Demonstration circuit 2686A is a 1.3A 8-switch matrix LED dimmer system with an I²C to CAN-physical transceiver featuring the LT3967 and LT3960. This demonstration circuit connects directly to a LED string and LED driver demonstration circuit to allow for independent dimming control of up to 8 channels of LEDs. A Linduino^® One demonstration circuit is used to interface with the board and can connect in one of two different ways:

1. Connect directly to a Linduino One demonstration circuit with a QuikEval^™ ribbon cable.
2. Connect using the LT3960 break-off board to connect to the I²C master device, but pass data over two twisted pair lines to the LT3960 on the main PCB.

The LT3967 matrix dimmer features 8 individually con-trolled 1.3A rated floating NMOS switch channels and can support up to 56V of LEDs per device. The channels of the LT3967 can be configured for series connections, or non-series connections. Additional DC2686A demo circuits can be connected in series for higher number of LEDs, or in parallel to allow for higher current operation. Resistors are used to configure both the I²C slave address as well as the default start-up state. The default configuration for DC2686A sets the I²C address as 0000 with all LEDs off. See the LT3967 data sheet for details.

The LT3960 I²C to CAN-Physical transceiver is used to send and receive I²C data through harsh or noisy environments at up to 400kb/s using the CAN-Physical layer for differential signaling over twisted pair connections. Both SDA and SCL data lines are converted to differential signals and are shared between devices connected to the bus. This allows for physical separation of the I²C source with the LT3960 transceiver board and the LT3967 main PCB along with the LED driver.

This demo circuit is designed to be easily configured and interfaced with a compatible low output capacitance LED driver and LED string. It can easily be directly attached to a buck LED driver or a floating buck-mode LED driver. More sophisticated setups with series matrix dimmers for higher number of LEDs such as 12 or 16 is possible. Please consult factory applications for details or look for more details on analog.com.

The LT3967 and LT3960 data sheets give complete description of the parts, their operation and applications information. The data sheets must be read in conjunction with the demo manual for demonstration circuit DC2686A. The LT3967EFE is assembled in a thermally enhanced 28-lead TSSOP package. The LT3960EMSE is assembled in a 10-lead MSOP package.