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Analog Devices have released to market the LT3960 device, a robust high speed transceiver that extends a single-master I²C bus through harsh or noisy environments at up to 400kbps using the CAN-physical layer.

The LT3960 high-speed transceiver creates the functional equivalent of a single-master I²C bus in the CAN physical layer and is powered from a single wide-ranging input voltage. Using two integrated CAN transceivers, the LT3960 creates a differential proxy for each of the single-ended I²C clock and data signals which is capable of traversing harsh or noisy environments across two twisted pairs.
Each transceiver consists of a transmitter and receiver, capable of quickly converting a single-ended I²C dominant signal into a differential dominant signal, and vice versa. The transmitter is a current-regulated differential driver that generates a differential voltage between the CANxH and CANxL pins determined by drive current and the equivalent resistive load on the CANx bus. Common mode voltage of the CANx bus is regulated by the transmitter when driving dominant as described in the applications section. The receiver is a CAN compatible differential receiver with a wide common-mode range of ±25V or ±36V, depending on VCC voltage.

Simple yet elegant in operation, one LT3960 device is installed near the I²C master, creating from SCL and SDA data lines equivalent differential buses (I²CAN) on two twisted pairs. At the other end of the twisted pairs, a second LT3960 recreates the I²C bus locally for one or more slave I²C devices. The SDA and SCL data lines from the LT3960 are converted to differential signals and are shared between devices connected to the bus, this allows for the physical separation of the I²C source and I²C receiver. The LT3960 devices transmit the clock signal in only one direction, from master to slave. Bidirectional communication of the data signal is always permitted.

LT3960 Application Circuit

The LT3960 can also be used as a I²C to CAN-Physical Transceiver in Automotive Audio Bus (A2B) Communications, application note EE-431 provides technical notes on how to achieve this, see link to application note under the data section of this page.

The LT3960 features an integrated LDO which regulates an input from the VIN pin between 4V and 60V to 3.3V on the VCC pin from which the transceivers and bus lines are powered. Alternatively, the LT3960 can by powered from a supply voltage of 3.3V or 5V on VIN, bypassing the LDO by shorting VCC to VIN.

LT3960 Block Diagram

LT3960 Performance Graph
Receiving I²C Traffic Across ±25V Common-Mode Differential

The LT3960 is housed in a compact 10-lead MSOP package and has a choice of operating temperature ranges, -40°C to 125°C (LT3960E) or -40°C to 150°C (LT3960J). Automotive grade parts are available with controlled manufacturing to support the quality and reliability requirements of automotive applications.

Evaluation Board

Analog Devices provide developers support via the EVAL-LT3960-AZ evaluation board which features the LT3960 device in a 10-lead plastic MSOP package. The EVAL-LT3960-AZ evaluation board consists of two ICs configured in the master and slave mode using selectable jumpers, JP1 and JP3. The twin board is designed to be easily snapped apart at the centre, separating two circuitries so they can be used at either end of the twisted pair cable.

The LT3960 high speed I²C to CAN-Physical Transceiver is suitable for a range of applications including Industrial Networking, Automotive Networking and Remote Sensors.

Anglia are offering customers a FREE evaluation board and samples of the LT3960 high speed I²C to CAN-Physical Transceiver from Analog Devices, please fill in the form below to register your interest now.