While one wouldn't normally believe that USB devices can be affected by such power-related problems as noise, spikes and errors from ground loops, that's unfortunately the case, and exactly for this reason Acromag has developed the USB Isolator, a compact, industrial-rated device that protects against over-voltage conditions caused by electrical surges and transient voltage spikes.

Designed to work with USB 2.0 and USB 1.1 interfaces, this device will also help eliminate ground loop errors and will minimize conducted noise from static discharge, magnetic fields, and radio frequency interference.

The isolator is inserted in-line with the USB connection and operates transparent to the devices with no software drivers required, receiving its power from USB and isolates that power to the connected device.

A green power LED indicates that power is being received and will blink if the connected device is trying to draw more than 120mA.

Default communication is USB Full Speed (12Mbps) but can alternately be set for Low Speed (1.5Mbps) via an internal jumper.

The reset button enables re-initialization of a connected device without breaking the cable connection, while the high-retention USB A and USB B sockets increase connection integrity under shock and vibration.

Moreover, electrical isolation of up to 1500V AC / 2100V DC separates the USB host from the USB peripheral, while the built-in surge/transient suppression up to 8kV protects all ports.

Common mode filtering is also applied on all data lines and the output short circuit protection adds further safety and includes an auto-retry function.

Typical applications involve process control devices, automation equipment, test and measurement systems, and medical instrumentation.

The $99 isolator is less than 1 x 2.5 x 2 inches and includes a USB host cable, thus making it a fairly affordable solution for the intended range of applications.