PCA9548APW

Product Summary

The PCA9548APW is an 8-channel I2C-bus switch with reset. The SCL/SDA upstream pair fans out to eight downstream pairs, or channels. Any individual SCx/SDx channel or combination of channels can be selected, determined by the contents of the programmable control register. An active LOW reset input allows the PCA9548APW to recover from a situation where one of the downstream I2C-buses is stuck in a LOW state. Pulling the RESET pin LOW resets the I2C-bus state machine and causes all the channels to be deselected as does the internal Power-on reset function. The pass gates of the switches are constructed such that the VDD pin can be used to limit the maximum high voltage which will be passed by the PCA9548APW. This allows the use of different bus voltages on each pair, so that 1.8 V or 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.

Parametrics

PCA9548APW absolute maximum ratings: (1)VIL LOW-level input voltage: -0.5, +0.3VDD V; (2)VIH HIGH-level input voltage: 0.7VDD, 6 V; (3)IOL LOW-level output current VOL = 0.4V: 3mA, VOL = 0.6 V: 6mA; (4)IIL LOW-level input current VI = VSS: -1, +1 μA; (5)IIH HIGH-level input current VI = VDD: -1, +1 μA; (6)Ci input capacitance VI = VSS: 15, 21 pF.

Features

PCA9548APW features: (1)1－of－8 bidirectional translating switches; (2)I2C－bus interface logic; compatible with SMBus standards; (3)Active LOW reset input; (4)3 address pins allowing up to 8 devices on the I2C－bus; (5)Channel selection via I2C－bus, in any combination; (6)Power－up with all switch channels deselected; (7)Low Ron switches; (8)Allows voltage level translation between 1.8 V, 2.5 V, 3.3 V and 5 V buses; (9)No glitch on power－up; (10)Supports hot insertion; (11)Low standby current; (12)Operating power supply voltage range of 2.3 V to 5.5 V; (13)5 V tolerant inputs; (14)0 Hz to 400 kHz clock frequency.

Diagrams