LTC4301 Linear Technology, LTC4301 Datasheet - Page 9

• Manufacturer Part Number: LTC4301
• Description: Supply Independent Hot Swappable 2-Wire Bus Buffer
• Manufacturer: Linear Technology

APPLICATIO S I FOR ATIO
filter to prevent the LTC4301 from becoming activated
until the transients associated with live insertion have
settled. Connect the capacitor between V
the resistor from CS to GND.
Repeater/Bus Extender Application
Users who wish to connect two 2-wire systems separated
by a distance can do so by connecting two LTC4301s
back-to-back as shown in Figure 6. The I
allows for 400pF maximum bus capacitance, severely
limiting the length of the bus. The SMBus specification
places no restriction on bus capacitance, but the limited
impedances of devices connected to the bus require
systems to remain small if rise- and fall-time specifica-
tions are to be met. Using the LTC4301 allows the capaci-
tance to be isolated into smaller sections, enabling the
V
SDA
SCL
V
CC2
CC
R1
10k
BACKPLANE
R2
10k
Figure 5. Inserting Multiple I/O Cards into a Live Backplane Using the LTC4301 in a PCI System
U
CONNECTOR
BACKPLANE
U
W
2
CC
C specification
and CS, and
U
R3
100k
R7
100k
0.1µF
0.1µF
system to meet rise- and fall-time requirements. In this
situation, the differential ground voltage between the two
systems may limit the allowed distance, because valid
logic low voltage with respect to the ground at one end of
the system may violate the allowed V
respect to the ground at the other end. In addition, the
connection circuitry offset voltages of the back-to-back
LTC4301s add together, directly contributing to the same
problem.
Systems with Supply Voltage Droop
In large 2-wire systems, the V
at various points in the system can differ by a few hundred
millivolts or more. This situation is well modelled by a series
resistor in the V
operation, make sure that the V
CS
SDAIN
SCLIN
CS
SDAIN
SCLIN
I/O PERIPHERAL CARD 1
I/O PERIPHERAL CARD 2
LTC4301
LTC4301
GND
GND
V
V
•
•
•
CC
CC
CC
line as shown in Figure 7. For proper
0.01µF
0.01µF
SDAOUT
SDAOUT
SCLOUT
SCLOUT
READY
READY
CC
R4
10k
R8
10k
CC(LTC4301)
voltages seen by devices
www.DataSheet4U.com
R5
10k
R9
10k
OL
specification with
LTC4301
R6
10k
R10
10k
is ≥ 2.7V.
CARD_SDA
CARD_SCL
CARD2_SDA
CARD2_SCL
4301 F05
4301fb
9