USB µModule transceiver provides 7.5 kV isolation

November 23, 2016 // By Graham Prophet
One of series of devices introduced to provide isolation to signal paths, LTM2894 is a USB µModule (micromodule) reinforced isolator that guards against ground-to-ground voltage differentials and large common mode transients.

A rugged interface and internal isolation suits the LTM2894 for systems implementing USB in harsh industrial or medical environments where protection from high voltages is required: it follows Linear Technology’s introduction of the related LTM2893 , for fast SPI bus isolation. The LTM2894 separates grounds by isolating a pair of USB signal transceivers using internal signal isolation, providing 7500 VRMS isolation plus common mode transient rejection of greater than 50 kV/µsec. Able to withstand up to 1000VRMS continuously, the LTM2894 also provides 17.4 mm of creepage, a separation distance that allows medical equipment, according to IEC 60601-1, to operate from mains voltages greater than 250 VRMS while satisfying two means of patient protection (MOPP).


The LTM2894 is suitable for use in a wide variety of USB hub, host and bus isolation applications. The ±20 kV ESD-protected transceivers operate at USB 2.0 full speed (12 Mbps) and low speed (1.5 Mbps), while a suspend mode monitors for inactivity and reduces VBUS current to less than 2.0 mA. Integrated downstream facing pull-down resistors and upstream facing pull-up resistors are automatically configured to match the speed of the downstream device, enabling the LTM2894 to monitor and report bus speeds to the host. The LTM2894 requires no external components and is a complete µModule solution for isolated USB communications.


The LTM2894 is available in a 22 x 6.25 mm surface mount BGA package; all integrated circuits and passive components are housed in this RoHS-compliant µModule package. The LTM2894 is available in commercial, industrial and automotive versions, supporting operating temperature ranges from 0°C to 70°C, –40°C to 85°C and –40°C to 125°C, respectively. Pricing starts at $12.20 (1,000).


Linear Technology;