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 TCA9800 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
TCA9800 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 TCA9800 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 TCA9800
are very low (approximately 0.2 V), helping to
eliminate communication issues as a result of fixed
VIL thresholds. Another key feature of the TCA9800 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 TCA9800 is
used.
The TCA9800 is part of a four device family with
varying current source strengths (see the Device
Comparison Table).