Data and power isolation in critical USB environments

June 01, 2015 // By Graham Prophet
Murata’s NMUSB202MC is a surface mount, powered data isolator module that provides dual port USB data and power isolation from a single upstream port with full power (USB 2, 500 mA) available from each port. Used with a host controller a single module counts as two USB hubs for cascaded applications with the level of safety isolation additionally providing effective breaking of ground loops and immunity to EMI in harsh environments.

The module is aimed at industrial control applications where USB is becoming increasingly common for communications with sensors. It is also suitable for use in medical environments with the increasing use of USB for low cost sensing and communication where isolation is necessary for safety and noise immunity.

‘Full’ USB speed operation (12 Mbps) is supported, limited by the data isolation chipset. The module is also able to switch automatically between low (1.5Mbps) and full speed operation, as the application requires.

The module’s full compliance with USB 2.0 specification enables trouble free, full ‘plug and play’ operation and its surface mount package for placement on the host motherboard enables the USB isolation function with a single SMT component.

Full power, 5V/0.5A, meeting the USB bus standard is available from each downstream port and users may power any USB compatible device from the NMUSB module. The ports are short circuit and overload protected. The source power of 5V can be provided by an external adapter or system voltage rail.

The NMUSB202MC’s reinforced safety isolation barrier meets the requirements of 250VAC systems in IT and medical environments for operator protection, allowing use of the product to provide safety isolation in USB connections in critical applications. Safety agency recognition is pending. A full industrial temperature range of -40 to +85C is accommodated.

Murata Electronics; www.murata.com