LTC4300A-3_15 Datasheet, PDF (1/14 Pages) Linear Technology – Level-Shifting Hot Swappable 2-Wire Bus Buffer with Enable

Features
n _{Bidirectional Buffer* for SDA and SCL Lines}
Increases Fanout
n _{Prevents SDA and SCL Corruption During Live}
Board Insertion and Removal From Backplane
n _{Logic Threshold ENABLE Input}
n _{Isolates Input SDA and SCL Lines From Output}
n _{Compatible with I}²_{C, I}²_{C Fast Mode and SMBus}
Standards (Up to 400kHz Operation)
n _{1V Precharge on all SDA and SCL Lines}
n _{Supports Clock Stretching, Arbitration and}
Synchronization
■ _{5V to 3.3V Level Translation}
■ _{High Impedance SDA, SCL Pins for VCC = 0V,}
V_CC2 = 0V
■ _{Small 8-Lead DFN and MSOP Packages}
Applications
n _{Hot Board Insertion}
n _Servers
n _{Capacitance Buffer/Bus Extender}
n _{Desktop Computer}
LTC4300A-3
Level-Shifting
Hot Swappable 2-Wire
Bus Buffer with Enable
Description
The LTC^®4300A-3 hot swappable 2-wire bus buffer allows
I/O card insertion into a live backplane without corruption
of the data and clock busses. When the connection is made,
the LTC4300A-3 provides bidirectional buffering, keeping
the backplane and card capacitances isolated. Rise time
accelerator circuitry allows the use of weaker DC pull-up
currents while still meeting rise time requirements. During
insertion, the SDA and SCL lines are precharged to 1V to
minimize bus disturbances.
The LTC4300A-3 provides level translation between
3.3V and 5V supplies. The backplane and card can both
be powered with supplies ranging from 2.7V to 5.5V.
The LTC4300A-3 also incorporates a CMOS threshold
ENABLE pin which forces the part into a low current mode
and isolates the card from the backplane. When driven to
V_CC, the ENABLE pin sets normal operation.
The LTC4300A-3 is available in the MSOP and 3mm × 3mm
DFN packages.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
Hot Swap and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks
are the property of their respective owners. *Patent pending.
Typical Application
V_CC
3.3V
SCLIN
10k 10k ₈
3
0.01µF
1
10k
2
V_CC2
0.01µF
10k
SCLOUT
6
SDAIN
7
SDAOUT
OFF ON
5
LTC4300A-3
ENABLE _GND
4
4300a3 TA01
Input–Output Connection
OUTPUT
SIDE
50pF
0.5V/DIV
INPUT
SIDE
150pF
200ns/DIV
4300a3 TA01b
4300a3fa
1