Diodes Incorporated

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Hot Swappable I2C-bus and SMBus Buffer

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The PI6ULS5V9511B is a hot-swappable I2 C-bus and SMBus buffer that allows I/O card insertion into a live backplane without corrupting the data and clock buses. Control circuitry prevents the backplane from connecting to the card until a stop command or bus idle occurs on the backplane without bus contention on the card.
When the connection is made, the PI6ULS5V9511B provides bidirectional buffering, which keeps the backplane and card capacitances isolated. The PI6ULS5V9511B rise-time accelerator circuitry allows the use of weaker DC pullup currents while still meeting
rise-time requirements. The PI6ULS5V9511B incorporates a digital ENABLE input pin, which enables the device when asserted HIGH and forces the device into a low-current
mode when asserted LOW. The PI6ULS5V9511B also incorporates an open-drain READY output pin, which indicates that the backplane and card sides are connected
together (HIGH) or not (LOW). During insertion, the PI6ULS5V9511B SDA and SCL lines
are pre-charged to 1.1V to minimize the current required to charge the parasitic capacitance of the chip.


  • Bidirectional Buffer for SDA and SCL Lines Increases
    Fan Out
  • Prevents SDA and SCL Corruption During Live Board
    Insertion and Removal from Backplane
  • Isolates Input SDA and SCL Lines From Output
  • Compatible with I2C, I2C Fast Mode, and SMBus Standards (up to 400kHz Operation)
  • Built-in Rise-Time Accelerators on all SDA and SCL
  • Wide Supply Voltage Range: 2.7V to 5.5V
  • Active HIGH ENABLE Input
  • Active HIGH READY Open-Drain Output
  • High-Impedance SDA and SCL pins for VCC = 0V
  • 1.1V Pre-Charge on all SDA and SCL Lines
  • Supports Clock Stretching and Multiple Master
  • ESD Protection Exceeds 4000V HBM per JESD22-A114
  • Totally Lead-Free & Fully RoHS Compliant 
  • Halogen and Antimony Free. “Green” Device 
  • For automotive applications requiring specific change
    control (i.e. parts qualified to AEC-Q100/101/200, PPAP
    capable, and manufactured in IATF 16949 certified
    facilities), please contact us or your local Diodes
  • Packages (Pb-free and Green):
    • MSOP-8 (U),
    • SOIC-8 (W)

Product Specifications

Product Parameters

Compliance (Only Automotive supports PPAP) Standard
Translation From (V) 0.8 to 5.5
Translation To (V) 0.8 to 5.5
Max Signal Rate 400kHz
Bits Needed 2
Auto Direction Sensing? Yes
Shift Bi-Directional
Prop Delay (ns) 70
Ambient or Junction Temperature (°C) -40 to 85

Technical Documents

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)