs of a group of optocouplers are switched either ON
or OFF at the same time, t
shortest propagation delay,either t
longest propagation delay,either t
As mentioned earlier,t
parallel data transmission rate. Figure 24 is the timing
diagram of a typical parallel data application with both
the clock and the data lines being sent through opto-
couplers. 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 repre- sents the uncertainty of
where an edge might be after being sent through an op-
tocoupler. Figure 24 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 application
is twice t
pulse width to ensure that any additional uncertainty in
the rest of the circuit does not cause a problem.
The t
guaranteed specifications for propagation delays, pulse-
width distortion and propagation delay skew over the
recommended temperature, input current, and power
supply ranges.
Figure 24. Parallel data transmission example.
PSK
specified optocouplers offer the advantages of
PSK
. A cautious design should use a slightly longer
PSK
PSK
can determine the maximum
is the difference between the
PLH
PLH
or t
or tPHL, and the
PHL
.