LTC4301_09 Datasheet, PDF (1/12 Pages) Linear Technology – Supply Independent Hot Swappable 2-Wire Bus Buffer

LTC4301
Supply Independent Hot
Swappable 2-Wire Bus Buffer
FEATURES
■ _{Allows Bus Pull-Up Voltages Above or Below VCC}
■ _{Bidirectional Buffer* for SDA and SCL Lines}
Increases Fanout
■ _{Prevents SDA and SCL Corruption During Live Board}
Insertion and Removal from Backplane
■ _{Isolates Input SDA and SCL Line from Output}
■ _{10kV Human Body Model ESD Protection}
■ _{1V Precharge On All SDA and SCL Lines}
■ _{Supports Clock Stretching, Arbitration and}
Synchronization
■ _{High Impedance SDA, SCL Pins for VCC = 0V}
■ _{CS Gates Connection from Input to Output}
■ _{Compatible with I}²_C^TM_{, I}²_{C Fast Mode and SMBus}
Standards (Up to 400kHz Operation)
■ _{Small 8-Pin MSOP and DFN (3mm × 3mm) Packages}
U
APPLICATIO S
■ _{Hot Board Insertion}
■ _Servers
■ _{Capacitance Buffer/Bus Extender}
■ _{Desktop Computers}
■ _CompactPCI^TM _{and ATCA Systems}
DESCRIPTIO
The LTC^®4301 supply independent, hot swappable, 2-wire
bus buffer allows I/O card insertion into a live backplane
without corruption of the data and clock busses. In addi-
tion, the LTC4301 allows the V_CC, SDAIN and SCLIN pull-
up voltage and the SDAOUT and SCLOUT pull-up voltage
to be independent from each other. Control circuitry
prevents the backplane from being connected to the card
until a stop bit or a bus idle is present. When the connec-
tion is made, the LTC4301 provides bidirectional buffer-
ing, keeping the backplane and card capacitances isolated.
During insertion, the SDA and SCL lines are precharged to
1V to minimize bus disturbances. When driven low, the CS
input pin allows the part to connect after a stop bit or bus
idle occurs. Driving CS high breaks the connection be-
tween SCLIN and SCLOUT and between SDAIN and
SDAOUT. The READY output pin indicates that the back-
plane and card sides are connected together.
The LTC4301 is offered in 8-pin DFN (3mm × 3mm) and
MSOP packages.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Protected by U.S. Patents including 7032051.
TYPICAL APPLICATIO
3.3V 5V
10k 10k
BACK_SCL
BACK_SDA
BACKPLANE
CONNECTOR
0.01µF
SCLIN
V_CC
LTC4301
SCLOUT
SDAIN
5V
10k
CS
GND
SDAOUT
READY
4301 TA01
10k 10k
CARD_SCL
CARD_SDA
OUTPUT
SIDE
20pF
1V/DIV
CARD
Input-Output Connection
INPUT
SIDE
55pF
1µs/DIV
4301 TA01b
4301fb
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