LTC4300A-1/LTC4300A-2

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sn4300a12 4300a12fs

The LTC

allow I/O card insertion into a live backplane without

corruption of the data and clock busses. When the con-

nection is made, the LTC4300A-1/LTC4300A-2 provide

bidirectional buffering, keeping the backplane and card

capacitances isolated. Rise-time accelerator circuitry*

allows the use of weaker DC pull-up currents while still

meeting rise-time requirements. During insertion, the

SDA and SCL lines are precharged to 1V to minimize bus

disturbances.

The LTC4300A-1 incorporates a CMOS threshold digital

ENABLE input pin, which forces the part into a low current

modewhendriventogroundandsetsnormaloperationwhen

pin, which indicates that the backplane and card sides are

connected together. The LTC4300A-2 replaces the ENABLE

side, providing level shifting between 3.3V and 5V systems.

Both the backplane and card may be powered with supply

voltages ranging from 2.7V to 5.5V, with no contraints on

which supply voltage is higher. The LTC4300A-2 also re-

places the READY pin with a digital CMOS input pin, ACC,

whichenablesanddisablestherise-timeacceleratorcurrents.

The LTC4300A is available in a small 8-pin MSOP package.

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Hot Board Insertion

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Servers

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Capacitance Buffer/Bus Extender

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Desktop Computer

, LTC and LT are registered trademarks of Linear Technology Corporation.

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Bidirectional Buffer for SDA and SCL Lines

Increases Fanout

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Prevents SDA and SCL Corruption During Live

Board Insertion and Removal from Backplane

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Isolates Input SDA and SCL Lines from Output

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Standards (Up to 400kHz Operation)

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Small MSOP 8-Pin Package

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READY Open Drain Output (LTC4300A-1)

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1V Precharge on all SDA and SCL Lines

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Supports Clock Stretching, Arbitration and

Synchronization

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5V to 3.3V Level Translation (LTC4300A-2)

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Hot Swappable

2-Wire Bus Buffers

*U.S. Patent No. 6,650,174

R1

10k

3.3V

R2

10k

ENABLE

SCLIN

SCLOUT

SDAIN

SDAOUT

15

4

67

32

8

GND

LTC4300A-1

READY

C1

0.01

µF

R3

10k

R4

10k

APPLICATIO S

FEATURES

TYPICAL APPLICATIO

DESCRIPTIO

OUTPUT

SIDE

50pF

INPUT

SIDE

150pF

4300A TA02