EMI Absorption Sheet and Tape from Molex - Page 1
Forum section: electronics / projects

author: juanfermed
author_rank: Regular Contributor
timestamp: April 15, 2014, 10:04:06 pm
content: Hi everyone, I just wanted to ask your opinion about this new (at least I havent heard of it before) product from Molex: Molex HOZOX™ EMI Absorption Sheet & Tape.According to the announcement at mouser's webpage "While only 0.1mm thick, these flexible sheets suppress most unwanted electromagnetic interference (EMI) while meeting government EMC regulations worldwide. The unique dual-layer structure of the HOZOX allows the sheeting to efficiently absorb both megahertz and gigahertz electromagnetic energy, providing a wide range of EMI protection for a variety of applications."What are your thoughts on this? I not an electronics expert but, doesn't this sound like those audiofools "superquality noise supressive AC power cords"? They come from Molex, a big name, but thoses sheets are a little crazy.You can read more here:http://www.mouser.com/publicrelations_molex_hozox_2014final/http://www.mouser.com/new/molex/molex-hozox-emi/?cm_mmc=PressRelease-PR-_-Molex-_-HOZOX-_-2014-04-15Thanks for your comments.

author: kizzap
author_rank: Unknown
timestamp: April 15, 2014, 11:43:13 pm
content: well considering EMI is classed as being of the range of Hz to 30MHz, I feel that it is going to be more ideal for RFI?

author: ejeffrey
author_rank: Super Contributor
timestamp: April 15, 2014, 11:52:05 pm
content: Quote from: juanfermed on April 15, 2014, 10:04:06 pmThere are tons of products like this, and they do real things. EMC compliance and noise are huge issues in high speed electronics. The difference between this sort of stuff and audiophile garbage is that the production and use of these products is driven by measurements, while audiophiles deny the relevance of the measurements that show that their snake-oil nonsense makes no difference.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 16, 2014, 12:04:06 am
content: Neato. I've seen permeable flex sheets and stuff before, but usually with lower mu, only useful into the gigs. It's not obvious, from the data they provide, how much attenuation you'd get at <100MHz in a given situation; despite the moderate permeability and permittivity, the thickness is quite low, so it's quite easy for stuff to get through. As far as near fields go, it probably works better on higher impedance (electrostatic) signals, due to the conductive layer and higher permittivity, and not so well on low impedance (electromagnetic) signals, which will tend to penetrate, or even saturate the material (if we're talking power conversion level fields). So regarding applications, you'd probably be looking for this sort of stuff around sensitive analog, digital, wideband and RF circuitry, and maybe to help take a few dB off a not-quite-compliant product (of any sort: power, computing, mobile, RF, etc.). It's probably quite handy inside molded plastic cases, which you'd have to weigh against other coatings or options (conductive paint, metallization).If you need that sort of shielding for *powerful* magnetic fields, ferrite slabs are the way to go. FYI, you can get plates used for planar cores, and plates or disks used for spot shielding (I think the largest and thinnest such product I've seen is 2 x 2 x 0.1" from.. Laird?).I've had situations where -- the EMI isn't even the biggest concern, the cabinet itself is actually getting too hot! Fields this intense can't even be stopped by solid copper shielding: it still gets too hot. Let alone EMI gasketing or spring stock, which get *really* hot. But, put some ferrite around the offending coil and it stays ice cold.Tim

author: georges80
author_rank: Frequent Contributor
timestamp: April 16, 2014, 01:00:10 am
content: Yeah, the stuff is real and not cheap either...I have a sample from a recent trade show, the stuff works. This is the company that provided me a sample and the 'type' of material:http://intermark-usa.com/products/emc/emi-absorbers/cheers,george.

author: theatrus
author_rank: Frequent Contributor
timestamp: April 16, 2014, 04:28:10 pm
content: This type of material is generally expensive, but depending on how many units you're making cheaper than tooling new shields or cases when EMC is an issue. I assume these sheets could be fed through an ordinary diecutter in the end.