TCA4311A Datasheet, PDF (1/22 Pages) Texas Instruments – HOT SWAPPABLE 2-WIRE BUS BUFFERS

TCA4311A
www.ti.com
HOT SWAPPABLE 2-WIRE BUS BUFFERS
Check for Samples: TCA4311A
SCPS226 – JANUARY 2011
FEATURES
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• Operating Power-Supply Voltage Range of
2.7-V to 5.5-V
• Supports Bidirectional Data Transfer of I²C
Bus Signals
• SDA and SCL Lines Are Buffered Which
Increases Fanout
• 1-V Precharge on All SDA and SCL Lines
Prevents Corruption During Live Board
Insertion and Removal From Backplane
• SDA and SCL Input Lines Are Isolated From
Outputs
• Accommodates Standard Mode and Fast Mode
I²C Devices
• Improved Noise Immunity
• Applications Include Hot Board Insertion and
Bus Extension
• Low I_CC Chip Disable of <1 mA
• READY Open-Drain Output
• Supports Clock Stretching, Arbitration, and
Synchronization
• Powered-Off High-Impedance I²C Pins
• Open-Drain I²C Pins
• Latch-Up Performance Exceeds 100 mA Per
JESD 78, Class II
• ESD Protection Exceeds JESD 22
– 8000-V Human-Body Model (A114-A)
– 200-V Machine Model (A115-A)
– 1000-V Charged-Device Model (C101)
D OR DGK PACKAGES
(TOP VIEW)
EN 1
SCLOUT 2
SCLIN 3
GND 4
8 V_CC
7 SDAOUT
6 SDAIN
5 READY
DESCRIPTION/ORDERING INFORMATION
The TCA4311A is a hot swappable I²C bus buffer that supports I/O card insertion into a live backplane without
corruption of the data and clock busses. Control circuitry prevents the backplane from being connected to the
card until a stop command or bus idle occurs on the backplane without bus contention on the card. When the
connection is made, this device provides bidirectional buffering, keeping the backplane and card capacitances
isolated. During insertion, the SDA and SCL lines are precharged to 1 V to minimize the current required to
charge the parasitic capacitance of the chip.
When the I²C bus is idle, the TCA4311A can be put into shutdown mode by setting the EN pin low. When EN is
high, the TCA4311A resumes normal operation. It also includes an open drain READY output pin, which
indicates that the backplane and card sides are connected together. When READY is high, the SDAIN and
SCLIN are connected to SDAOUT and SCLOUT. When the two sides are disconnected, READY is low.
Both the backplane and card may be powered with supply voltages ranging from 2.7 V to 5.5 V, with no
restrictions on which supply voltage is higher.
The TCA4311A has standard open-drain I/Os. The size of the pullup resistors to the I/Os depends on the
system, but each side of this buffer must have a pullup resistor. The device is designed to work with Standard
Mode and Fast Mode I²C devices in addition to SMBus devices. Standard Mode I²C devices only specify 3 mA in
a generic I²C system where Standard Mode devices and multiple masters are possible. Under certain conditions,
high termination currents can be used.
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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 © 2011, Texas Instruments Incorporated