PCA9544A

• 1-of-4 Bidirectional translating switches
• I²C Bus and SMBus compatible
• Four active-low interrupt inputs
• Active-low interrupt output
• Three address pins, allowing up to eight devices on the I²C Bus
• Channel selection via I²C Bus
• Power up with all switch channels deselected
• Low R_ON switches
• Allows voltage-level translation between 1.8-V, 2.5-V, 3.3-V, and 5-V Buses
• No glitch on power up
• Supports hot insertion
• Low standby current
• Operating power-supply voltage range of 2.3 V to 5.5 V
• 5.5-V Tolerant inputs
• 0 to 400-kHz Clock frequency
• Latch-up 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)

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The PCA9544A is a 4-channel, bidirectional translating multiplexer controlled via the I²C bus. The SCL/SDA upstream pair fans out to four downstream pairs, or channels. One SCL/SDA pair can be selected at a time, and this is determined by the contents of the programmable control register. Four interrupt inputs (INT3–INT0), one for each of the downstream pairs, are provided. One interrupt output (INT) acts as an AND of the four interrupt inputs.

A power-on reset function puts the registers in their default state and initializes the I²C state machine, with no channel selected.

The pass gates of the switches are constructed such that the V_CC pin can be used to limit the maximum high voltage, which will be passed by the PCA9544A. This allows the use of different bus voltages on each pair, so that 1.8-V, 2.5-V, or 3.3-V parts can communicate with 5-V parts, without any additional protection. External pull-up resistors pull the bus up to the desired voltage level for each channel. All I/O pins are 5-V tolerant.