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Level Translating I2C Bus Repeater


Package | PIN: RVH | 8
Temp: I (-40 to 85)
Carrier: Cut Tape
Qty Price
1-9 $0.78
10-24 $0.69
25-99 $0.65
100-249 $0.56
250-499 $0.52
500-749 $0.44
750-999 $0.36
1000+ $0.33


  • Two-Channel Bidirectional Buffer
  • I2C Bus and SMBus Compatible
  • Operating Supply Voltage Range of
    2.7 V to 5.5 V on B side
  • Operating Voltage Range of 0.9 V to 5.5 V on
  • Voltage-Level Translation From
    0.9 V to 5.5 V and 2.7 V to 5.5 V
  • Active-High Repeater-Enable Input
  • Requires No External Pullup Resistors on
    Lower-Voltage Port-A
  • Open-Drain I2C I/O
  • 5.5-V Tolerant I2C and Enable Input Support Mixed-Mode Signal Operation
  • Lockup-Free Operation
  • Accommodates Standard Mode and Fast Mode I2C Devices and Multiple Masters
  • Supports Arbitration and Clock Stretching Across Repeater
  • Powered-Off High-Impedance I2C Bus Pins
  • Supports 400-kHz Fast I2C Bus Operating Speeds
  • Available in
    • 1.6-mm × 1.6-mm, 0.4-mm height, 0.5-mm Pitch QFN Package
    • 3-mm × 3-mm Industry Standard MSOP Package
  • Latch-Up Performance Exceeds 100 mA Per JESD 78, Class II
  • ESD Protection Exceeds JESD 22
    • 2000-V Human-Body Model (A114-A)
    • 1000-V Charged-Device Model (C101)

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Texas Instruments  TCA9509RVHR

This TCA9509 integrated circuit is an I2C bus/SMBus Repeaterfor use in I2C/SMBus systems. It can also provide bidirectionalvoltage-level translation (up-translation/down-translation) between low voltages (down to 0.9 V)and higher voltages (2.7 V to 5.5 V) in mixed-mode applications. This device enablesI2C and similar bus systems to be extended, without degradation ofperformance even during level shifting.

The TCA9509 buffers both the serial data (SDA) and the serial clock (SCL) signals on theI2C bus, thus allowing 400-pF bus capacitance on the B-side. This devicecan also be used to isolate two halves of a bus for voltage and capacitance.

The TCA9509 has two types of drivers – A-side drivers and B-side drivers. All inputs andB-side I/Os are overvoltage tolerant to 5.5 V. The A-side I/Os are overvoltage tolerant to 5.5 Vwhen the device is unpowered (VCCB and/or VCCA = 0 V).

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

The TCA9509 drivers are not enabled unless VCCA is above 0.8 V andVCCB is above 2.5 V. The enable (EN) pin can also be used to turn thedrivers on and off under system control. Caution should be observed to only change the state of theEN pin when the bus is idle.