Global TMW:
Login  |  Register          Free Newsletter Subscription
Subscribe
Email
Print
Reprint
Learn RSS

Digital isolators

Martin Rowe, Senior Technical Editor -- Test & Measurement World, 10/1/2003

Essentially a transformer on a chip, the iCoupler line of digital isolators from Analog Devices (www.analog.com/icoupler) replace optoisolators when you need to isolate digital signals and prevent ground loops.

The iCoupler consists of two separate die—a transmitter and a receiver—packaged into one device. The device's transformer consists of two pairs of coils separated by a 20-µm solid isolation barrier. Planar structures that form primary coils sit vertically above the structures of the secondary coils. Bond wires connect the primary transformer coils to its input die.

Digital isolators use transformers on silicon to replace optoisolators.

The figure shows a block diagram of the device. A Schmitt-trigger inverter ensures that the encoder receives a clean, bounceless edge. The encoder looks for transitions and at each transition creates a pulse that can traverse a tranformer's isolation barrier. Depending on the incoming edge's direction (rising or falling), the encoder sends its output to one of the two primary transformer windings. Upon receiving the signal from the transformer's secondary, the transmitter's decoder can determine the outgoing signal's edge direction, and recreate the original signal edge.

Because the iCoupler uses a transformer to isolate its output, it uses only about 10% of the power that an optoisolator requires to drive its LED. Analog Devices says that the device's bit rate and timing accuracy exceed those of common optoisolators by a factor of 10.

Email
Print
Reprint
Learn RSS

Talkback

We would love your feedback!

Post a comment

» VIEW ALL TALKBACK THREADS

Related Content

Related Content

 

By This Author

Sponsored Links



 
Advertisement
SPONSORED LINKS

More Content

  • Blogs
  • Podcasts

Blogs

  • Rick Nelson
    Taking the Measure

    August 19, 2008
    Nvidia’s GPU quality issues
    What should Nvidia do about suspect graphics processing units, which might fail because of a potenti...
    More
  • Rick Nelson
    Taking the Measure

    August 14, 2008
    Diamond advances amid merger process
    Credence and LTX executives remain mum on long-term plans to rationalize product lines in light of t...
    More
  • » VIEW ALL BLOGS RSS

Podcasts

Advertisements





NEWSLETTERS
Click on a title below to learn more.

Test Industry News (3 Times Per Month)
Machine-Vision & Inspection (Monthly)
Communications Test (Monthly)
Design, Test & Yield (Monthly)
Automotive, Aerospace & Defense (Monthly)
Instrumentation (Monthly)
Resource Center E-Alert (Monthly)
©2008 Reed Business Information, a division of Reed Elsevier Inc. All rights reserved.
Use of this Web site is subject to its Terms of Use | Privacy Policy
Please visit these other Reed Business sites