1 Features

• Two-Channel Bidirectional Buffer

• I2C Bus and SMBus Compatible

• Operating Supply Voltage Range of 0.9V to 5.5V

on A-side

• Operating Supply Voltage Range of 2.7V to 5.5V

on B-side

• Voltage-Level Translation From 0.9V - 5.5V to

2.7V - 5.5V

• Footprint and Functional Replacement for

PCA9515B

• Active-High Repeater-Enable Input

• Open-Drain I2C I/O

• 5.5V Tolerant I2C and Enable Input Support Mixed-

Mode Signal Operation

• Accommodates Standard Mode and Fast Mode

I2C Devices and Multiple Masters

• High-Impedance I2C Pins When Powered-Off

• Latch-Up Performance Exceeds 100mA Per JESD

78, Class II

• ESD Protection Exceeds JESD 22

– 5500V Human-Body Model (A114-A)

– 200V Machine Model (A115-A)

– 1000V Charged-Device Model (C101)

2 Applications

• Servers

• Routers (Telecom Switching Equipment)

• Industrial Equipment

• Products with Many I2C Slaves and/or Long PCB

Traces

3 Description

The TCA9517A is a bidirectional buffer with level

shifting capabilities for I2C and SMBus systems.

It provides bidirectional voltage-level translation (uptranslation/

down-translation) between low voltages

(down to 0.9V) and higher voltages (2.7V to 5.5V)

in mixed-mode applications. This device enables

I2C and SMBus systems to be extended without

degradation of performance, even during level

shifting.

The TCA9517A buffers both the serial data (SDA) and

the serial clock (SCL) signals on the I2C bus, thus

allowing two buses of up to 400pF bus capacitance to

be connected in an I2C application.

The TCA9517A has two types of drivers: A-side

drivers and B-side drivers. All inputs and I/Os are

over-voltage tolerant to 5.5V, even when the device

is unpowered (VCCB and/or VCCA = 0V).

The TCA9517A offers a higher contention level

threshold, VILC, than the TCA9517, which allows

connections to slaves which have weaker pulldown

ability.

The type of buffer design on the B-side prevents it

from being used in series with devices which use

static voltage offset. This is because these devices

do not recognize buffered low signals as a valid low

and do not propagate it as a buffered low again.

The B-side drivers operate from 2.7 V to 5.5 V.

The output low level for this internal buffer is

approximately 0.5 V, but the input voltage must be

70 mV or more below the output low level when the

output internally is driven low. The higher-voltage low

signal is called a buffered low. When the B-side I/O

is driven low internally, the low is not recognized as

a low by the input. This feature prevents a lockup

condition from occurring when the input low condition

is released.