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USB µModule Isolator With Power Protects Hubs, Peripheral Ports

USB µModule Isolator With Power Protects Hubs, Peripheral Ports

Combining USB data communications and USB power, the LTM2884 USB µModule (micromodule) isolator guards against ground-to-ground differentials and large common-mode transients. It separates grounds by isolating a pair of USB signal transceivers using internal inductive signal isolation. Thus, the ruggedized device provides 2500-V rms isolation and common-mode transient rejection of less than 30 kV/µs. An integrated, low-EMI, external or bus-powered dc-dc converter that powers the isolated transceiver delivers up to 2.5 W of isolated power for USB peripherals or hub/host controllers. Implementation of an automated bus speed-detection feature allows the LTM2884 to be used in hub/host/bus isolation applications. Integrated downstream-facing pull-down resistors and upstream-facing pull-up resistors are automatically configured to match the speed of the downstream devices, making it possible to monitor and report bus speeds to the host. The ±15-kV transceivers operate at full 12-Mbit/s USB 2.0 speed and low 1.5-Mbit/s speed. A suspend mode monitors for inactivity and reduces VBUS current to less than 2.0 mA. Its dc-dc converter can supply 2.5 W when connected to an external high-voltage supply or 1 W when connected to the USB VBUS supply. The isolator comes in a 15- by 15- by 5-mm, surface-mount BGA package; all integrated circuits and passive components are housed in the µModule package.


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