The ADUM4160BRIZ is an USB port Digital Isolator, based on Analogue Devices, Inc., iCoupler? technology. Combining high speed CMOS and monolithic air core transformer technology, this isolation component provides an outstanding performance characteristics and are easily integrated with low and full speed USB-compatible peripheral devices. Many microcontrollers implement USB so that it presents only the D+ and D- lines to external pins. This is desirable in many cases because it minimizes external components and simplifies the design, however this presents particular challenges when isolation is required. USB lines must automatically switch between actively driving D+/D-, receiving data and allowing external resistors to set the idle state of the bus. This provides mechanisms for detecting the direction of data flow and control over the state of the output buffers. Data direction is determined on a packet-by-packet basis.