LTC4302-1/LTC4302-2
Addressable
2-Wire Bus Buffers
FEATURES DESCRIPTIO
2
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Bidirectional Buffer for SDA and SCL Lines The LTC 4302-1/LTC4302-2 addressable I C bus and
Increases Fanout SMBus compatible bus buffers allow a peripheral board
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Connect SDA and SCL Lines with 2-Wire Bus to be inserted and removed from a live backplane without
Commands corruption of the bus. The LTC4302-1/LTC4302-2 main-
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Prevents SDA and SCL Corruption During Live Board tain electrical isolation between the backplane and periph-
Insertion and Removal from Backplane eral board until their V supply is valid and a master
CC
TM
2 2
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Compatible with I C Standard Mode, I C Fast device on the backplane side addresses the LTC4302-1/
Mode and SMBus Standards LTC4302-2 and commands them to connect. The
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Rise Time Accelerators on SDA, SCL Lines LTC4302-1/LTC4302-2s ADDRESS pin provides 32 pos-
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1V Precharge on SDA and SCL Lines sible addresses set by an external resistive divider be-
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32 Unique Addresses from a Single ADDRESS Pin tween V and GND. The LTC4302-1/LTC4302-2 work
CC
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Two General Purpose Inputs-Outputs (LTC4302-1) with supply voltages ranging from 2.7V to 5.5V. The SDA
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Translates Between 5V and 3.3V Systems and SCL inputs and outputs do not load the bus lines when
(LTC4302-2) V is low.
CC
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Small 10-Pin MSOP Package
Rise time accelerator circuitry* allows for heavier capaci-
tive bus loading while still meeting system timing require-
U
ments. During insertion, the SDA and SCL lines are
APPLICATIO S
precharged to 1V to minimize bus disturbances. Two
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Live Board Insertion
general purpose input/output pins (GPIOs) on the
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5V/3.3V Level Translator
LTC4302-1 can be configured as inputs, open-drain out-
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Servers
puts or push-pull outputs. The LTC4302-2 option replaces
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Capacitance Buffer/Bus Extender
one GPIO pin with a second supply voltage pin V ,
CC2
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Nested Addressing
providing level shifting between systems with different
, LTC and LT are registered trademarks of Linear Technology Corporation.
supply voltages. The LTC4302-1/LTC4302-2 are available
2
I C is a trademark of Philips Electronics N.V.
*U.S. Patent No. 6,650,174
in a 10-pin MSOP package.
TYPICAL APPLICATIO
Input-Output Connection t
PLH
2.7V
to
C1
5.5V
R3 R4 R1 R5 R6 R7 R8 R9
0.01F
V
10k CC
10k 10k 1870 10k 10k 1k 1k
OUTPUT INPUT
LTC4302-1
SDA CARD SDA
SIDE SIDE
SDAIN SDAOUT
SCL
CARD SCL 50pF 150pF
SCLIN SCLOUT
CONN
LED
ADDRESS GPIO2
LED
R2
GPIO1
2000
4203 TA01a
GND
4032 F10
0.1m s/DIV
sn430212 430212fs
1
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ULTC4302-1/LTC4302-2
ABSOLUTE AXI U RATI GS
(Note 1)
V to GND ................................................. 0.3V to 7V Operating Temperature Range
CC
SDAIN, SCLIN, SDAOUT, SCLOUT, LTC4302C-1/LTC4302C-2 ...................... 0 C to 70 C
GPIO1, CONN, GPIO2 (LTC4302-1), LTC4302I-1/LTC4302I-2 .................... 40 C to 85 C
V (LTC4302-2)........................................ 0.3V to 7V Storage Temperature Range ................. 65 C to 125 C
CC2
ADDRESS ....................................... 0.3V to V + 0.3V Lead Temperature (Soldering, 10 sec).................. 300 C
CC
UUW
PACKAGE/ORDER I FOR ATIO
ORDER PART
ORDER PART
TOP VIEW TOP VIEW
NUMBER
NUMBER
SDAIN 1 10 SDAOUT SDAIN 1 10 SDAOUT
SCLIN 2 9 SCLOUT SCLIN 2 9 SCLOUT
LTC4302CMS-1 LTC4302CMS-2
CONN 3 8 V CONN 3 8 V
CC CC
ADDRESS 4 7 GPIO2 LTC4302IMS-1 ADDRESS 4 7 V LTC4302IMS-2
CC2
GND 5 6 GPIO1 GND 5 6 GPIO1
MS PART MARKING
MS PART MARKING
MS PACKAGE MS PACKAGE
10-LEAD PLASTIC MSOP 10-LEAD PLASTIC MSOP
LTYF LTABY
T = 125 C, q = 130 C/W T = 125 C, q = 130 C/W
JMAX JA JMAX JA
LTYG LTABZ
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25 C.
A
V = 2.7V to 5.5V (LTC4302-1), V = V = 2.7V to 5.5V (LTC4302-2) unless otherwise noted.
CC CC CC2
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Power Supply/Start-Up
V Positive Supply Voltage LTC4302-1 l 2.7 5.5 V
CC
V Card Side Supply Voltage LTC4302-2 l 2.7 5.5 V
CC2
I Supply Current V = 0V, V = 5.5V (Note 2) LTC4302-1 l 5.9 8 mA
CC SDAIN CC
I V Supply Current V = 0V, V = V = 5.5V l 3.4 5 mA
VCC CC SDAIN CC CC2
(Note 2) LTC4302-2
I V Supply Current V = 0V, V = V = 5.5V l 2.3 4 mA
VCC2 CC2 SDAIN CC CC2
(Note 2) LTC4302-2
V UVLO Upper Threshold V Rising l 2.5 2.7 V
UVLOU CC
V UVLO Lower Threshold V Falling 2.35 V
UVLOL CC
V V UVLO Upper Threshold LTC4302-2 l 2.5 2.7 V
UVLO2U CC2
V V UVLO Lower Threshold LTC4302-2 2.35 V
UVLO2L CC2
V Precharge Voltage SDA, SCL Floating l 0.8 1 1.2 V
PRE
V CONN Threshold Voltage l 0.8 1.5 2.2 V
THCONN
t CONN Delay, On-Off 60 ns
PHL
t CONN Delay, Off-On 20 ns
PLH
sn430212 430212fs
2
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