LT3653
5
3653f
TYPICAL PERFORMANCE CHARACTERISTICS
V
C
Current V
C
Operating Range
PIN FUNCTIONS
V
IN
(Pin 1): The V
IN
pin supplies current to the LT3653’s
internal regulator and the internal power switch. Locally
bypass this pin with a capacitor.
HVOK (Pin 2): The HVOK pin is a status pin which indi-
cates that the internal bias rail is present and that an input
undervoltage lockout fault, an overvoltage lockout fault or
an over temperature fault are not present.
V
C
(Pin 3): The V
C
pin is the output of the internal error
amplifi er and is internally compensated. The voltage on this
pin controls the peak switch current. Connect this pin to
the battery charger V
C
pin for battery tracking function.
I
LIM
(Pin 4): Connect a resistor to GND to program the
output current limit of the regulator. See the I
LIM
Resistor
section in Application Information.
V
OUT
(Pin 5): The V
OUT
pin is connected to the negative
terminal of the internal current sense resistor of the output
current limit circuit. Maximum V
OUT
voltage is regulated
to 4.8V.
I
SENSE
(Pin 6): The I
SENSE
pin is the positive input to the
internal current sense resistor of the output current limit
circuit. The I
SENSE
pin is also the anode of the internal
BOOST diode.
BOOST (Pin 7): The BOOST pin provides a drive voltage,
higher than the input voltage, to the internal power switch.
The BOOST pin is internally connected to the cathode of
the BOOST diode.
SW (Pin 8): The SW pin is the output of the internal power
switch. Connect this pin to the inductor, catch diode and
boost capacitor.
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 vias to optimize thermal
performance.
V
OUT
(V)
VC PIN CURRENT (μA)
15
10
3653 G09
–25
–20
–15
–10
–5
0
5
4 4.4 4.8 5.2 5.6 6
TEMPERATURE (ºC)
VC VOLTAGE (V)
2.0
1.8
0.0
3653 G10
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
-50 -25 0 25 50 75 100 125
CURRENT LIMIT CLAMP
SWITCHING THRESHOLD
T
A
= 25°C unless otherwise noted
