General description

The PCA9306 is a dual bidirectional I2C-bus and SMBus voltage-level translator with

an enable (EN) input, and is operational from 1.0 V to 3.6 V (Vref(1)) and 1.8 V to 5.5 V

(Vbias(ref)(2)).

The PCA9306 allows bidirectional voltage translations between 1.0 V and 5 V without the

use of a direction pin. The low ON-state resistance (Ron) of the switch allows connections

to be made with minimal propagation delay. When EN is HIGH, the translator switch is

on, and the SCL1 and SDA1 I/O are connected to the SCL2 and SDA2 I/O, respectively,

allowing bidirectional data flow between ports. When EN is LOW, the translator switch is

off, and a high-impedance state exists between ports.

The PCA9306 is not a bus buffer like the PCA9509 or PCA9517A that provide both level

translation and physically isolate the capacitance to either side of the bus when both

sides are connected. The PCA9306 only isolates both sides when the device is disabled

and provides voltage level translation when active.

The PCA9306 can also be used to run two buses, one at 400 kHz operating frequency

and the other at 100 kHz operating frequency. If the two buses are operating at different

frequencies, the 100 kHz bus must be isolated when the 400 kHz operation of the other

bus is required. If the controller is running at 400 kHz, the maximum system operating

frequency may be less than 400 kHz because of the delays added by the translator.

As with the standard I2C-bus system, pull-up resistors are required to provide the

logic HIGH levels on the translator’s bus. The PCA9306 has a standard open-collector

configuration of the I2C-bus. The size of these pull-up resistors depends on the system,

but each side of the translator must have a pull-up resistor. The device is designed to

work with Standard-mode, Fast-mode and Fast-mode Plus I2C-bus devices in addition

to SMBus devices. The maximum frequency is dependent on the RC time constant, but

generally supports > 2 MHz.

When the SDA1 or SDA2 port is LOW, the clamp is in the ON-state and a low resistance

connection exists between the SDA1 and SDA2 ports. Assuming the higher voltage is on

the SDA2 port when the SDA2 port is HIGH, the voltage on the SDA1 port is limited to

the voltage set by VREF1. When the SDA1 port is HIGH, the SDA2 port is pulled to the

drain pull-up supply voltage (Vpu(D)) by the pull-up resistors. This functionality allows a

seamless translation between higher and lower voltages selected by the user without the

need for directional control. The SCL1/SCL2 channel also functions as the SDA1/SDA2

channel.

All channels have the same electrical characteristics and there is minimal deviation from

one output to another in voltage or propagation delay. This is a benefit over discrete

transistor voltage translation solutions, since the fabrication of the switch is symmetrical.

The translator provides excellent ESD protection to lower voltage devices, and at the

same time protects less ESD-resistant devices.

Features and benefits

• 2-bit bidirectional translator for SDA and SCL lines in mixed-mode I2C-bus applications

• Standard-mode, Fast-mode, and Fast-mode Plus I2C-bus and SMBus compatible

• Less than 1.5 ns maximum propagation delay to accommodate Standard-mode and

Fast-mode I2C-bus devices and multiple controllers

• Allows voltage level translation between:

– 1.0 V Vref(1) and 1.8 V, 2.5 V, 3.3 V or 5 V Vbias(ref)(2)

– 1.2 V Vref(1) and 1.8 V, 2.5 V, 3.3 V or 5 V Vbias(ref)(2)

– 1.8 V Vref(1) and 3.3 V or 5 V Vbias(ref)(2)

– 2.5 V Vref(1) and 5 V Vbias(ref)(2)

– 3.3 V Vref(1) and 5 V Vbias(ref)(2)

• Provides bidirectional voltage translation with no direction pin

• Low 3.5 Ω ON-state connection between input and output ports provides less signal

distortion

• Open-drain I2C-bus I/O ports (SCL1, SDA1, SCL2 and SDA2)

• 5 V tolerant I2C-bus I/O ports to support mixed-mode signal operation

• High-impedance SCL1, SDA1, SCL2 and SDA2 pins for EN = LOW

• Lock-up free operation

• Flow through pinout for ease of printed-circuit board trace routing

• ESD protection exceeds 2000 V HBM per JESD22-A114 and 1000 V CDM per

JESD22-C101

• Packages offered: SO8, TSSOP8, VSSOP8, XQFN8, XSON8, X2SON8