Datasheet

LTC4365
9
4365fa
For more information www.linear.com/LTC4365
operaTion
the system only if the input supply meets the user select-
able voltage window. Reverse supply protection circuits
automatically
isolate the load from negative input voltages.
During normal operation, a high voltage charge pump
applicaTions inForMaTion
The LTC4365 is an N-channel MOSFET controller that
protects a load from faulty supply connections. A basic
application circuit using the LTC4365 is shown in Figure 2
The circuit provides a low loss connection from V
IN
to
V
OUT
as long as the voltage at V
IN
is between 3.5V and
V
IN
UV
OV
SHDN
OV = 18V
UV = 3.5V
4365 F02
V
OUT
FAULT
GATE
V
IN
12V NOMINAL
V
OUT
3.5V TO 18V
Si4946
60V DUAL
GND
LTC4365
R5
100k
C
OUT
100µF
R3
1820k
R2
243k
R1
59k
+
M1
M2
Figure 1. Operational Diagram Common to Many Portable Products
18V. Voltages at V
IN
outside of the 3.5V to 18V range are
prevented from getting to the load and can be as high as
60V and as low as –40V. The circuit of Figure 2 protects
against negative voltages at V
IN
as shown. No other external
components are needed.
During normal operation, the LTC4365 provides up to
9.8V of gate enhancement to the external back-to-back
N-channel MOSFETs. This turns on the MOSFET, thus
connecting the load at V
OUT
to the supply at V
IN
.
GATE Drive
The LTC4365 turns on the external N-channel MOSFETs by
driving the GATE pin above V
OUT
. The voltage difference
between the GATE and V
OUT
pins (gate drive) is a function
of V
IN
and V
OUT
.
enhances the gate of external N-channel power MOSFETs.
Power consumption is 10µA during shutdown and 125µA
while operating. The LTC4365 integrates all these func
-
tions in tiny TSOT-23 and 3mm × 2mm DFN packages.
V
IN
UV
OV
SHDN
2.5V TO 34V
OPERATING RANGE
4365 F01
V
OUT
FAULT
GATE
GND
LTC4365
R5
R3
BATTERY
–40V TO 60V PROTECTION RANGE
AC
ADAPTOR
INPUT
OV, UV PROTECTION
THRESHOLDS SET TO
SATISFY LOAD CIRCUIT
R2
R1
M1 M2
LOAD
CIRCUIT
+
–
Figure 2. LTC4365 Protects Load from –40V
to 60V V
IN
Faults