DESCRIPTION
The LTC4306 is a 4-channel, 2-wire bus multiplexer with
bus buffers to provide capacitive isolation between the
upstream bus and downstream buses. Through software
control, the LTC4306 connects the upstream 2-wire bus to
any desired combination of downstream buses. Each
channel can be pulled up to a supply voltage ranging from
2.2V to 5.5V, independent of the LTC4306 supply voltage.
The downstream channels are also provided with
ALERT1-ALERT4 inputs for fault reporting.
Programmable timeout circuitry disconnects the down-
stream buses if the bus is stuck low. When activated, rise
time accelerators source currents into the 2-wire bus pins
to reduce rise time. Driving the ENABLE pin low restores
all features to their default states. Three address pins
provide 27 distinct addresses.
The LTC4306 is available in 24-lead QFN (4mm×5mm)
and SSOP packages.
FEATURES
1:4 2-Wire Multiplexer/Switch
Connect SDA and SCL Lines with 2-Wire Bus
Commands
Supply Independent Bidirectional Buffer for SDA
and SCL Lines Increases Fan-Out
Programmable Disconnect from Stuck Bus
Compatible with IC and SMBus Standards
Rise Time Accelerator Circuitry
SMBus Compatible ALERT Response Protocol
Two General Purpose Inputs-Outputs
Prevents SDA and SCL Corruption During Live Board
Insertion and Removal from Backplane
±10kV Human Body Model ESD Ruggedness
24-Lead QFN (4mm×5mm) and SSOP Packages.
APPLICATIONS
Nested Addressing
5V/3.3V Level Translator
Capacitance Buffer/Bus Extender
TYPICAL APPLICATION
A Level Shifting and Nested Addressing Application
I 2 C Bus Waveforms
UFD PACKAGE
GN PACKAGE
Example of Unacceptable Level Shifting
A Level Shifting Circuit
P/N Package
LTC4306CUFD QFN24
LTC4306IUFD QFN24
LTC4306CGN SSOP24
LTC4306IGN SSOP24