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We're talking about isolator speed,
with Sandy, in the NVE Application Center. 

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Sandy: PWD, skew, jitter.
All the terms give me the "jitters."

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So let's cover key isolator speed metrics. 

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Starting with data rate, which is the maximum rate
at which data can be transmitted.

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Simple enough,

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but some companies specify a data rate
faster than the propagation delay. 

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This is a waveform for an actual device. 

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The data is more than five cycles behind.

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By the time the data shows up on the output,

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not only are we on the next clock cycle,
it's several cycles behind.

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And other parameters
can make claimed data rate unusable. 

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For example, one competitor's datasheet
requires zero rise and fall time,

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and EXACTLY 50% duty cycle. Obviously unrealistic.

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That's so lame. NVE would never do that...

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That's why "Usable Data Rate" is important.

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UDR is defined as the maximum rate
before the data is a clock cycle behind. 

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So with this propagation
delay the full data rate is usable.

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Gotcha. And how is "Propagation Delay" defined?

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Righty-O. "Propagation Delay" is the time
for an edge to propagate. 

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The faster the device the shorter the prop delay.

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There are also some important metrics
related to prop delay.

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Because fast is worthless if it's garbled.

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"Pulse-Width Distortion" is the maximum difference
in rising and falling prop delays. 

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As you can see,
the asymmetry distorts the pulse width,

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in this case, making it wider. 

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This is important in pulse width modulation and
delta-sigma ADCs.

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"Channel-to-Channel Skew" is the difference
in propagation delay between channels

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in the same device. It can be either direction.
It's critical in clocked systems.

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"Propagation Delay Skew" is the difference
in propagation delay between devices. 

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Also important for clocked systems. It's larger
than "Channel-to-Channel Skew," and can be

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a trap for the unwary in synchronous systems.
This is an area where IsoLoop isolators shine.

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Finally, "jitter" is another under-reported parameter.
It's the variation in the pulse edge position

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and can cause particularly nasty distortion.

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So, what are some specs for those parameters?

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Here are the specs for NVE's
IsoLoop IL700-S Series parts:

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"Data Rate"; and "Usable Data Rate"
are the same for NVE isolators;

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"Propagation Delay"
is the time for an edge to propagate;

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"Pulse-Width Distortion"
is the change in pulse width at the output;

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"Propagation Delay Skew" is the difference
in propagation delay between devices;

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"Channel-to-Channel Skew" is the difference

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in propagation delay between channels
in the same device; 

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and "Jitter" is the variation
in the pulse edge position.

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The NVE parts are best in class.
for speed parameters.

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Thanks, Sandy. Where do you "propagate" more
"unskewed," "usable" info?

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You can go to nve.com, 

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or call us, at 800-GMR-7141, extension 4.