LTC4302CMS-2 Addressable 2 Wire Bus Buffers

DESCRIPTION

The LTC4302-1/LTC4302-2 addressable IC bus and
SMBus compatible bus buffers allow a peripheral board
to be inserted and removed from a live backplane without
corruption of the bus. The LTC4302-1/LTC4302-2 main-
tain electrical isolation between the backplane and periph-
eral board until their VCC supply is valid and a master
device on the backplane side addresses the LTC4302-1/
LTC4302-2 and commands them to connect. The
LTC4302-1/LTC4302-2¡¯s ADDRESS pin provides 32 pos-
sible addresses set by an external resistive divider be-
tween VCC and GND. The LTC4302-1/LTC4302-2 work
with supply voltages ranging from 2.7V to 5.5V. The SDA
and SCL inputs and outputs do not load the bus lines when
VCC is low.
Rise time accelerator circuitry* allows for heavier capaci-
tive bus loading while still meeting system timing require-
ments. During insertion, the SDA and SCL lines are
precharged to 1V to minimize bus disturbances. Two
general purpose input/output pins (GPIOs) on the
LTC4302-1 can be configured as inputs, open-drain out-
puts or push-pull outputs. The LTC4302-2 option replaces
one GPIO pin with a second supply voltage pin VCC2,
providing level shifting between systems with different
supply voltages. The LTC4302-1/LTC4302-2 are available
in a 10-pin MSOP package.

FEATURES

Bidirectional Buffer for SDA and SCL Lines
Increases Fanout
Connect SDA and SCL Lines with 2-Wire Bus
Commands
Prevents SDA and SCL Corruption During Live Board
Insertion and Removal from Backplane
Compatible with IC Standard Mode, IC Fast
Mode and SMBus Standards
Rise Time Accelerators on SDA, SCL Lines
1V Precharge on SDA and SCL Lines
32 Unique Addresses from a Single ADDRESS Pin
Two General Purpose Inputs-Outputs (LTC4302-1)
Translates Between 5V and 3.3V Systems
(LTC4302-2)
Small 10-Pin MSOP Package.

APPLICATIONS

Live Board Insertion
5V/3.3V Level Translator
Servers
Capacitance Buffer/Bus Extender
Nested Addressing

TYPICAL APPLICATION

Input-Output Connection PLH

MS PACKAGE

MS PACKAGE

Address Compare Circuitry

P/N                            Package

LTC4302CMS-2        MSOP-10       

LTC4302IMS-2        MSOP-10          

LTC4302CMS-1        MSOP-10    

LTC4302IMS-1        MSOP-10