LTC4300-2IMS8 Linear Technology, LTC4300-2IMS8 Datasheet - Page 11

• Manufacturer Part Number: LTC4300-2IMS8
• Description: IC BUFFER BUS HOTSWAP 2WR 8MSOP
• Manufacturer: Linear Technology
• Type: Hot-Swap Switchr

Specifications of LTC4300-2IMS8

• Applications: General Purpose, Buffer/Bus Extender
• Internal Switch(s): Yes
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

APPLICATIO S I FOR ATIO
ciated with hot swapping have settled. Owing to their small
capacitance, the SDAIN and SCLIN pins cause minimal dis-
turbance on the backplane busses when they make con-
tact with the connector.
Figure 6 shows the LTC4300-2 in a CompactPCI configu-
ration. The LTC4300-2 receives its V
of the long “early power” pins. Because this power is not
switched, add a 5 to 10 resistor between the V
of the connector and the LTC4300-2, as shown in the
figure. In addition, make sure that the V
the backplane is large compared to the 0.01 F bypass
capacitor on the card. Establishing early power V
sures that the 1V precharge voltage is present at the
SDAIN and SCLIN pins before they make contact. Connect
V
hot swap circuits. V
circuit. With the V
pins have established connection, the UVLO circuit en-
sures that the backplane and card data and clock busses
are not connected until the transients associated with hot
swapping have settled.
Figure 7 shows the LTC4300-1 in a PCI application, where
all of the pins have the same length. In this case, connect
an RC series circuit on the I/O card between V
ENABLE. An RC product of 10ms provides a filter to
prevent the LTC4300-1 from becoming activated until the
transients associated with hot swapping have settled.
Figure 8 shows the LTC4300-2 in an application where the
user has a custom connector with pins of three different
lengths available. Making V
that all other pins are firmly connected before V
receives any voltage. A filtered UVLO circuit on V
ensures that the V
LTC4300-2 connects the backplane to the card.
Repeater/Bus Extender Application
Users who wish to connect two 2-wire systems separated
by a distance can do so by connecting two LTC4300-1s
back-to-back, as shown in Figure 9. The I
allows for 400pF maximum bus capacitance, severely
limiting the length of the bus. The SMBus specification
CC2
to the output of one of the CompactPCI power supply
CC2
CC2
U
CC2
voltage powering up after all other
pin is firmly connected before the
is monitored by a filtered UVLO
U
CC2
the shortest pin ensures
W
CC
voltage from one
CC
2
C specification
bypassing on
U
CC
CC
CC
pins
and
en-
CC2
CC2
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. The strong pull-up and pull-down
impedances of the LTC4300-1 are capable of meeting rise-
and fall-time specifications for one nanofarad of capaci-
tance, thus allowing much more interconnect distance. In
this situation, the differential ground voltage between the
two systems may limit the allowed distance, because a
valid logic low voltage with respect to the ground at one
end of the system may violate the allowed V
tion with respect to the ground at the other end. In
addition, the connection circuitry offset voltages of the
back-to-back LTC4300-1s add together, directly contrib-
uting to the same problem.
Systems with Disparate Supply Voltages (LTC4300-1)
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
proper operation of the LTC4300-1, make sure that
V
5V to 3.3V Level Translator and Power Supply
Redundancy (LTC4300-2)
Systems requiring different supply voltages for the
backplane side and the card side can use the LTC4300-2,
as shown in Figure 11. The pull-up resistors on the card
side connect from SDAOUT to SCLOUT to V
on the backplane side connect from SDAIN and SCLIN to
V
2.7V to 5.5V on both V
on the voltage magnitudes of V
each other.
This application also provides power supply redundancy.
If either the V
threshold, the LTC4300-2 disconnects the backplane from
the card, so that the side that is still powered can continue
to function.
CC(BUS)
CC
. The LTC4300-2 functions for voltages ranging from
V
LTC4300-1/LTC4300-2
CC(LTC4300)
CC
or V
CC
CC
CC2
– 0.5V.
and V
line, as shown in Figure 10. For
voltage falls below its UVLO
CC
CC
CC2
voltages seen by devices
and V
. There is no constraint
CC2
with respect to
CC2
OL
sn430012 430012fs
, and those
specifica-
11