Diodes Incorporated
Back to Universal Level Shifter / Voltage Translation (ULS)


Level Translating I2C-Bus/SMBus Repeater with Tiny Package

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Product Description

The PI6ULS5V9509 is a level translating I2Cbus/SMBus repeater. It can provide bidirectional level translation between low voltage (down to 1.1V) and higher voltage (2.5V to 5.5V) in mixed-mode applications. And it enables I2C and similar bus system to be extended, without degradation of performance even during level shifting.

The PI6ULS5V9509 enables the system designer to isolate two halves of a bus for both voltage and capacitance, accommodating more I2C devices or longer trace length. It also permits extension of the I2C-bus by providing bidirectional buffering for both the data (SDA) and the clock (SCL) lines, thus allowing two buses of 400 pF to be connected in an I2C application.

The bus port B drivers are compliant with SMBus I/O levels, while port A uses a current sensing mechanism to detect the input or output LOW signal which prevents bus lock-up. Port A uses a 1 mA current source for pull-up and a 200Ω pull-down driver. This result in a LOW on the port A accommodating smaller voltage swings. The output pull-down on the port A internal buffer LOW is set for approximately 0.2V, while the input threshold of the internal buffer is set about 50 mV lower than that of the output voltage LOW. When the port A I/O is driven LOW internally, the LOW is not recognized as a LOW by the input. This prevents a lock-up condition from occurring. The output pull-down on the port B drives a hard LOW and the input level is set at 0.3 of SMBus or I2C-bus voltage level which enables port B to connect to any other I2C-bus devices or buffer.

The PI6ULS5V9509 drivers are not enabled unless VCC(A) is above 0.8 V and VCC(B) is above 2.5 V. The enable (EN) pin can also be used to turn the drivers on and off under system control. Caution should be observed to only change the state of the EN pin when the bus is idle.


  • Bidirectional buffer isolates capacitance and allows 400 pF on port B of the device
  • Port A operating supply voltage range of 1.1 V to VCC(B) - 1.0V
  • Port B operating supply voltage range of 2.5 V to 5.5 V
  • Voltage level translation from 1.1V to VCC(B) - 1.0V and from 2.5 V to 5.5 V
  • Requires no external pull-up resistors on lower voltage port A
  • Open-drain port B inputs/outputs
  • Lock-up free operation
  • Supports arbitration and clock stretching across the repeater
  • Accommodates Standard-mode and Fast-mode I2Cbus devices and multiple masters
  • Powered-off high-impedance I2C-bus pins
  • 5 V tolerant B SCL, SDA and enable pins
  • 0 Hz to 400 kHz clock frequency (Remark: The maximum system operating frequency may be less than 400 kHz because of the delays added by the repeater.)
  • ESD protection exceeds 8KV HBM per JESD22- A114
  • Package: MSOP-8, SOIC-8 and UQFN1.6x1.6-8L

Product Specifications

Product Parameters

Compliance (Only Automotive supports PPAP) Standard
Translation From (V) 1.0 to 5.5
Translation To (V) 3.0 to 5.5
Max Signal Rate 400kHz
Bits Needed 2
Auto Direction Sensing? Yes
Shift Bi-Directional
Prop Delay N/A
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-2510 2021-02-26 2021-05-26 Qualified Additional A/T Sites, Fab Site and Data Sheet Change


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