Why Choose a Silicon Labs Digital Isolator instead of an Optocoupler?

Why Use Silicon Labs Isolation Products?

Silicon Labs' CMOS digital isolator products enable lower cost, smaller size, higher performance, lower power and more reliable isolated circuits than competing optocoupler solutions. The Si86xx, Si87xx and Si88xx families of one to six-channel bi- and unidirectional digital isolators support isolation voltage ratings up to 5 kV. Devices from all ranges and evaluation tools are available from RS.

Silicon Labs isolator products are used by a wide range of customers and applications from Industrial automation, transportation systems, home entertainment electronics, medical systems and more.

Unlike optocouplers, these robust devices have none of the intrinsic wear-out mechanisms found in optocouplers and remain parametrically stable in operating environments over the temperature range of -40 °C to +125 °C. Silicon Labs isolation products emit virtually no EMI and are highly resistant to external fields. Their digital isolators provide safety isolation, level-shifting and ground noise reduction while enabling small form factor systems. 

Si88xx Digital Isolators with Integrated dc-dc Converter

The new Si88xx family of products combine high-speed digital isolators with an isolated power supply. This integrated product for signal and power isolation provides a complete isolation solution to designers. The Si88xx has up to four high-speed digital isolation channels integrated with a modified fly-back topology based dc-dc converter. The dc-dc converter works in conjunction with an external transformer to provide up to 2W of isolated power that can be used to supply the secondary side of the Si88xx as well as other circuits on the isolated side. The converter provides a high efficiency of 78%. It includes built-in secondary sensing and feedback through the isolation barrier back to the controller to achieve excellent line and load regulation for system stability. The converter also includes safety features like soft start, thermal detection and cycle by cycle current limiting. See below video for more info.

Features

• dc-dc converter
  • Integrated dc-dc converter, up to 2W power
  • Fully-integrated, secondary sensing, feedback controlled converter with dithering for low EMI
  • dc-dc converter efficiency of 78%
  • dc-dc shutdown, programmable frequency control and soft start
  • Conversion from 3/5 V to isolated 3/5 V, 24 V to isolated 3/5 V supported
• Digital isolation
  • Precise timing on high speed 100 Mbps digital isolators, 23 ns typ prop delay
  • Transient immunity of 100 kV/µs typical
  • High electromagnetic immunity and ultra-low emissions
  • Isolation of up to 5000 Vrms
  • Highly-reliable: 100 year lifetime
  • RoHS compliant packages: SOIC-20 wide body
  • AEC-Q100 qualified
  • Wide temperature range: -40 to +125 °C

Applications

• Industrial automation systems
• Hybrid electric and electric vehicles
• Isolated power supplies
• Inverters
• Data acquisition
• Motor Control
• PLCs, distributed control systems

For more details and technical documentation about the range of Digital Isolators visit www.silabs.com/products/power/isolators/Pages/default.aspx

To test the performance for yourself RS are stocking the Si882xx Isolator Evaluation Board