LTC4355 LINER [Linear Technology], LTC4355 Datasheet - Page 5

• Manufacturer Part Number: LTC4355
• Description: Positive High Voltage Ideal Diode-OR with Input Supply and Fuse Monitors
• Manufacturer: LINER [Linear Technology]

pin FuncTions
EXPOSED PAD (Pin 15, DE Package Only): Exposed pad
may be left open or connected to GND.
FUSEFLTx (Pins 11,12/13,14): Fuse Fault Outputs.
Open-drain output that pulls to GND when V
indicating that the fuse has blown open. Otherwise, this
output is high-impedance. Connect to GND if unused.
GATEx (Pins 2,4/2,6): Gate Drive Outputs. The GATE
pins pull high, enhancing the N-channel MOSFET when
the load current creates more than 25mV of voltage drop
across the MOSFET. When the load current is small,
the gates are actively driven to maintain 25mV across
the MOSFET. If the reverse current develops more than
–25mV of voltage drop across a MOSFET, a fast pulldown
circuit quickly connects the GATE pin to the IN pin, turning
off the MOSFET. Limit the capacitance between the GATE
and IN pins to less than 0.1µF.
GND (7/9): Device Ground.
INx (Pins 1,5/1,7): Input Voltages and GATE Fast Pulldown
Returns. The IN pins are the anodes of the ideal diodes
and connect to the sources of the N-channel MOSFETs.
The voltages sensed at these pins are used to control the
source-drain voltages across the MOSFETs and are used
by the fault detection circuits that drive the PWRFLT,
FUSEFLT, and VDSFLT pins. The GATE fast pulldown cur-
rent is returned through the IN pins. Connect these pins
as close to the MOSFET sources as possible. Connect to
OUT if unused.
MONx (Pins 9,14/11,16): Input Supply Monitors. These
pins are used to sense the input supply voltages. Connect
these pins to external resistive dividers between the input
(DE/S Packages)
INx
< 3.5V,
supplies and GND. If V
pin pulls to GND. Connect to GND if unused.
OUT (Pin 3/4): Drain Voltage Sense and Positive Sup-
ply Input. OUT is the diode-OR output of IN1 and IN2. It
connects to the common drain connection of the N-chan-
nel MOSFETs. The voltage sensed at this pin is used to
control the source-drain voltages across the MOSFETs
and is used by the fault detection circuits that drive the
PWRFLT and VDSFLT pins. The LTC4355 is powered from
the OUT pin.
PWRFLTx (Pins 10,13/12,15): Power Fault Outputs.
Open-drain output that pulls to GND when V
below 1.23V or the forward voltage across the MOSFET
exceeds DV
the forward voltage across the MOSFET is less than
DV
if unused.
SET (Pin 8/10): DV
put. Tying SET to GND, to a 100kW resistor connected
to GND, or leaving SET open configures the DV
forward voltage fault threshold to 250mV, 500mV, or 1.5V
respectively. When the voltage across a MOSFET exceeds
DV
pins pull to GND.
VDSFLT (Pin 6, DE Package Only): MOSFET Fault Output.
Open-drain output that pulls to GND when the forward volt-
age across either MOSFET exceeds DV
or PWRFLT2 also pulls low to indicate which MOSFET’s
forward voltage drop exceeds DV
pin is high-impedance. Connect to GND if unused.
SD(FLT)
SD(FLT)
, PWRFLTx is high-impedance. Connect to GND
, the VSDFLT pin and at least one of the PWRFLT
SD(FLT)
. When V
SD(FLT)
MONx
falls below 1.23V, the PWRFLTx
Threshold Configuration In-
MONx
SD(FLT)
is above 1.23V and
SD(FLT)
LTC4355
. Otherwise, this
. PWRFLT1
MONx
SD(FLT)
falls
4355fa