Datasheet

LTC3103
7
3103f
PIN FUNCTIONS
V
IN
(Pin 1): Main Supply Pin. Decouple with a 10µF or
larger ceramic capacitor. The capacitor should be as close
to the part as possible.
SW (Pin 2): Switch Pin Connects to the Inductor. This pin
connects to the drains of the internal main and synchronous
power MOSFET switches.
BST (Pin 3): Bootstrapped Floating Supply for the High
Side Gate Drive. Connect to SW through a 22nF (minimum)
capacitor. The capacitor must be connected between BST
and SW and be located as close as possible to the part
as possible.
GND (Pin 4): Power Ground.
PGOOD (Pin 5): Open-drain output that is pulled to ground
when the feedback voltage falls 10% (typical) below the
regulation point, during a thermal shutdown event or if
the converter is disabled. The PGOOD output is valid 1ms
after the buck converter is enabled.
V
CC
(Pin 6): Internally Regulated Supply Rail. Internal
power rail regulated off of V
IN
to power control circuitry.
Decouple with a 1µF or larger ceramic capacitor placed
as close to the part as possible.
RUN (Pin 7): Run Pin Comparator Input. A voltage greater
than 0.84V will enable the IC. Tie this pin to V
IN
to enable
the IC or connect to an external resistor divider from V
IN
to provide an accurate undervoltage lockout threshold.
60mV of hysteresis is provided internally.
FB (Pin 8): Feedback Input to Error Amplifier. The resis-
tor divider connected to this pin sets the buck converter
output voltage.
NC (Pin 9): No Connect Pin Must be Tied to GND.
MODE (Pin 10): Logic-Controlled Input to Select Mode
of Operation. Forcing this pin high commands high ef-
ficiency automatic Burst Mode operation where the buck
will automatically transition from PWM operation at heavy
load to Burst Mode operation at light loads. Forcing this
pin low commands low noise, fixed frequency, forced
continuous operation.
GND (Exposed Pad Pin 11): Backpad Ground Common.
This pad must be soldered to the PC board and connected
to the ground plane for optimal thermal performance.