110Mbs High speed digital isolators

I came across these while repairing a Keithley 2001. Pretty neat device as it beats out opto-couplers by a factor of 10 or so.

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Thought they might be of some interest.

Reply to
JW
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On a sunny day (Mon, 07 Jan 2013 07:22:39 -0500) it happened JW wrote in :

Looks very interesting, but I do not see how 'recommended operating conditions' on page 2 can say 1us rise and fall time for the input signal, as that results in

Reply to
Jan Panteltje

On a sunny day (Mon, 07 Jan 2013 13:16:45 GMT) it happened Jan Panteltje wrote in :

Never mind, figured it out, is max rise and fall times.

Reply to
Jan Panteltje

They're neat devices. The only weird thing is the ambigous power-on state, but they share that with some other isolation schemes.

Best regards, Spehro Pefhany

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"it's the network..."                          "The Journey is the reward" 
speff@interlog.com             Info for manufacturers: http://www.trexon.com 
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Reply to
Spehro Pefhany

Interesting, GMR. GMR being static, they could've made it DC stable (if not necessarily appealing on current consumption), but they chose to do it by pulse instead. GMR may be sensitive to DC fields, though they don't specify.

The ADI magnetic isolators are about as fast (I think one is 50Mbps, but they may have up to 100, I haven't looked in detail). They're also stable at DC, in the presence of DC fields (basically until hall effect craps out the silicon itself), and have higher isolation ratings (5kV RMS short duration).

This device's susceptibility appears to be about independent of frequency, which may be useful.

Strange that they measure note 10: surely a PRBS with no more than 5 consecutive digits is only a 5 bit generator, not 66,535; and surely they mean 65535, and surely they mean 16 bit = 65535 state, not 65535 bits?

Tim

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Deep Friar: a very philosophical monk. 
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Reply to
Tim Williams

Analog Devices has had isolators similar to that for some time (e.g. ADUM1100). I used some of their "ISO-Power" isolators a couple years ago. These include an isolated power supply (150mA) and go up to

150Mbps (e.g. ADUM5210). Quite pricey, though (they start at $5, IIRC).
Reply to
krw

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I think what they're saying is that they're using a 16bit shift 
register to generate a maximal length (65535 states if you don't 
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Reply to
John Fields

Interesting - I hadn't realized that there were other players out there, this is the first time I've come across anything like these. The ADUM5210 does not seem to be available anywhere, though. On Analogs website it's listed as "Product Status:Pre-Release"

Reply to
JW

Could be. I was using the ARUM5200 (25kbps version), IIRC. I only needed 200Hz. ;-) There are several others on the product summary page, without the isolated supply, to 100Mbps. They're under a buck.

Reply to
krw

There's one thing about these devices, they do NOT work down to DC. You need to have a flip of the magnetic polarity at least every few us to reset the detector. Great for DC-balanced protocols like Manchester, but no good for stuff that shuts off the transitions when idle. I tried to use one for a PWM signal in a servo, and it didn't work at all. The manufacturer confirmed that it was not suited for the idle state.

Jon

Reply to
Jon Elson

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we use Silab devices

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Reply to
halong

Bookmarked.

Very cool - it uses RF! Good down to DC and they don't have any weird initialization. Price is a whole lot better as well.

Thanks.

Reply to
JW

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