Isolation amplifiers?? (for oscilloscope)

[nctnico]

I'm looking into getting some isolated channels on an oscilloscope. For example to look at the gate drive signal of a high side mosfet. I know there are differential probes but these also attenuate the signal. What I would want is the ability to measure a few volts riding on top of a couple of hundreds volts.

So far I have found an isolation amplifier made by Siglent but that only goes to 1MHz. Are there any other options out there?

[MagicSmoker]

Aside from an oscilloscope with properly isolated inputs, the only reasonable option to probe line-side signals in a SMPS is a differential probe. The usual differential probe with 25MHz bandwidth will faithfully reproduce "square" waves with a ~15ns risetime which ought to be more than sufficient.

That said, I use two different scopes with truly isolated inputs for most of my work on switchmode power circuits - an ancient, but much beloved Tek THS720 and a newer but not as much loved AEMC OX7104. I also have a couple of B&K Precision 25MHz differential probes but they spend most of the time draining AA batteries (but do work well when used).

[tautech]

Correct, however the Siglent ISFE is a 2 channel accesory that offers good isolation and lower DUT loadings than many Differential probes. USB powered.
http://www.siglentamerica.com/prodcut-fjxx.aspx?fjid=404&id=25&tid=1&T=2

You should be aware it has a 200:1 attenuation and FW to match this to enable accurate OSD in Siglent DSO's is being rolled out in each FW update.
I've had a lot to do with this FW  and it was discussed at length when I was at the factory some months back.

[0xdeadbeef]

Testec offers quite a few differential probes. They are rebranded by Tektronix, Agilent/Keysight, Hameg, Lecroy, Yokogawa etc.
http://www.testec.de/251.0.html?L=1

My personal favorite would be this one:
http://www.reichelt.de/Tastkoepfe-und-Zubehoer/TT-SI-9101/3/index.html?ACTION=3&GROUPID=5903&ARTICLE=132890&OFFSET=16&

100MHz and switchable 10:1 or 100:1 ratio. Unfortunately a bit expensive. I hope to get find one on ebay for 300€ or so one day.

[nctnico]

IMHO one of the problems with differential probes is the banana plugs & leads. That won't work for signals over a few MHz. I would like something I can connect a somewhat standard oscilloscope probe to (with touch safe BNC locking mechanism) and attach it somewhere in a circuit.

[0xdeadbeef]

Something like this?
http://www.voelkner.de/products/96796/Chauvin-Arnoux-Mtx-1032-B-Differenzsonde.html

[tautech]

IMHO one of the problems with differential probes is the banana plugs & leads. That won't work for signals over a few MHz. I would like something I can connect a somewhat standard oscilloscope probe to (with touch safe BNC locking mechanism) and attach it somewhere in a circuit.

This you can do with Siglents ISFE.
I attach an email that was sent to Siglent but has an overview of ISFE useage.

[nctnico]

I already looked at the ISFE but the bandwidth is only 1MHz and the 200:1 attenuation ratio limits the use enormously.

[The Electrician]

a newer but not as much loved AEMC OX7104.

Slightly OT, but what don't you like about the AEMC OX7104?