LTC4310CDD-2-TRPBF View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
'LTC4310CDD-2-TRPBF' PDF : 20 Pages View PDF
Applications Information
LTC4310-1/LTC4310-2
BACKPLANE
CONNECTOR
BACKPLANE
5V
R1 R2 R3
2k 2k 10k
SDA
SCL CBUS = 400pF
READY
EN
CARD
CONNECTOR
I/O PERIPHERAL CARD
C6
C7
0.01µF 0.01µF
VCC
TXP
LTC4310-1
SDA TXN
SCL
READY RXP
EN
RXN
R7
100k
GND
C1
C2
C3
C4
C5
VCC
RXP
LTC4310-1
RXN SDA
SCL
TXP READY
EN
TXN
GND
3.3V
R4 R5 R6
6.8k 6.8k 10k
CBUS = 50pF
SDA2
SCL2
READY2
EN2
C1 TO C5 = 47pF, 100V
431012 F10
Figure 10. The LTC4310-1 in an I2C Hot-Swapping Application
Figure 10 shows the LTC4310-1 in a two-wire bus Hot Swap
application. Using a staggered connector, make EN the
shortest length pin to ensure that the transients associated
with hot swapping have settled before the LTC4310-1 can
be enabled. After connection is complete, a master on the
backplane may drive EN high to bring the LTC4310-1 out
of shutdown mode and into normal operation. Due to its
STOP bit and bus idle detection circuitry, the LTC4310-1’s
driver circuitry is not activated until transactions on both
buses are complete.
LTC4310 Compatibility with Other LTC Bus Buffers
The LTC4310 cannot be used on the same I2C bus with the
LTC4300A-1, LTC4303 or LTC4307. During rising edges,
the rise time accelerators of these buffers turn on before
the LTC4310 disables its rise rate regulation circuitry,
resulting in nonmonotonic bus edges.
The LTC4310-1 is compatible with the LTC4301 and
LTC4301L. It is also compatible with the LTC4302, LTC4304,
LTC4305 and LTC4306, provided that the rise time accelera-
tors of these buffers are permanently disabled. All of the
previously mentioned buffers are incompatible with the
LTC4310-2 because the compensation networks of these
buffers cause the bus to rise more slowly than (0.35 •
VCC)/300ns, therefore the LTC4310-2 would not be able
to control the bus rise rate.
LTC4310-1 Compatibility with LTC4310-2
In a typical application such as shown in Figure 1, an
LTC4310-1 can be used on one bus and an LTC4310-2 can
be used on the other, provided that the bus pull-up resis-
tors connected to the LTC4310-1 meet the requirements
of Figure 2, and the bus pull-up resistors connected to the
LTC4310-2 meet the requirements of Figure 3. However,
the bus switching frequency is limited by the rise rate
regulation circuitry of the LTC4310-1. In addition, significant
skew is introduced on the rising edges due to the large
difference in the controlled rise rates of the two buses. For
this reason, it is recommended to use two LTC4310-1’s
in SMBus and standard mode I2C applications and to use
two LTC4310-2’s in fast mode I2C applications.
The LTC4310-1 cannot be used on the same physical I2C
bus with the LTC4310-2, because the LTC4310-1’s rise
rate regulation circuitry controls the bus rise rate to (0.35
• VCC)/900ns, therefore the LTC4310-2 would not be able
to control the bus rise rate.
431012fa
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