1 Features

1• 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 VOL

• 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 Aside

• 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

2 Applications

• Servers

• Routers (routing equipment)

• Industrial equipment

• Personal computers

• Power-sensitive applications

3 Description

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 VOL 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

VIL thresholds. Another key feature of the TCA9801 is

that there are no power sequencing requirements, or

power supply dependencies. VCCA can be greater

than, less than, or equal to VCCB. 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).