Isolated Transceivers

Linear Technology’s Isolated Transceivers provide robust galvanic isolation for various digital serial communication interfaces and devices, including SPI, I2C, RS485/RS422, RS232, USB, CAN, data converters and switches.  Isolation barriers are implemented using either inexpensive Ethernet transformers, coupling capacitors or embedded inductors.  All devices are simple to configure and feature very low EMI susceptibility and emissions, as well as high noise immunity, to preserve signal integrity.

Linear Technology’s Isolator µModule Technology (found in the LTM28xx isolator series and LTM9100) is a new development platform that allows Linear to reliably integrate inductive/magnetic isolation, discrete components, ICs and power onto a single substrate PCB.  This high level of integration results in products that require no external components; all resistors, capacitors, inductors and ICs are onboard.  Any application from signaling to sampling can be supported by the platform, delivering isolation to even non-traditional applications.  High power levels (up to 2.5W), supported by low ripple regulation, a cored power transformer that reduces radiated emissions, and better-than-average efficiency up to 65%, are available to the application. Not only is the device self-powered, but it also provides external isolated power for other neighboring functions. To achieve isolation of up to 7500VRMS, the technology uses coupled signal inductors embedded in our µModule substrate. This technique ensures consistent ruggedness and reliability.  This platform is certified by safety houses, including UL, CSA and IEC to guarantee the isolation barrier’s effectiveness.

For robust isolated communication across long cable lengths, Linear Technology’s isoSPI™ interface translates bidirectional SPI across an isolated barrier of up to 100 meters using twisted pair wire and a simple pulse transformer. Designed for high voltage and high noise systems, isoSPI provides safe and robust information transfer up to 1MHz.

For bidirectional I2C communication predominant in large multi-master systems, the LTC4310 isolates two busses using either coupling capacitors for low voltage isolation or a transformer for high voltage isolation.  Other I2C specific features include hot-swappable SDA and SCL lines, voltage level translation, rise time acceleration to help meet standard requirements, and stuck bus disconnect and recovery circuitry to promote autonomous operation.

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