Bidirectional buffer provides automatic connection and isolation for serial busses

Diodes Incorporated offers the PI6ULS5V9511A I2C/SMBus buffer which allows hot-swappable line-cards in ‘always-on’ networks, and is offered in a variety of packages. Rack-based systems allow networks, web servers, and telecommunication applications using standards such as PCI/cPCI, VME, and AdvancedTCA. These critical systems must deliver upwards of 99.999% availability, which makes extended maintenance and unplanned downtime unacceptable. Hot-swapping, adding and removing line-cards without removing power, is universally employed to keep the systems running; but, today’s sensitive, high-speed serial communication busses were not intended to facilitate hot-swapping. To meet this need, the device provides the protection required to hot-swap cards that use serial busses such as I2C and SMBus. It offers an effective bidirectional buffer between the card’s SDA and SCL signals and the system’s live busses. Integrated control circuits identify bus activity, enabling the device to preserve electrical isolation between the live system and the line-card until it recognises a stop command or the bus is idle, at which point it switches in the signals without causing bus contention or data disruption. This removes the potential for bus corruption during card insertion and removal.