LTC4306 Datasheet, PDF (1/20 Pages) Linear Technology – 4-Channel, 2-Wire Bus Multiplexer with Capacitance Buffering

LTC4306
4-Channel,
2-Wire Bus Multiplexer with
Capacitance Buffering
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 I}²_{C 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}
U
APPLICATIO S
■ _{Nested Addressing}
■ _{5V/3.3V Level Translator}
■ _{Capacitance Buffer/Bus Extender}
DESCRIPTIO
The LTC^®4306 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.
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners. Patent pending.
TYPICAL APPLICATIO
A Level Shifting and Nested Addressing Application
2.5V
3.3V
MICRO-
CONTROLLER
10k 10k 10k
0.01µF
10k 10k 10k
V_CC
SCLIN SCL1
SDAIN SDA1
ALERT ALERT1
LTC4306
•
•
•
SFP
MODULE 1
ADDRESS = 1111 000
5V
10k 10k 10k
ADR2 SCL4
ADR1 SDA4
ADR0 ALERT4
GND
4306 TA01a
ADDRESS = 1000 100
SFP
MODULE 4
ADDRESS = 1111 000
V_CC = 3.3V
SCLIN
2V/DIV
SCL1
2V/DIV
SCL4
2V/DIV
I²C Bus Waveforms
VBACK = 2.5V
VCARD1 = 3.3V
VCARD4 = 5V
500ns/DIV
4306 TA01b
4306f
1