1 Features

1• 2-Bit Bidirectional Translator for SDA and SCL

Lines in I2C Applications

• Provides Bidirectional Voltage Translation With No

Direction Pin

• High-Impedance Output SCL_A, SDA_A, SCL_B,

SDA_B Pins When OE = Low or VCC = 0 V

• Internal 10-kΩ Pullup Resistor on All SDA and

SCL Pins

• 1.65 V to 3.6 V on A port and 2.3 V to 5.5 V on B

port (VCCA ≤ VCCB)

• VCC Isolation Feature: If Either VCC Input Is at

GND, Both Ports Are in the High-Impedance State

• No Power-Supply Sequencing Required: Either

VCCA or VCCB Can Be Ramped First

• Low Ioff of 2 μA When Either VCCA or VCCB = 0 V

• OE Input Can Be Tied Directly to VCCA Or

Controlled By GPIO

• Latch-Up Performance Exceeds 100 mA Per

JESD 78, Class II

• ESD Protection Exceeds JESD 22

– A Port

– 2500-V Human-Body Model (A114-B)

– 250-V Machine Model (A115-A)

– 1500-V Charged-Device Model (C101)

– B Port

– 8-kV Human-Body Model (A114-B)

– 250-V Machine Model (A115-A)

– 1500-V Charged-Device Model (C101)

2 Applications

• I2C/SMBus

• UART

• GPIO

3 Description

The TCA9406 is a 2-bit bidirectional I2C and SMBus

voltage-level translator with an output enable (OE)

input. It is operational from 1.65 V to 3.6 V on the Aside,

referenced toVCCA, and from 2.3 V to 5.5 V on

the B-side, referenced to VCCB. This allows the device

to interface between lower and higher logic signal

levels at any of the typical 1.8-V, 2.5-V, 3.3-V, and

5-V supply rails.

The OE input pin is referenced to VCCA, can be tied

directly to VCCA, but it is also 5.5-V tolerant. The OE

pin can also be controlled and set to a logic low to

place all the SCL and SDA pins in a high-impedance

state, which significantly reduces the quiescent

current consumption.

Under normal I2C and SMBus operation or other

open-drain configurations, the TCA9406 can support

up to 2 Mbps; therefore, it is compatible with standard

I2C speeds where the frequency of SCL is 100 kHz

(Standard-mode), 400 kHz (Fast-mode), or 1 MHz

(Fast-mode Plus). The device can also be used as a

general purpose level translator, and when the A- and

B-side ports are both driven with push-pull devices

the TCA9406 can support up to 24 Mbps.

The TCA9406 features internal 10-kΩ pullup resistors

on SCL_A, SDA_A, SCL_B, and SDA_B. Additional

external pullup resistors can be added to the bus to

reduce the total pullup resistance and speed up rising

edges.