LT4356MP-1 Linear Technology Corporation, LT4356MP-1 Datasheet - Page 6

• Manufacturer Part Number: LT4356MP-1
• Description: Surge Stopper
• Manufacturer: Linear Technology Corporation

Specifi cations are at V
LT4356MP-1/LT4356MP-2
TYPICAL PERFORMANCE CHARACTERISTICS
6
PIN FUNCTIONS
A
iary amplifi er. It is capable of sinking up to 2mA from 80V.
The negative input of the amplifi er is internally connected
to a 1.25V reference.
EN: Open-Collector Enable Output. The EN pin goes high
impedance when the voltage at the OUT pin is above (V
– 0.7V), indicating the external MOSFET is fully on. The
state of the pin is latched until the OUT pin voltage resets
at below 0.5V and goes back up above 2V. The internal
NPN is capable of sinking up to 3mA of current from 80V
to drive an LED or opto-coupler.
Exposed Pad: Exposed pad may be left open or connected
to device ground (GND).
FB: Voltage Regulator Feedback Input. Connect this pin
to the center tap of the output resistive divider connected
between the OUT pin and ground. During an overvoltage
condition, the GATE pin is servoed to maintain a 1.25V
threshold at the FB pin. This pin is clamped internally to
7V. Tie to GND to disable the OV clamp.
FLT: Open-Collector Fault Output. This pin pulls low
after the voltage at the TMR pin has reached the fault
threshold of 1.25V. It indicates the pass transistor is
about to turn off because either the supply voltage has
stayed at an elevated level for an extended period of
OUT
500
400
300
200
100
0
: Amplifi er Output. Open collector output of the auxil-
–50
Overvoltage Turn-Off Time
vs Temperature
–25
0
TEMPERATURE (°C)
OVERVOLTAGE CONDITION
V
25
FB
CC
= 1.5V
= 12V, T
50
75
A
= 25°C unless otherwise noted.
4356mp12 G19
100
125
4.0
3.5
3.0
2.5
2.0
1.5
1.0
–50
Overcurrent Turn-Off Time
vs Temperature
–25
0
CC
TEMPERATURE (°C)
OVERCURRENT CONDITION
ΔV
25
SNS
time (voltage fault) or the device is in an overcurrent
condition (current fault). The internal NPN is capable of
sinking up to 3mA of current from 80V to drive an LED or
opto-coupler.
GATE: N-channel MOSFET Gate Drive Output. The GATE pin
is pulled up by an internal charge pump current source and
clamped to 14V above the OUT pin. Both voltage and cur-
rent amplifi ers control the GATE pin to regulate the output
voltage and limit the current through the MOSFET.
GND: Device Ground.
IN
can be used as a level detection comparator with external
hysteresis or linear regulator controlling an external PNP
transistor. This pin is clamped internally to 7V. Connect
to ground if unused.
OUT: Output Voltage Sense Input. This pin senses the
voltage at the source of the N-channel MOSFET and sets
the fault timer current. When the OUT pin voltage reaches
0.7V away from V
SHDN: Shutdown Control Input. The LT4356 can be shut
down to a low current mode by pulling the SHDN pin below
the shutdown threshold of 0.6V. Pull this pin above 1.7V or
disconnect it and allow the internal current source to turn
the part back on. The leakage current to ground at the pin
= 120mV
50
+
: Positive Input of the Auxiliary Amplifi er. This amplifi er
75
4356mp12 G20
100
125
CC
, the EN pin goes high impedance.
–20
–15
–10
–5
0
0
Reverse Current
vs Reverse Voltage
V
CC
= SNS
–20
–40
V
CC
(V)
–60
4356mp12 G21
4356mp12f
–80