LTC4307
Low Offset Hot Swappable
2-Wire Bus Buffer with Stuck
Bus Recovery
DESCRIPTIO
FEATURES
Bidirectional Buffer with Stuck Bus Recovery The LTC 4307 hot swappable, 2-wire bus buffer allows
60mV Buffer Offset Independent of Load I/O card insertion into a live backplane without corrup-
30ms Stuck Bus Timeout tion of the data and clock busses. The LTC4307 provides
2
Compatible with Non-Compliant V I C Devices bidirectional buffering, keeping the backplane and card
OL
Prevents SDA and SCL Corruption During Live capacitances isolated. Low offset and high V tolerance
OL
Board Insertion and Removal from Backplane allows multiple devices to be cascaded on the clock and
5kV Human Body Model ESD Protection data busses. If SDAOUT or SCLOUT are low for 30ms, the
Isolates Input SDA and SCL Line from Output LTC4307 will automatically break the bus connection. At
2 TM 2
Compatible with I C , I C Fast Mode and SMBus this time the LTC4307 automatically generates up to 16
READY Open-Drain Output clock pulses on SCLOUT in an attempt to free the bus. A
1V Precharge on All SDA and SCL Lines connection will resume if the stuck bus is cleared.
High Impedance SDA, SCL Pins for V = 0V
CC
During insertion, the SDA and SCL lines are pre-charged
Small 8-Lead (3mm 3mm) DFN and 8-Lead MSOP
to 1V to minimize bus disturbances. When driven high,
Packages
the ENABLE input allows the LTC4307 to connect after a
U
stop bit or bus idle. Driving ENABLE low breaks the con-
APPLICATIO S
nection between SDAIN and SDAOUT, SCLIN and SCLOUT.
READY is an open-drain output which indicates that the
Live Board Insertion
backplane and card sides are connected.
Servers
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
Capacitance Buffer/Bus Extender
All other trademarks are the property of their respective owners.
RAID Systems Protected by U.S. Patents, including 7032051, 6356140, 6650174
ATCA
TYPICAL APPLICATIO
3.3V
Rising Edge from Asserted Low
0.01F
1000
10k 10k 2.7k 2.7k 10k 10k 0.01F
V V
CC CC
ENABLE ENABLE
800
100k
LTC4307 LTC4307
MICRO-
CONTROLLER SCLIN SCLOUT SCLIN SCLOUT CARD_SCL 600
LOW
OFFSET
SDAOUT
SDAIN SDAOUT SDAIN SDAOUT CARD_SDA
400
3.3V 3.3V
SDAIN
10k 10k
200
READY READY
GND GND
4307 TA01a
0
0 100 200 300 400 500 600
100ns/DIV 4307 TA01b
BACKPLANE CARD CARD
CONNECTOR CONNECTOR
4307f
1
200mV/DIV
U
ULTC4307
ABSOLUTE AXI U RATI GS (Notes 1, 7)
V to GND ................................................. 0.3V to 6V
Storage Temperature Range
CC
SDAIN, SCLIN, SDAOUT, SCLOUT,
DFN .................................................... 65C to 125C
READY, ENABLE .......................................... 0.3V to 6V
MSOP ................................................ 65C to 150C
Maximum Sink Current (SDAIN, SCLIN, SDAOUT,
Lead Temperature (Soldering, 10 sec)
SCLOUT, READY) .............................................. 50mA
MSOP ...............................................................300C
Operating Temperature Range
LTC4307C ................................................ 0C to 70C
LTC4307I ............................................. 40C to 85C
UUW
PACKAGE/ORDER I FOR ATIO
ORDER PART ORDER PART
TOP VIEW
NUMBER NUMBER
ENABLE 1 8 V
CC TOP VIEW
LTC4307CDD LTC4307CMS8
SCLOUT 2 7 SDAOUT
ENABLE 1 8 V
CC
9
LTC4307IDD SCLOUT 2 7 SDAOUT LTC4307IMS8
SCLIN 3 6 SDAIN
SCLIN 3 6 SDAIN
GND READY
4 5
GND 4 5 READY
DD PART* MS8 PART*
MS8 PACKAGE
8-LEAD PLASTIC MSOP
DD PACKAGE MARKING MARKING
8-LEAD (3mm 3mm) PLASTIC DFN
T = 125C, = 200C/W
JMAX JA
T = 125C, = 43C/W
JMAX JA
LBTW LTBTV
EXPOSED PAD (PIN 9) CONNECTION TO GND IS OPTIONAL
LBTW LTBTV
Consult LTC Marketing for parts speci ed with wider operating temperature ranges. *The temperature grade is identi ed by a label on the shipping container.
The ELECTRICAL CHARACTERISTICS denotes the speci cations which apply over the full operating
temperature range, otherwise speci cations are at T = 25C. V = 3.3V, unless otherwise noted.
A CC
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Power Supply
V Positive Supply Voltage 2.3 5.5 V
CC
I Supply Current V = 5.5V, V = V = 0V (Note 6) 811 mA
CC CC SCLOUT SDAOUT
I Shutdown Supply Current V = 5.5V, ENABLE = GND, SDA, SCL = 5.5V 900 1200 A
SD CC
V Precharge Voltage SDA, SCL Floating 0.8 1 1.2 V
PRE
t Bus Idle Time 55 95 175 s
IDLE
V ENABLE Threshold 0.8 1.4 2 V
THR_ENABLE
I ENABLE Input Current ENABLE from 0V to V 0.1 5 A
ENABLE CC
t ENABLE Delay Off-On V = 3.3V (Figure 1) 95 s
PLH_EN CC
t ENABLE Delay On-Off V = 3.3V (Note 3) (Figure 1) 10 ns
PHL_EN CC
t READY Delay Off-On V = 3.3V (Note 3) (Figure 1) 10 ns
PLH_READY CC
t READY Delay On-Off V = 3.3V (Note 3) (Figure 1) 10 ns
PHL_READY CC
V READY Output Low Voltage I = 3mA, V = 2.3V 0.4 V
OL_READY PULLUP CC
I READY Off Leakage Current V = READY = 5.5V 0.1 5 A
OFF_READY CC
4307f
2
U WWW