LTC4312
Pin-Selectable, 2-Channel,
2-Wire Multiplexer
with Bus Buffers
FEATURES DESCRIPTION
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1:2 Multiplexer/Switch for 2-Wire Bus The LTC 4312 is a hot-swappable 2-channel 2-wire bus
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Bidirectional Buffer for SDA and SCL Lines multiplexer that allows one upstream bus to connect to
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any combination of downstream busses or channels.
High Noise Margin with V = 0.3V
IL CC
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An individual enable pin controls each connection. The
ENABLE Pins Connect SDA and SCL Lines
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LTC4312 provides bidirectional buffering, keeping the up-
Selectable Rise Time Accelerator Current and
stream bus capacitance isolated from the downstream bus
Activation Voltage
n capacitances. The high noise margin allows the LTC4312
Level Shift 1.5V, 1.8V, 2.5V, 3.3V and 5V Busses
2
n to be interoperable with I C devices that drive a high V
Prevents SDA and SCL Corruption During Live Board
OL
(> 0.4V). The LTC4312 supports level translation between
Insertion and Removal from Backplane
n 1.5V, 1.8V, 2.5V, 3.3V and 5V busses. The hot-swappable
Stuck Bus Disconnect and Recovery
2 2
nature of the LTC4312 allows I/O card insertion into, and
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Compatible with I C, I C Fast Mode and SMBus
removal from, a live backplane without corruption of the
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4kV Human Body Model (HBM) ESD Ruggedness
data and clock busses.
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14-Lead 4mm 3mm DFN and 16-Lead MSOP
Packages
If both data and clock are not simultaneously high at
least once in 45ms and DISCEN is high, a FAULT signal is
APPLICATIONS
generated indicating a stuck bus low condition, the input
is disconnected from each enabled output channel and up
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Telecommunications Systems Including ATCA
to 16 clocks are generated on the enabled downstream
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Address Expansion
busses. A three state ACC pin enables input and output
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Level Translator
side rise time accelerators of varying strengths and sets
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Capacitance Buffers/Bus Extender
the V voltage.
IL,RISING
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Live Board Insertion
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
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PMBus
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
6356140, 6650174, 7032051, 7478286.
TYPICAL APPLICATION
3.3V 3.3V
Rising Edge from Asserted Low
with Level Translation
0.01F 0.01F
10k 10k V V 10k 10k
CC CC2
6V
C + C = 100pF
SCLOUT1 SCLOUT2
C = 50pF
SCLIN
SCLIN SCLIN SCLOUT2
5V
SDAIN SDAIN
ENABLE1 ENABLE1 SCLOUT1 SCLOUT1
ENABLE2 ENABLE2 SDAOUT1 SDAOUT1 SCLOUT1
3.3V
5V
3.3V SCLIN
LTC4312
10k 10k
10k
ACC SCLOUT2 SCLOUT2
DISCEN SDAOUT2 SDAOUT2
0V
FAULT FAULT
GND 200ns/DIV
4312 TA01b
4314 TA01a
4312f
1
1V/DIVLTC4312
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 2)
Supply Voltage Output DC Sink Currents
V , V ................................................. 0.3V to 6V FAULT ................................................................. 50mA
CC CC2
Input Voltages Operating Ambient Temperature Range
ACC, DISCEN, ENABLE1-2 ....................... 0.3V to 6V LTC4312C ................................................ 0C to 70C
Input/Output Voltages LTC4312I..............................................40C to 85C
SDAIN, SCLIN, SCLOUT1-2, Storage Temperature Range ..................65C to 150C
SDAOUT1-2, FAULT ................................. 0.3V to 6V Lead Temperature (Soldering, 10 sec)
MSOP .............................................................. 300C
PIN CONFIGURATION
TOP VIEW
TOP VIEW
V 1 14 DISCEN
CC
DISCEN 1 16 ACC
2 13
SCLOUT1 ACC
V 2 15 GND
CC
3 12
SDAOUT1 GND
SCLOUT1 3 14 NC
SDAOUT1 4 13 NC
SDAIN 4 15 11 V
CC2
SDAIN 5 12 V
CC2
SCLIN 5 10 FAULT
SCLIN 6 11 FAULT
SCLOUT2 6 9 ENABLE1
SCLOUT2 7 10 ENABLE1
SDAOUT2 7 8 ENABLE2 SDAOUT2 8 9 ENABLE2
MS PACKAGE
16-LEAD PLASTIC MSOP
DE14 PACKAGE
14-LEAD (4mm = 3mm) PLASTIC DFN
T = 150C, = 120C/W, = 21C/W
JMAX JA JC
T = 125C, = 43C/W, = 5C/W
JMAX JA JC
EXPOSED PAD (PIN #15) PCB CONNECTION TO GND IS OPTIONAL
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC4312IDE#PBF LTC4312IDE#TRPBF 4312 14-Lead (4mm 3mm) DFN 40C to 85C
LTC4312IMS#PBF LTC4312IMS#TRPBF 4312 16-Lead Plastic MSOP 40C to 85C
LTC4312CDE#PBF LTC4312CDE#TRPBF 4312 14-Lead (4mm 3mm) DFN 0C to 70C
LTC4312CMS#PBF LTC4312CMS#TRPBF 4312 16-Lead Plastic MSOP 0C to 70C
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.
Consult LTC Marketing for information on non-standard lead based nish parts.
For more information on lead free part marking, go to: