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4-Channel I2C/SMBus Bus Mux

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The PI4MSD5V9544A is a 1-of-4 bidirectional translating multiplexer, controlled via the I²C bus. The SCL/SDA upstream pair fans out to four SCx/SDx downstream pairs, or channels.
Only one SCx/SDx channel is selected at a time, determined by the contents of the programmable control register. Four interrupt inputs, INT0 to INT3, one for each of the SCx/SDx downstream pairs, are provided.
One interrupt output, INT, which acts as an AND of the four interrupt inputs, is provided.
A power-on reset function puts the registers in their default state and initializes the I2C bus state machine with no channels selected. The pass gates of the multiplexer are constructed such that the VCC pin
can be used to limit the maximum high voltage which will be passed by the PI4MSD5V9544A. This allows the use of different bus voltages on each SCx/SDx pair, so that 1.2V,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.


  • 1-of-4 bidirectional translating multiplexer
  • I²C-bus interface logic;
  • Operating power supply voltage :1.65 V to 5.5 V
  • Allows voltage level translation between 1.2V, 1.8V,2.5 V, 3.3 V and 5 V buses
  • Low standby current
  • Low Ron switches
  • Channel selection via I²C bus
  • Power-up with all multiplexer channels deselected
  • Capacitance isolation when channel disabled
  • No glitch on power-up
  • Supports hot insertion
  • 5 V tolerant inputs
  • 0 Hz to 400 kHz clock frequency
  • ESD protection exceeds 8000 V HBM per JESD22-A114, and 1000 V CDM per JESD22-C101
  • Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA
  • Packages offered: TSSOP-20L

Product Specifications

Product Parameters

Ambient or Junction Temperature (°C) -40 to 85
Analog or Digital? Digital
Voltage 1.65V/5.5V
Single Ended Channels 4
Signal Type Single Ended
Configuration Multiplexer,4-channel, 2:1
RailToRail 0
HotInsertion 1

Technical Documents

Design tool model software

Recommended Soldering Techniques


Additional Technical Documents are available upon request:
Application information, Evaluation board, and Other technical documents

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Orderable Part Number Status Package Environmental Compliance Packing Buy from Distributor /
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Qty. Carrier
PI4MSD5V9544ALEX Active TSSOP-20 TPGP 3000 T&R


Authorized Distributor Quantity Inventory Date Countries/Regions Buy Online
Mouser Electronics Inc. 4354 12/4/2022 South America, North America, Asia, Europe, Middle East Buy Now
Digi-Key Electronics 2650 12/3/2022 Europe, Asia, North America Buy Now
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Environmental Compliance Legend:
LFF: Pb-Free Finish and RoHS 5/6
TLFP: Totally Pb-Free Product and RoHS 6/6
LFGP: Pb-free Finish and Green Product, RoHS 5/6 and Halogen Free
TPGP: Totally Pb-Free and Green Product, RoHS 6/6 and Halogen Free
GREEN: Halogen-free and RoHS compliant
RoHS: RoHS compliant but NOT halogen-free