SPI/Digital or I²C micromodule isolator with dual adjustable 5V regulators

December 12, 2016 // By Graham Prophet
LTM2887 is a 6-channel SPI/Digital or I²C μModule (“micromodule””) isolator with dual rail regulated power that targets low voltage components, including newer DSPs and microprocessors. No external components are required. A single 3.3V or 5V supply powers both sides of the interface through an integrated, isolated DC/DC converter.

Two well-regulated adjustable supply rails (up to 5V) deliver more than 100 mA of load current over the isolation barrier, with up to 62% efficiency. The voltages may be adjusted (using a single external resistor) as low as 0.6V for the auxiliary supply, while the isolated logic supply may be as low as 1.8V for SPI interfaces. Each supply provides a precise current limit adjustment pin and the ability to adjust the voltage using external resistors. The logic supply pin allows interfacing with different logic levels from 1.62V to 5.5V, independent of the main supply.

Coupled inductors and an isolation power transformer provide 2500VRMS of isolation between the input and output logic interface. This device is suitable for systems where the ground loop is broken, allowing for a large common mode voltage range. Communication is uninterrupted for common mode transients greater than 30 kV/μsec.


Linear Technology; www.linear.com/product/LTM2887



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