4-channel I2C-bus multiplexer with interrupt logic
The NCA9544 is a 1-of-4 bidirectional translating multiplexer controlled via the I2C bus. The SCL/SDA upstream pair fans out to one of the four downstream pairs, or channels. Only one SCn/SDn channel is selected at a time, 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 (/INT) output acts as an AND of the four interrupt inputs. A power-on reset function returns the registers to their default state and initializes the I2C state machine, with all channels deselected. The pass gates of the multiplexer are constructed such that the VCC terminal can be used to limit the maximum high voltage, which will be passed by the NCA9544. 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 terminals are 5.5V tolerant.
Product Features
1-of-4 Bidirectional Translating multiplexer
I2C Bus and SMBus Compatible
Four Active-Low Interrupt Inputs
Active-Low Interrupt Output
Three Address Terminals, Allowing up to eight Devices on the I2C Bus
Channel Selection via I2C Bus
Power-Up with All Switch Channels Deselected
Low RON Switches
Allows Voltage-Level Translation Between 1.8-V, 2.5-V, 3.3-V, and 5-V Buses
No Glitch on Power-Up
Operating Power-Supply Voltage Range of 1.65 V to 5.5 V
5.5V Tolerant Inputs
0 to 400-kHz Clock Frequency
Latch-Up Performance Exceeds 100 mA per JESD 78
RoHS & REACH compliant
ESD Protection Exceeds JESD 22:
– 2000-V Human-Body Model (A114-A)
– 1000-V Charged-Device Model (C101)
Application
Servers
Routers (Telecom Switching Equipment)
Factory Automation
Products with I2C Slave Address Conflicts (e.g. Multiple, Identical Temp Sensors)
Functional Block Diagram
For more product information, please contact us.
