1 Features
1• Expandable Five-Channel Bidirectional Buffer
• 400-kHz Fast I2C Bus
• Operating VCC Range of 3 V to 3.6 V
• 5-V Tolerant I2C and Enable Input Pins to Support
Mixed-Mode Signal Operation
• Active-High Individual Repeater Enable Inputs
• Open-Drain Input/Outputs
• Lockup-Free Operation
• Supports Multiple Masters
• Powered-Off High-Impedance I2C Pins
• I2C Bus and SMBus Compatible
• Latchup Performance Exceeds 100 mA Per JESD
78
• ESD Protection Exceeds JESD 22
– 2000-V Human-Body Model (A114-A)
– 200-V Machine Model (A115-A)
– 1000-V Charged-Device Model (C101)

2 Description
The PCA9518 is an expandable five-channel
bidirectional buffer for I2 C and SMBus applications. The I2C protocol requires a maximum bus
capacitance of 400 pF, which is derived from the
number of devices on the I2C bus and the bus length.
The PCA9518 overcomes this restriction by
separating and buffering the I2C data (SDA) and clock (SCL) lines into multiple groups of 400-pF
segments. Any segment-to-segment transition sees
only one repeater delay. Each PCA9518 can
communicate with other PCA9518 hubs through a 4- wire inter-hub expansion bus. Using multiple
PCA9518 parts, any width hub (in multiples of five)
can be implemented using the expansion pins, with
only one repeater delay and no functional
degradation of the system performance.
The PCA9518 does not support clock stretching
across the repeater.