General description
The PCA9509 is a level translating I2C-bus/SMBus repeater that enables processor low voltage 2-wire serial bus to interface with standard I2C-bus or SMBus I/O. While retaining all the operating modes and features of the I2C-bus system during the level shifts, it also permits extension of the I2C-bus by providing bidirectional buffering for both the data (SDA) and the clock (SCL) lines, thus enabling the I2C-bus or SMBus maximum capacitance of 400 pF on the higher voltage side. Port A allows a voltage range from 1.35 V to VCC(B) - 1.0 V and requires no external pull-up resistors due to the internal current source. Port B allows a voltage range from 3.0 V to 5.5 V and is overvoltage tolerant. Both port A and port B SDA and SCL pins are high-impedance when the PCA9509 is unpowered.

Features and benefits
■ Bidirectional buffer isolates capacitance
   and allows 400 pF on port B of the device
■ Voltage level translation from port A
   (1.35 V to VCC(B) - 1.0 V) to port B (3.0 V to 5.5 V)
■ Requires no external pull-up resistors on lower voltage port A
■ Active HIGH repeater enable input
■ Open-drain inputs/outputs
■ Lock-up free operation
■ Supports arbitration and clock stretching across the repeater
■ Accommodates Standard-mode and Fast-mode I2C-bus devices and multiple masters
■ Powered-off high-impedance I2C-bus pins
■ Operating supply voltage range of 1.35 V to
   VCC(B) - 1.0 V on port A, 3.0 V to 5.5 V on port B
■ 5 V tolerant port B SCL, SDA and enable pins
■ 0 Hz to 400 kHz clock frequency
   Remark: The maximum system operating frequency may be less than 400 kHz
   because of the delays added by the repeater.
■ ESD protection exceeds 2000 V HBM per JESD22-A114 and 1000 V CDM per
   JESD22-C101
■ Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA
■ Packages offered: TSSOP8, SO8, XQFN8