LTC4303

1

4303fb

FEATURES

DESCRIPTIO

TYPICAL APPLICATIO

APPLICATIO S

10k

10k

5V

BACK_SCL

BACKPLANE

CONNECTOR

CARD

BACK_SDA

3.3V

3.3V

100k

ENABLE

CARD_SCL

CARD_SDA

SCLOUT

SCLIN

SDAOUT

SDAIN

GND

LTC4303

READY

0.01

mF

10k

10k

STAGGERED

CONNECTOR

, 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 6356140, 6650174, 7032051.

Hot Swappable 2-Wire

Bus Buffer with Stuck

Bus Recovery

card insertion into a live backplane without corruption of

the data and clock busses. When a connection is made,

the LTC4303 provides bidirectional buffering, keeping the

backplane and card capacitances isolated. If SDAOUT or

SCLOUT is low for ≥ 30ms (typ), the LTC4303 automatically

breaks the data and clock bus connection. At this time the

LTC4303 automatically generates up to 16 clock pulses on

SCLOUT in an attempt to free the bus. A connection will

be enabled automatically when the bus becomes free.

Rise-time accelerator circuitry allows the use of larger pull-

up resistance while still meeting rise-time requirements.

During insertion, the SDA and SCL lines are precharged

to 1V to minimize bus disturbances. When driven high,

ENABLE allows the LTC4303 to connect after a stop bit or

bus idle occurs. Driving ENABLE low breaks the connection

between SDAIN and SDAOUT, SCLIN and SCLOUT. READY

is an open drain output that indicates when the backplane

and card sides are connected together.

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Automatic Disconnect of SDA/SCL Lines when Bus

is Stuck Low for ≥ 30ms

■

Recovers Stuck Busses with Automatic Clocking*

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Bidirectional Buffer* for SDA and SCL Lines

Increases Fanout

■

Prevents SDA and SCL Corruption During Live

Board Insertion and Removal from Backplane

■

Pin Compatible with LTC4300A-1

■

±15kV Human Body Model ESD Protection

■

Isolates Input SDA and SCL Lines from Output

■

Standards (Up to 400kHz Operation)

■

READY Open Drain Output

■

1V Precharge on All SDA and SCL Lines

■

■

ENABLE Gates Connection from Input to Output

■

MSOP 8-Pin and DFN (3mm

× 3mm) Packages

■

Hot Board Insertion

■

Servers

■

Capacitance Buffer/Bus Extender

■

RAID Systems

Stuck Bus Resolved

with Automatic Clocking

SDAOUT

5V/DIV

200

ms/DIV

STUCK LOW > 30ms

AUTOMATIC CLOCKING

DISCONNECT AT TIMEOUT

RECOVERS

4303 TA01b

SDAIN

5V/DIV

SCLOUT

5V/DIV