PCA9518

PCA9518 Expandable 5-channel I2C-bus hub Rev. 05 — 2 December 2008 Product data sheet 1. General description The PCA9518 is a BiCMOS integrated circuit intended for application in I2C-bus and SMBus systems. While retaining all the operating modes and features of the I2C-bus system, it permits extension of the I2C-bus by buffering both the data (SDA) and the clock (SCL) lines, thus enabling virtually an unlimited number of buses of 400 pF. The I2C-bus capacitance limit of 400 pF restricts the number of devices and bus length. Using the PCA9518 enables the system designer to divide the bus into an unlimited number of segments off of a hub where any segment to segment transition sees only one repeater delay and is multiple master capable on each segment. Using multiple PCA9518 parts, any width hub (in multiples of five)1 can be implemented using the expansion pins. The PCA9518 is a wider voltage range (2.3 V to 3.6 V) version of the PCA9518 and also improves partial power-down performance, keeping I2C-bus I/O pins in high-impedance state when VDD is below 2.0 V. A PCA9518 cluster cannot be put in series with a PCA9515/16 or with another PCA9518 cluster. Multiple PCA9518 devices can be grouped with other PCA9518 devices into any size cluster thanks to the EXPxxxn pins that allow the I2C-bus signals to be sent/received from/to one PCA9518 to/from another PCA9518 within the cluster. Since there is no direction pin, slightly different ‘legal’ low voltage levels are used to avoid lo...