Datasheet

LTC4365
7
Rev. B
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PIN FUNCTIONS
Exposed Pad: Connect to device ground.
FAULT: Fault Indication Output. This high voltage open drain
output is pulled low if UV is below its monitor threshold,
if OV is above its monitor threshold, if SHDN is low, or if
V
IN
has not risen above V
IN(UVLO)
.
GATE: Gate Drive Output for External N-channel MOSFETs.
An internal charge pump provides 20µA of pull-up current
and up to 9.8V of enhancement to the gate of an external
N-channel MOSFET.
When turned off, GATE is pulled just below the lower of
V
IN
or V
OUT
. When V
IN
goes negative, GATE is automati-
cally connected to V
IN
.
GND: Device Ground.
OV: Overvoltage Comparator Input. Connect this pin to an
external resistive divider to set the desired V
IN
overvoltage
fault threshold. The OV input connects to an accurate, fast
(1µs) comparator with a 0.5V rising threshold and 25mV
of hysteresis. When OV rises above its threshold, a 50mA
current sink pulls down on the GATE output. When OV
falls back below 0.475V, and after a 36ms recovery delay
waiting period (1ms for LTC4365-1), the GATE charge
pump is enabled. The low leakage current
of the
OV input
allows the use of large valued resistors for the external
resistive divider. Connect to GND if unused.
SHDN: Shutdown Control Input. SHDN high enables the
GATE charge pump which in turn enhances the gate of an
external N-channel MOSFET. A low on SHDN generates a
pull down on the GATE output with a 90µA current sink and
places the LTC4365 in low current mode (10µA). If unused,
connect to V
IN
. If V
IN
goes below ground, or if V
IN
rings
to 60V, use a current limiting resistor of at least 100k.
UV: Undervoltage Comparator Input. Connect this pin to an
external resistive divider to set the desired V
IN
undervolt-
age fault
threshold. The UV input connects to an accurate,
fast (1µs) comparator with a 0.5V falling threshold and
25mV of hysteresis. When UV falls below its threshold, a
50mA current sink pulls down on the GATE output. When
UV rises back above 0.525V, and after a 36ms recovery
delay waiting period (1ms for LTC4365-1), the GATE
charge pump is enabled. The low leakage current of the
UV input allows the use of large valued resistors for the
external resistive divider. If
unused
, connect to V
IN
. While
connected to V
IN
, if V
IN
goes below ground, or if V
IN
rings
to 60V, use a current limiting resistor of at least 100k.
V
IN
: Power Supply Input. Maximum protection range:
–40V to 60V. Operating range: 2.5V to 34V.
V
OUT
: Output Voltage Sense Input. This pin senses the volt-
age at
the output side of the external N-channel MOSFET.
The GATE charge pump voltage is referenced to V
OUT
. It
is used as the charge pump input when V
OUT
is greater
than approximately 6.5V.
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