PCA9508DP,118

The PCA9508 is a CMOS integrated circuit that supports hot-swap with zero offset and provides level shifting between low voltage (down to 0.9 V) and higher voltage (2.7 V to 5.5 V) for I²C-bus or SMBus applications. 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 two buses of 400 pF. Using the PCA9508 enables the system designer to isolate two halves of a bus for both voltage and capacitance, and perform hot-swap and voltage level translation. Furthermore, the dual supply pins can be powered up in any sequence; when any of the supply pins are unpowered, the 5 V tolerant I/O are high-impedance. The hot swap feature allows an I/O card to be inserted into a live backplane without corrupting the data and clock buses. Control circuitry prevents the backplane from being connected to the card until a stop command or bus idle occurs on the backplane without bus contention on the card. Zero offset output voltage allows multiple PCA9508s to be put in series and still maintains an excellent noise margin. PCA9508 has B side and A side bus drivers. The 2.7 V to 5.5 V bus B side drivers behave much like the drivers on the PCA9515A device, while the adjustable voltage bus A side drivers drive more current and incur no static offset voltage. This results in a LOW on the B side translating into a nearly 0 V LOW on the A side. The static offset design of the B side PCA9508 I/O drivers prevents them from being connected to another device that has a rise time accelerator including the PCA9510/A, PCA9511/A, PCA9512/A, PCA9513/A, or PCA9514/A or a static offset voltage including the PCA9507 (B side), PCA9508 (B side), PCA9509 (A side), PCA9515/A, PCA9516A, PCA9517/A (B side), PCA9518, PCA9519 (A side), or P82B96/PCA9600 (Sx/Sy side). The A side of two or more PCA9508s can be connected to

• 2 channel, bidirectional buffer isolates capacitance and allows 400 pF on either side of the device
• Supports offset-free hot-swap with IDLE/STOP detect circuitry
• Voltage level translation from 0.9 V to 5.5 V and from 2.7 V to 5.5 V
• Footprint and functional replacement for PCA9515, PCA9515A, PCA9517 and PCA9517A
• I²C-bus and SMBus compatible
• Active HIGH repeater enable input
• Static level offset on B side
• Open-drain input/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
• A side operating supply voltage range of 0.9 V to 5.5 V
• B side operating supply voltage range of 2.7 V to 5.5 V
• 5 V tolerant I²C-bus and enable pins
• 0 Hz to 400 kHz clock frequency (the maximum system operating frequency may be less than