TCA9511A Hot swappable I2C bus and SMBus buffer |

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Hot swappable I2C bus and SMBus buffer



The TCA9511A is a hot-swappable I2C bus buffer that supports I/O card insertion into a live backplane without corruption of the data and clock buses. Control circuitry prevents the backplane-side I2C lines (in) from being connected to the card-side I2C lines (out) until a stop command or bus idle condition occurs on the backplane without bus contention on the card. When the connection is made, this device provides bidirectional buffering, keeping the backplane and card capacitances separated. During insertion, the SDA and SCL lines are pre-charged to 1 V to minimize the current required to charge the parasitic capacitance of the device.

When the I2C bus is idle, the TCA9511A can be put into shutdown mode by setting the EN pin low, reducing power consumption. When EN is pulled high, the TCA9511A resumes normal operation. It also includes an open drain READY output pin, which indicates that the backplane and card sides are connected together. When READY is high, the SDAIN and SCLIN are connected to SDAOUT and SCLOUT. When the two sides are disconnected, READY is low.


  • Supports bidirectional data transfer of I2C bus signals
  • Operating power-supply voltage range of 2.3 V to 5.5 V
  • TA ambient air temperature range of
    -40 °C to 125 °C
  • 1-V Precharge on all SDA and SCL lines prevents corruption during live insertion
  • Accommodates standard mode and fast mode I2C devices
  • Supports clock stretching, arbitration and synchronization
  • Powered-off high-impedance I2C pins

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Part number Order VCCA (Min) (V) VCCA (Max) (V) VCCB (Min) (V) VCCB (Max) (V) Supply restrictions Frequency (Max) (kHz) Features Operating temperature range (C) Approx. price (US$) Package Group Rating
TCA9511A Order now 2.3     5.5     2.3     5.5     VCC Single Supply     400     Buffer
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-40 to 125     0.84 | 1ku     VSSOP | 8     Catalog    
TCA4311A Order now 2.7     5.5     2.7     5.5     VCC Single Supply     400     Buffer
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-40 to 85     0.43 | 1ku     SOIC | 8
VSSOP | 8