Datasheet

LTC4365
8
4365fa
For more information www.linear.com/LTC4365
block DiagraM
V
IN
–40V TO 60V
5V INTERNAL
SUPPLY
6.5V INTERNAL
SUPPLY
LDO
2.2V
UVLO
0.5V
GND
25mV
HYSTERESIS
4365 BD
I
GATE
REVERSE
PROTECTION
CLOSES SWITCH
WHEN V
IN
IS NEGATIVE
ENABLE
GATE PULLDOWN
FAULT
OFF
TURN
OFF
50mA 90µA
SHDN
SHDN
GATE
CHARGE
PUMP
f = 400kHz
V
OUT
UV
OV
–
+
DELAY TIMERS
LOGIC
–
+
–
+
FAULT
GATE
Many of today’s electronic systems get their power from
external sources such as wall wart adapters, batteries and
custom power supplies. A typical supply arrangement for
a portable product is shown by the operational diagram
in Figure 1. Power is supplied by an AC adaptor or, if the
plug is withdrawn, by a removable battery. Trouble arises
when any of the following occurs:
• The battery is installed backwards
• An AC adaptor of opposite polarity is attached
• An AC adaptor of excessive voltage is attached
• The battery is discharged below a safe level
This can lead to supply voltages that are too high, too
low, or even negative. If these power sources are applied
directly to the electronic systems, the systems could be
subject to damage. The LTC4365 is an input voltage fault
protection N-channel MOSFET controller. The part isolates
an input supply from its load to protect the load from
unexpected supply voltage conditions, while providing a
low loss path for qualified power.
To protect electronic systems from improperly connected
power supplies, system designers will often add discrete
diodes, transistors and high voltage comparators. The high
voltage comparators enable system power only if the input
supply falls within a
desired voltage window. A Schottky
diode
or P-channel MOSFET typically added in series with
the supply protects against reverse supply connections.
The LTC4365 provides accurate overvoltage and under
-
voltage comparators
to ensure that power is applied to
operaTion