TCA9801

• Two-channel bidirectional buffer
• Integrated current source on B-side, requires no external B-side resistors
• Ultra-low power consumption
• No static-voltage offset, low V_OL
• I²C bus and SMBus compatible
• Operating supply voltage range of 0.8 V to 3.6 V on A-side
• Operating supply voltage range of 1.65 V to 3.6 V on B-side
• Active-high repeater enable input
• Powered-off high impedance I²C bus pins on A-side
• Powered-off back-power protection I²C bus pins
• Support for clock stretching and multiple master arbitration
• Family of current source options from 0.5 mA to 3 mA

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The TCA9801 is a dual-channel bidirectional buffer intended for I²C bus and SMBus/PMBus systems. It provides bidirectional level shifting (up-translation and down-translation) between low voltages (down to 0.8 V) and higher voltages (1.65 V to 3.6 V). The TCA9801 features an internal current source on the B-side of the device, allowing the removal of external pull-up resistors on the B-side. The current source also provides an improved rise time and ultra-low power consumption.

The TCA9801 is able to provide true buffering (rather than a pass-FET solution) without using a static voltage offset or incremental offset. This means that the V_OL on both the A and B sides of the TCA9801 are very low (approximately 0.2 V), helping to eliminate communication issues as a result of fixed V_IL thresholds. Another key feature of the TCA9801 is that there are no power sequencing requirements, or power supply dependencies. V_CCA can be greater than, less than, or equal to V_CCB. This gives the system designer flexibility with how the TCA9801 is used.

The TCA9801 is part of a four device family with varying current source strengths (see the Device Comparison Table).