LTC4308

1

4308f

Low Voltage, Level Shifting

Hot Swappable 2-Wire Bus

Buffer with Stuck Bus Recovery

I/O card insertion into a live backplane without corrup-

tion of the data and clock busses. The LTC4308 provides

bidirectional buffering, keeping the backplane and card

capacitances isolated. Negative offset from output to

input allows communication between output bus devices

where bus supplies can be as low as 0.9V. If SDAOUT or

SCLOUT are low for 30ms, the LTC4308 will automati-

cally break the Input-Output connection. At this time the

LTC4308 automatically generates up to 16 clock pulses

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

will resume if the stuck bus is cleared.

During insertion, the SDAOUT and SCLOUT lines are pre-

charged to 1V to minimize bus disturbances. When driven

high, the ENABLE input allows the LTC4308 to connect after

a stop bit or bus idle condition. Driving ENABLE low breaks

the connection between SDAIN and SDAOUT, SCLIN and

SCLOUT. READY is an open-drain output which indicates

that the backplane and card sides are connected.

Board Insertion and Removal from Backplane

8-Lead MSOP Packages

1.2V to 5V Level Shifting

The LTC4308 in a 1.2V

Microcontroller Application

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. Hot Swap

is a trademark of Linear Technology Corporation. All other trademarks are the property of their

respective owners. Protected by U.S. Patents including 7032051, 6650174, 6356140.

5V

1.2V

2.7k

LTC4308

SCLIN

SDAIN

SCLOUT

SDAOUT

CARD_SCL

READY

CARD_SDA

READY

GND

ENABLE

2.7k

2.7k

10k

4308 TA01a

2.7k

MICRO-

CONTROLLER

0.01μF

1μs/DIV

2V/DIV

CH1

0.5V/DIV

CH2

4308 TA01b

SDAOUT

SDAIN