Bi-directional buffer supports ‘always on’ networks

Automatic connection and isolation for serial buses in hot-swap environments is provided by the PI6ULS5V9511A I2C/SMBus buffer, introduced by Diodes.

It has been developed to enable hot-swappable line-cards in ‘always-on’ networks, such as rack-based systems to enable critical systems such as web servers, networks, and telecommunications applications using standards such PCI/cPCI, VME, and AdvancedTCA. These critical systems need to deliver upwards of 99.999% availability, where prolonged maintenance and unplanned downtime is unacceptable. Hot-swapping, or adding and removing linecards without removing power, is a technique used to keep these systems running, but today’s sensitive, high-speed serial communication buses are not designed to facilitate hot-swapping.

The PI6ULS5V9511A provides the protection needed to hot-swap cards that employ serial buses such as I2C and SMBus. It provides a bi-directional buffer between the card’s SDA and SCL signals and the system’s live buses. Integrated control circuits detect bus activity, allowing the PI6ULS5V9511A to maintain electrical isolation between the live system and the line-card until it identifies a stop command or the bus is idle, at which point it switches in the signals without causing bus contention or data disruption, explains Diodes. This eliminates the potential for bus corruption during card insertion and removal.

Rise-time accelerators meet rise-time requirements on all data pins, while pre-charge technology minimises the current required to overcome the parasitic capacitance present on the data pins. The PI6ULS5V9511A provides drive capabilities making it also an effective buffer for increasing the fan-out of an I2C/SMBus port, claims Diodes.

The PI6ULS5V9511A features an active-high ‘ready’ pin which indicates to the system when connection is established. There is also an active-high ‘enable’ pin that can be used to isolate the two sides of the bi-directional buffer. ESD protection exceeds 4000V HBM, as specified in the JESD22-A114 JEDEC standard.

The PI6ULS5V9511A is available in three package options for applications where there are strict space restrictions. They are the SO-8(W), MSOP-8(U), and the smaller UDFN-8(ZW) packages.