Datasheet LTC4304 (Analog Devices)

LTC4304 Hot Swappable 2-Wire Bus Buffer with Stuck Bus Recovery
U FEATURES DESCRIPTIO
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Automatic Disconnect of SDA/SCL Lines when Bus
The LTC®4304 hot swappable 2-wire bus buffer allows I/O
is Stuck Low for ≥30ms
card insertion into a live backplane without corruption of ■
Fault Flag for Stuck Bus
the data and clock busses. When a connection is made, ■
Recovers Stuck Busses with Automatic Clocking*
the LTC4304 provides bidirectional buffering, keeping the ■
Bidirectional Buffer* for SDA and SCL Lines
backplane and card capacitances isolated. If SDAOUT or
Increases Fanout
SCLOUT is low for ≥30ms (typ), the LTC4304 automatically ■
Prevents SDA and SCL Corruption During Live
breaks the data and clock bus connection and FAULT will
Board Insertion and Removal from Backplane
pull low. At this time the LTC4304 automatically generates ■
Allows Bus Pullup Voltages Above and Below VCC
up to 16 clock pulses on SCLOUT in an attempt to free the ■
±15kV Human Body Model ESD Protection
bus. A connection will be enabled automatically when the ■

Isolates Input SDA and SCL Lines from Output bus becomes free. A logic low on the ACC input enables ■

Compatible with I2CTM, I2C Fast-Mode and SMBus the LTC4304’s rise-time accelerators. A logic high on ACC Standards (Up to 400kHz Operation) disables the rise-time accelerators, which allows SDA and ■

READY Open Drain Output SCL bus pull-up voltages below VCC. ■

1V Precharge on All SDA and SCL Lines During insertion, the SDA and SCL lines are precharged ■

High Impedance SDA, SCL Pins for VCC = 0V to 1V to minimize bus disturbances. When driven high, ■

ENABLE Gates Connection from Input to Output ENABLE allows the LTC4304 to connect after a stop bit or ■

MSOP 10-Pin and DFN (3mm × 3mm) Packages bus idle occurs. Driving ENABLE low breaks the connection
U
between SDAIN and SDAOUT, SCLIN and SCLOUT. READY
APPLICATIO S
is an open drain output that indicates when the backplane ■

Hot Board Insertion and card sides are connected together. ■

Servers ■

Capacitance Buffer/Bus Extender , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. ■

RAID Systems Protected by U.S. Patents including 6356140, 6650174, 7032051.
U TYPICAL APPLICATIO
5V 3.3V 0.01µF
Stuck Bus Resolved with Automatic Clocking
10k 10k VCC 10k 10k LTC4304 SDAOUT SCLIN SCLOUT 5V/DIV STUCK LOW > 30ms RECOVERS BACK_SCL CARD_SCL SDAIN DISCONNECT AT TIMEOUT 5V/DIV AUTOMATIC CLOCKING SDAIN SDAOUT SCLOUT BACK_SDA CARD_SDA 5V/DIV FAULT READY FAULT 3.3V ENABLE ACC GND 5V/DIV 100k 4304 TA01 4304 TA01b 200ms/DIV BACKPLANE STAGGERED CARD CONNECTOR CONNECTOR 4304fa 1