Friday, January 14, 2011

Hot swappable 2-channel 2-wire multiplexer with bus buffers

Linear Technology’s LTC4312 is a hot-swappable 2-channel 2-wire bus multiplexer that allows one upstream bus to connect to any combination of downstream busses or channels. An individual enable pin controls each connection.

The LTC4312 provides bidirectional buffering, keeping the upstream bus capacitance isolated from the downstream bus capacitances. The high noise margin allows the LTC4312 to be interoperable with I2C devices that drive a high VOL (> 0.4V).

The LTC4312 supports level translation between 1.5V, 1.8V, 2.5V, 3.3V and 5V busses. The hot-swappable nature of the LTC4312 allows I/O card insertion into, and removal from, a live backplane without corruption of the data and clock busses.

If both data and clock are not simultaneously high at least once in 45ms and DISCEN is high, a FAULT signal is generated indicating a stuck bus low condition, the input is disconnected from each enabled output channel and up to 16 clocks are generated on the enabled downstream busses.

A three state ACC pin enables input and output side rise time accelerators of varying strengths and sets the VIL, RISING voltage.


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