LTC4307 Datasheet, PDF (1/16 Pages) Linear Technology – Low Offset Hot Swappable 2-Wire Bus Buffer with Stuck Bus Recovery

LTC4307
Low Offset Hot Swappable
2-Wire Bus Buffer with Stuck
Bus Recovery
FEATURES
■ _{Bidirectional Buffer with Stuck Bus Recovery}
■ _{60mV Buffer Offset Independent of Load}
■ _{30ms Stuck Bus Timeout}
■ _{Compatible with Non-Compliant VOL I}²_{C Devices}
■ _{Prevents SDA and SCL Corruption During Live}
Board Insertion and Removal from Backplane
■ _{±5kV Human Body Model ESD Protection}
■ _{Isolates Input SDA and SCL Line from Output}
■ _{Compatible with I}²_C^TM_{, I}²_{C Fast Mode and SMBus}
■ _{READY Open-Drain Output}
■ _{1V Precharge on All SDA and SCL Lines}
■ _{High Impedance SDA, SCL Pins for VCC = 0V}
■ _{Small 8-Lead (3mm × 3mm) DFN and 8-Lead MSOP}
Packages
U
APPLICATIO S
■ _{Live Board Insertion}
■ _Servers
■ _{Capacitance Buffer/Bus Extender}
■ _{RAID Systems}
■ _ATCA
DESCRIPTIO
The LTC^®4307 hot swappable, 2-wire bus buffer allows
I/O card insertion into a live backplane without corrup-
tion of the data and clock busses. The LTC4307 provides
bidirectional buffering, keeping the backplane and card
capacitances isolated. Low offset and high V_OL tolerance
allows multiple devices to be cascaded on the clock and
data busses. If SDAOUT or SCLOUT are low for 30ms, the
LTC4307 will automatically break the bus connection. At
this time the LTC4307 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 SDA and SCL lines are pre-charged
to 1V to minimize bus disturbances. When driven high,
the ENABLE input allows the LTC4307 to connect after a
stop bit or bus idle. Driving ENABLE low breaks the con-
nection between SDAIN and SDAOUT, SCLIN and SCLOUT.
READY is an open-drain output which indicates that the
backplane and card sides are connected.
, 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, 6356140, 6650174
TYPICAL APPLICATIO
3.3V
0.01μF
MICRO-
CONTROLLER
10k 10k
V_CC
ENABLE
LTC4307
SCLIN SCLOUT
2.7k 2.7k
V_CC
ENABLE
100k
LTC4307
SCLIN SCLOUT
10k 10k
0.01μF
CARD_SCL
SDAIN SDAOUT
3.3V
10k
READY
GND
SDAIN SDAOUT
3.3V
10k
READY
GND
4307 TA01a
CARD_SDA
BACKPLANE CARD
CONNECTOR CONNECTOR
CARD
Rising Edge from Asserted Low
1000
800
600
LOW
OFFSET
400
SDAOUT
SDAIN
200
0
0 100 200 300 400 500 600
100ns/DIV
4307 TA01b
4307f
1