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SCPS113I – OCTOBER 2004 – REVISED JULY 2008
DUAL BIDIRECTIONAL I
2
C BUS AND SMBus
VOLTAGE-LEVEL TRANSLATOR
1
FEATURES
2-Bit Bidirectional Translator for SDA and SCL
Lines in Mixed-Mode I
2
C Applications
I
2
C and SMBus Compatible
Less Than 1.5-ns Maximum Propagation Delay
to Accommodate Standard-Mode and
Fast-Mode I
2
C Devices and Multiple Masters
Allows Voltage-Level Translator Between
– 1.2-V V
REF1
and 1.8-V, 2.5-V, 3.3-V,
or 5-V V
REF2
– 1.8-V V
REF1
and 2.5-V, 3.3-V, or 5-V V
REF2
– 2.5-V V
REF1
and 3.3-V or 5-V V
REF2
– 3.3-V V
REF1
and 5-V V
REF2
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 I
2
C I/O Ports (SCL1, SDA1, SCL2,
and SDA2)
5-V Tolerant I
2
C I/O Ports to Support
Mixed-Mode Signal Operation
High-Impedance SCL1, SDA1, SCL2, and SDA2
Pins for EN = Low
•
•
•
•
Lock-Up-Free Operation for Isolation When
EN = Low
Flow-Through Pinout for Ease of Printed
Circuit Board Trace Routing
Latch-Up Performance Exceeds 100 mA Per
JESD 78, Class II
ESD Protection Exceeds JESD 22
– 2000-V Human-Body Model (A114-A)
– 200-V Machine Model (A115-A)
– 1000-V Charged-Device Model (C101)
DCT OR DCU PACKAGE
(TOP VIEW)
•
•
•
•
•
•
GND
V
REF1
SCL1
SDA1
1
2
3
4
8
7
6
5
EN
V
REF2
SCL2
SDA2
•
•
•
DESCRIPTION/ORDERING INFORMATION
This dual bidirectional I
2
C and SMBus voltage-level translator, with an enable (EN) input, is operational from
1.2-V to 3.3-V V
REF1
and 1.8-V to 5.5-V V
REF2
.
The PCA9306 allows bidirectional voltage translations between 1.2 V and 5 V, without the use of a direction pin.
The low ON-state resistance (r
on
) 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.
In I
2
C applications, the bus capacitance limit of 400 pF restricts the number of devices and bus length. Using the
PCA9306 enables the system designer to isolate two halves of a bus; thus, more I
2
C devices or longer trace
length can be accommodated.
The PCA9306 also can 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 master is running at 400 kHz, the maximum
system operating frequency may be less than 400 kHz because of the delays added by the repeater.
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2004–2008, Texas Instruments Incorporated
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