LTC1735
PI FU CTIO S
V
OSENSE
:
Receives the feedback voltage from an external
resistive divider across the output.
SENSE
–
:
The (–) Input to the Current Comparator.
SENSE
+
:
The (+) Input to the Current Comparator. Built-in
offsets between SENSE
–
and SENSE
+
pins in conjunction
with R
SENSE
set the current trip threshold.
PGOOD (LTC1735F Only):
Open-Drain Logic Output.
PGOOD is pulled to ground when the voltage on the
V
OSENSE
pin is not within
±7.5%
of its set point.
EXTV
CC
:
Input to the Internal Switch Connected to INTV
CC
.
This switch closes and supplies V
CC
power whenever
EXTV
CC
is higher than 4.7V. See EXTV
CC
connection in the
Applications Information section. Do not exceed 7V on
this pin and ensure EXTV
CC
≤
V
IN
.
PGND:
Driver Power Ground. Connects to the source of
bottom N-channel MOSFET, the anode of the Schottky
diode, and the (–) terminal of C
IN
.
BG:
High Current Gate Drive for Bottom
N-Channel MOSFET. Voltage swing at this pin is from
ground to INTV
CC
.
INTV
CC
:
Output of the Internal 5.2V Regulator and EXTV
CC
Switch. The driver and control circuits are powered from
this voltage. Decouple to power ground with a 1µF ceramic
capacitor placed directly adjacent to the IC together with a
minimum of 4.7µF tantalum or other low ESR capacitor.
V
IN
:
Main Supply Pin. Must be closely decoupled to power
ground.
SW:
Switch Node Connection to Inductor and Bootstrap
Capacitor. Voltage swing at this pin is from a Schottky
diode (external) voltage drop below ground to V
IN
.
BOOST:
Supply to Topside Floating Driver. The bootstrap
capacitor is returned to this pin. Voltage swing at this pin
is from a diode drop below INTV
CC
to (V
IN
+ INTV
CC
).
TG:
High Current Gate Drive for Top N-Channel MOSFET.
This is the output of a floating driver with a voltage swing
equal to INTV
CC
superimposed on the switch node voltage
SW.
8
U
U
U
1735fc
LINER [ LINEAR TECHNOLOGY ]
