Digital isolators reach 2 Mbps, pack in as many as four channels
By Margery Conner, Technical Editor -- EDN, July 17, 2008
Using optocouplers is a common, inexpensive method of signal isolation, but your application may be unable to tolerate optocouplers’ tendency to degrade with age and temperature. Targeting that problem, NVE has introduced the IsoLoop IL500 series of nonoptical digital isolators that operate as fast as 2 Mbps. The parts feature a patented, controllable refresh clock to ensure I/O synchronization within 9 μsec; some models in the series allow the use of an external synchronization clock. Maximum propagation delay is 25 nsec, and pulse-width distortion is 10 nsec.
The series is available in one-, two-, three-, and four-channel models; the one- and two-channel models are available in either SOIC packages or eight-pin MSOPs. The three- and four-channel models are available in 0.15- or 0.3-in.-wide, 16-pin SOIC packages. All NVE products are available in ROHS (restriction-of-hazardous-substances)-directive-compliant, lead-free versions. The isolators operate over a supply-voltage range of 3 to 5.5V and temperature range of −40 to +85°C. Typical transient immunity is 30 kV/μsec. The parts are UL (Underwriters Laboratories) 1577-approved, and IEC (International Electrotechnical Commission) 61010-2001 approval is pending. Prices start at 53 cents (1000) per channel.
