LT3663
5
3663fc
For more information For more information www.linear.com/LT3663
Typical perForMance characTerisTics
BOOST Pin CurrentBoost Diode V
f
T
A
= 25°C, unless otherwise noted.
SWITCH CURRENT (A)
BOOST PIN CURRENT (mA)
35
30
25
20
0
5
15
10
0 0.2 0.4 0.5 0.8 1.0
DIODE CURRENT (mA)
F
1.2
1
0.8
0
0.2
0.6
0.4
0 50 100 150 200 250
SWITCH CURRENT (A)
SWITCH VOLTAGE DROP (mV)
400
350
0
50
100
150
200
250
300
0 0.2 0.4 0.6 0.8 1
125°C
–45°C
25°C
Switch Voltage Drop
pin FuncTions
BOOST: The BOOST pin is used to provide a drive voltage,
higher than the input voltage, to the internal power switch.
The BOOST pin is also internally connected to the cathode
of the BOOST diode.
GND (Exposed Pad Pin 9) : Ground. The exposed pad
must be soldered to the PCB and electrically connected
to ground. Use a large ground plane and thermal vias to
optimize thermal performance.
FB (LT3663): The LT3663 regulates the FB pin to 0.8V.
Connect the feedback resistor divider tap to this pin.
I
LIM
: Output Current Limit Program Pin. Connect a resistor
to ground to program the regulator output current limit.
I
SENSE
: The I
SENSE
pin is the positive input to the internal
output current limit sense resistor. The I
SENSE
pin is also
the anode to the internal BOOST diode.
RUN: The Run pin is used to put the LT3663 into shutdown
mode. Tie to ground to shut down the LT3663. Tie to 2.5V
or more for normal operation. If the shutdown feature is
not used, connect this pin to V
IN
.
SW: The SW pin is the output of the internal power switch.
Connect this pin to the inductor, catch diode and boost
capacitor.
V
IN
: The V
IN
pin supplies current to the LT3663’s internal
regulator and internal power switch. Capacitively bypass
the pin to ground.
V
OUT
: The V
OUT
pin is connected to the negative terminal
of the internal output current limit sense resistor.
V
OUTS
(LT3663-X): Output Voltage Sense Pin. Connect to
the positive terminal of the output capacitor.
