Diodes Incorporated
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2-Channel I2C/SMBus Bus Switch

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The PI4MSD5V9543A is a bidirectional translating switch, controlled by the I²C bus. The SCL/SDA channels. Any individual SCx/SDx channels or combination of channels can be selected, determined by
contents of the programmable control register. Two upstream pair fans out to two downstream pairs, or the interrupt inputs, INT0 and INT1, one for each of the downstream pairs, are provided. One interrupt output,
INT, which acts as an AND of the two interrupt inputs, is provided.
An active LOW reset input allows the PI4MSD5V9543A to recover from a situation where one of the downstream 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 VCC pin can be used to limit the maximum high voltage which will be passed by the PI4MSD5V9543A. This allows the use of different bus voltages
on each SCx/SDx pair, so that 1.2V,1.8 V, 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 5V tolerant.


  • 1-of-2 bidirectional translating multiplexer
  • I²C-bus interface logic
  • Operating power supply voltage:1.65V to 5.5V
  • Allows voltage level translation between 1.2V, 1.8V, 2.5V, 3.3V and 5V 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
  • 5V tolerant inputs
  • 0 Hz to 400 kHz clock frequency
  • ESD protection exceeds 8000 V HBM per JESD22-A114, and 1000V CDM per JESD22-C101
  • Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA
  • Packages offered: SOIC-14W,TSSOP-14L

Product Specifications

Product Parameters

Ambient or Junction Temperature (°C) -40 to 85
Analog or Digital? Digital
Voltage 1.65V/5.5V
Single Ended Channels 2
Signal Type Single Ended
Configuration Switch, 2-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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Product Change Notices (PCNs)

A PCN may only apply to specific orderable part numbers in this datasheet. Please refer to the corresponding PCN to see the exact orderable part number(s) affected.

PCN # Issue Date Implementation Date Subject
PCN-2642 2023-09-05 2024-03-05 Device End of Life (EOL)
PCN-2493 2020-12-28 2021-03-28 Qualified Additional A/T Sites and Bill of Materials (BOM)