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LTC4313 - 2-Wire Bus Buffers with High Noise Margin

The LTC®4313 is a hot swappable 2-wire bus buffer that provides bidirectional buffering while maintaining a low offset voltage and high noise margin up to 0.3 • VCC. The high noise margin allows the LTC4313 to be interoperable with devices that drive a high VOL (>0.4V) and allows multiple LTC4313s to be cascaded. The LTC4313-1 and LTC4313-2 support level translation between 3.3V and 5V busses. In addition to these voltages, the LTC4313-3 also supports level translation to 1.5V, 1.8V and 2.5V.

During insertion, the SDA and SCL lines are pre-charged to 1V to minimize bus disturbances. Connection is established between the input and output after ENABLE is asserted high and a stop bit or bus idle condition has been detected on the SDA and SCL pins.

If both data and clock are not simultaneously high at least once in 45ms, the input is disconnected from the output. Up to 16 clock pulses are subsequently generated to free the stuck bus. Rise time accelerators (RTAs) provide pull-up currents on SDA and SCL rising edges to meet rise time specifications in heavily loaded systems. The RTAs are configured as slew limited switches in the LTC4313-1 and 2.5mA current sources in the LTC4313-2. The LTC4313-3 does not have RTAs.

Features Bidirectional Buffer Increases Fanout High Noise Margin with VIL = 0.3•VCC Compatible with Non-Compliant I2C Devices That Drive a High VOL Strong (LTC4313-1) and 2.5mA (LTC4313-2) Rise Time Accelerator Current Level Shift 1.5V, 1.8V, 2.5V, 3.3V and 5V Busses Prevents SDA and SCL Corruption During Live Board Insertion and Removal from Backplane Stuck Bus Disconnect and Recovery Compatible with I2C, I2C Fast Mode and SMBus ±4kV Human Body Model ESD Ruggedness High Impedance SDA, SCL Pins When Unpowered 8-Lead MSOP and 8-Lead (3mm × 3mm) DFN Packages Typical Application

Applications Capacitance Buffers/Bus Extender Live Board Insertion Telecommunications Systems Including ATCA Level Translation PMBus Servers Packaging