LTC4244 LINER [Linear Technology], LTC4244 Datasheet - Page 7

• Manufacturer Part Number: LTC4244
• Description: Rugged, CompactPCI Bus Hot Swap Controllers
• Manufacturer: LINER [Linear Technology]

PI FU CTIO S
12V
nected between 12V
limit. An undervoltage lockout circuit prevents the switches
from turning on while the 12V
12V
node.
V
nected between V
limit. An undervoltage lockout circuit prevents the switches
from turning on while the V
–9.25V. The V
abled for the LTC4244-1.
5V
pull low until the 5V
active pull-down discharges 5V
power switches are turned off.
TIMER (Pin 4): Current Fault Inhibit Timing Input and
Auxiliary V
When the LTC4244 is turned on, a 21 A pull-up current
source is connected to TIMER. Current limit faults will be
ignored until the voltage at the TIMER pin rises to within
1.6V of 12V
ing up, the TIMER capacitor serves as an auxiliary charge
reservoir for V
momentarily drops below the undervoltage lockout thresh-
old voltage. When the LTC4244 is turned off (OFF/ON >
2V), the TIMER pin is pulled down to GND. After the TIMER
pin voltage drops to within 0.8V of GND, the TIMER latch
is reset and the part is ready for another power cycle.
EEIN
OUT
U
IN
IN
(Pin 2): –12V Supply Input. A 1 switch is con-
also provides power to the LTC4244’s internal V
(Pin 1): 12V Supply Input. A 0.5 switch is con-
(Pin 3): 5V Output Sense. The PWRGD pin will not
U
CC
IN
. Connect a capacitor from TIMER to GND.
. After the TIMER pin has completed ramp-
EEIN
CC
EEIN
OUT
undervoltage lockout function is dis-
in the event the 12V
IN
U
and 12V
and V
pin voltage exceeds 4.61V. A 200
EEIN
EEOUT
IN
OUT
pin voltage is less than 9V.
pin voltage is greater than
OUT
with a foldback current
with a foldback current
to ground when the
IN
pin voltage
CC
OFF/ON (Pin 5): Digital Input. Connect the CPCI BD_SEL#
signal to the OFF/ON pin. When the OFF/ON pin is pulled
low, the GATE pin is pulled high by a 67 A current source
and the internal 12V and –12V switches are turned on.
When the OFF/ON pin is pulled high, the GATE pin will be
pulled to ground by a 60 A current source and the 12V and
–12V switches turn off.
FAULT (Pin 6): Open-Drain Digital I/O. FAULT is pulled low
when a current limit fault is detected. Current limit faults
are ignored until the voltage at the TIMER pin is within 1.6V
of 12V
pull low and the LTC4244 latches off in the event of an
overcurrent fault. The part will remain in the latched off
state until the OFF/ON pin is cycled high then low. Forcing
the FAULT pin low with an external pull-down will cause
the part to latch into the off state after a 25 s deglitching
time.
PWRGD (Pin 7): Open-Drain Digital Power Good Output.
Connect the CPCI HEALTHY# signal to the PWRGD pin.
PWRGD remains low while V
2.9V, V
the supplies falls below its power good threshold voltage,
PWRGD will go high after a 14 s deglitching time.
GND (Pin 8): Device Ground.
RESETIN (Pin 9): Digital Input. Connect the CPCI PCI_RST#
signal to the RESETIN pin. Pulling the RESETIN pin low will
cause RESETOUT to pull low. RESETOUT will also pull low
when PWRGD is high.
IN
5VOUT
. Once the TIMER cycle is complete, FAULT will
4.61V, and V
LTC4244/LTC4244-1
EEOUT
12VOUT
–11.1V. When any of
11.1V, V
3.3VOUT
42441f
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