LTC4308
Low Voltage, Level Shifting
Hot Swappable 2-Wire Bus
Buffer with Stuck Bus Recovery
FEATURES DESCRIPTION
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Optimized for Low Voltage Systems Down to 0.9V The LTC 4308 hot swappable, 2-wire bus buffer allows
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Bidirectional Buffer with Stuck Bus Recovery I/O card insertion into a live backplane without corrup-
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200mV Offset In-Out/+300mV Offset Out-In tion of the data and clock busses. The LTC4308 provides
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30ms Stuck Bus Timeout bidirectional buffering, keeping the backplane and card
2
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Compatible with Non-Compliant V I C Devices capacitances isolated. Negative offset from output to
OL
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Prevents SDA and SCL Corruption During Live input allows communication between output bus devices
Board Insertion and Removal from Backplane with high V and devices on the low voltage input side,
OL
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6kV Human Body Model (HBM) ESD Protection where bus supplies can be as low as 0.9V. If SDAOUT or
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Isolates Input SDA and SCL Lines from Output SCLOUT are low for 30ms, the LTC4308 will automati-
2 2
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Compatible with I C, I C Fast Mode and SMBus cally break the Input-Output connection. At this time the
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READY Open-Drain Output LTC4308 automatically generates up to 16 clock pulses
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1V Precharge on SDAOUT and SCLOUT Lines on SCLOUT in an attempt to free the bus. A connection
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Small 8-Lead (3mm 3mm 0.75mm) DFN and will resume if the stuck bus is cleared.
8-Lead MSOP Packages
During insertion, the SDAOUT and SCLOUT lines are pre-
charged to 1V to minimize bus disturbances. When driven
APPLICATIONS
high, the ENABLE input allows the LTC4308 to connect after
a stop bit or bus idle condition. Driving ENABLE low breaks
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Live Board Insertion
the connection between SDAIN and SDAOUT, SCLIN and
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Servers
SCLOUT. READY is an open-drain output which indicates
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Capacitance Buffer/Bus Extender
that the backplane and card sides are connected.
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RAID Systems
n L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. Hot Swap
ATCA
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.
TYPICAL APPLICATION
The LTC4308 in a 1.2V
1.2V to 5V Level Shifting
Microcontroller Application
SDAOUT
5V
1.2V
0.01F 2V/DIV
CH1
2.7k 2.7k 10k 2.7k 2.7k
V
CC
LTC4308
SDAIN
SCLIN SCLOUT CARD_SCL
MICRO-
CONTROLLER
0.5V/DIV
SDAIN SDAOUT CARD_SDA
CH2
4308 TA01a
ENABLE
READY READY
GND
1s/DIV
4308 TA01b
4308f
1LTC4308
ABSOLUTE MAXIMUM RATINGS (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
LTC4308C ................................................ 0C to 70C
LTC4308I.............................................. 40C to 85C
PIN CONFIGURATION
TOP VIEW
TOP VIEW
ENABLE 1 8 V
CC
ENABLE 1 8 V
CC
SCLOUT 2 7 SDAOUT
9 SCLOUT 2 7 SDAOUT
SCLIN 3 6 SDAIN
6 SDAIN
SCLIN 3
GND 4 5 READY
GND 4 5 READY
MS8 PACKAGE
8-LEAD PLASTIC MSOP
DD PACKAGE
8-LEAD (3mm 3mm) PLASTIC DFN T = 125C, = 200C/W
JMAX JA
T = 125C, = 43C/W
JMAX JA
EXPOSED PAD (PIN 9) CONNECTION TO GROUND IS OPTIONAL
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC4308CDD#PBF LTC4308CDD#TRPBF LBTT 8-Lead (3mm 3mm) Plastic DFN 0C to 70C
LTC4308IDD#PBF LTC4308IDD#TRPBF LBTT 8-Lead (3mm 3mm) Plastic DFN 40C to 85C
LTC4308CMS8#PBF LTC4308CMS8#TRPBF LTBTS 8-Lead Plastic MSOP 0C to 70C
LTC4308IMS8#PBF LTC4308IMS8#TRPBF LTBTS 8-Lead Plastic MSOP 40C to 85C
Consult LTC Marketing for parts speci ed with wider operating temperature ranges. *Temperature grades are identi ed by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based nish parts.
For more information on lead free part marking, go to: