LTC4313-1_15 Datasheet, PDF (1/20 Pages) Linear Technology – 2-Wire Bus Buffers with High Noise Margin

Features
n _{Bidirectional Buffer Increases Fanout}
n _{High Noise Margin with VIL = 0.3•VCC}
n _{Compatible with Non-Compliant I}²_{C Devices That}
Drive a High V_OL
n _{Strong (LTC4313-1) and 2.5mA (LTC4313-2)}
Rise Time Accelerator Current
n _{Level Shift 1.5V, 1.8V, 2.5V, 3.3V and 5V Busses}
n _{Prevents SDA and SCL Corruption During Live Board}
Insertion and Removal from Backplane
n _{Stuck Bus Disconnect and Recovery}
n _{Compatible with I}²_{C, I}²_{C Fast Mode and SMBus}
n _{±4kV Human Body Model ESD Ruggedness}
n _{High Impedance SDA, SCL Pins When Unpowered}
n _{8-Lead MSOP and 8-Lead (3mm × 3mm) DFN}
Packages
Applications
n _{Capacitance Buffers/Bus Extender}
n _{Live Board Insertion}
n _{Telecommunications Systems Including ATCA}
n _{Level Translation}
n _PMBus
n _Servers
LTC4313-1/LTC4313-2/
LTC4313-3
2-Wire Bus Buffers with
High Noise Margin
Description
The LTC^®4313 is a hot swappable 2-wire bus buffer
that provides bidirectional buffering while maintain-
ing a low offset voltage and high noise margin up to
0.3 • V_CC. The high noise margin allows the LTC4313 to be
interoperable with devices that drive a high V_OL (>0.4V) and
allows multiple LTC4313s to be cascaded. The LTC4313-1
and LTC4313-2 support level translation between 3.3V and
5V busses. In addition to these voltages, the LTC4313-3
also supports level translation to 1.5V, 1.8V and 2.5V.
During insertion, the SDA and SCL lines are pre-charged to
1V to minimize bus disturbances. Connection is established
between the input and output after ENABLE is asserted
high and a stop bit or bus idle condition has been detected
on the SDA and SCL pins.
If both data and clock are not simultaneously high at least
once in 45ms, the input is disconnected from the output.
Up to 16 clock pulses are subsequently generated to free
the stuck bus. Rise time accelerators (RTAs) provide pull-up
currents on SDA and SCL rising edges to meet rise time
specifications in heavily loaded systems. The RTAs are
configured as slew limited switches in the LTC4313-1 and
2.5mA current sources in the LTC4313-2. The LTC4313-3
does not have RTAs.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
Hot Swap is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners. Protected by U.S. Patents, including 6356140, 6650174,
7032051, 7478286.
Typical Application
3.3V
5V
0.01µF
2.7k 2.7k
SCL1
SDA1
V_CC
ENABLE
LTC4313-1
10k 1.3k 1.3k
SCLIN
SDAIN
READY
SCLOUT
SDAOUT
GND
4313123 TA01a
READY
SCL2
SDA2
400kHz Operation
R_{BUS_IN} = 2.7kΩ, C_{BUS_IN} = 50pF
R_{BUS_OUT} = 1.3kΩ, C_{BUS_OUT} = 100pF
SCLOUT
SCLIN
500ns/DIV
4313123 TA01b
4313123f
1