2-CHANNEL I2C BUS SWITCH WITH INTERRUPT LOGIC AND RESET
DESCRIPTION
The UTC UCA9543 is a dual bidirectional translating switch
controlled by the I2C bus. The SCL/SDA upstream pair fans out to
two downstream pairs, or channels. Either individual SCn/SDn
channel or both channels can be selected, determined by the
contents of the programmable control register. Two interrupt inputs
(INT1 - INT0), one for each of the downstream pairs, are provided.
One interrupt output (INT) acts as an AND of the two interrupt
inputs.
An active-low reset (RESET) input allows the UTC UCA9543
to recover from a situation where one of the downstream I2C buses
is stuck in a low state. Pulling RESET
low resets the I2C state
machine and causes both of the channels to be deselected, as
does the internal power-on reset function.
The pass gates of the switches are constructed such that the
VCC pin can be used to limit the maximum high voltage, which will
be passed by the UTC UCA9543. This allows the use of different
bus voltages on each pair, so that 1.8V, 2.5V, or 3.3V parts can
communicate with 5V 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 5.5V tolerant.
FEATURES
* 1-of-2 Bidirectional Translating Switches
* I2C Bus and SMBus Compatible
* Two Active-Low Interrupt Inputs
* Active-Low Interrupt Output
* Active-Low Reset Input
* Two Address Pins Allowing up to Four UTC UCA9543 Devices on the I2C Bus
* Channel Selection Via I2C Bus, in Any Combination
* Power-up With All Switch Channels Deselected
* Low RON Switches
* Allows Voltage-Level Translation Between 1.8V, 2.5V, 3.3V and 5V Buses
* No Glitch on Power-up
* Supports Hot Insertion
* Low Standby Current
* Operating Power-Supply Voltage Range of 2.3V to 5.5V
* 5.5-V Tolerant Inputs
* 0 to 400-kHz Clock Frequency |
