LTC3545/LTC3545-1
7
35451fb
PIN FUNCTIONS
SW1 (Pin 1): Switch Node Connection to Inductor for
Regulator 1. This pin connects to the internal power
MOSFET switches.
PGOOD1 (Pin 2): This open-drain output voltage is pulled
to a logic low when V
FB1
is below 0.54V (V
OUT1
is below
90% of regulated level).
RUN2 (Pin 3): Regulator 2 Enable Pin. Apply a voltage
greater than V
RUN(HIGH)
to enable this regulator.
PGOOD2 (Pin 4): This open-drain output voltage is pulled
to a logic low when V
FB2
is below 0.54V (V
OUT2
is below
90% of regulated level).
SW2 (Pin 5): Switch Node Connection to Inductor for
Regulator 2. This pin connects to the internal power
MOSFET switches.
PGND (Pin 6): Regulators 2 and 3 Power Path Return.
PV
IN
(Pin 7): Power Path Supply Pin for Regulators 2 and
3. This pin must be closely decoupled to PGND, with a
4.7µF or greater ceramic capacitor.
SW3 (Pin 8): Switch Node Connection to Inductor for
Regulator 3. This pin connects to the internal power
MOSFET switches.
SYNC/MODE (Pin 9, LTC3545 Only): Mode Select and
External Clock Input. When pulled low, part operates in
Burst Mode operation. When pulled high, part operates
in pulse skipping mode. When driven by a 1MHz to 3MHz
external clock, the part operates in pulse skipping mode
with a switching frequency equal to the external clock.
PGOOD3 (Pin 9, LTC3545-1 Only): This open-drain output
voltage is pulled to a logic low when V
FB3
is below 0.54V
(V
OUT3
is below 90% of regulated level). The LTC3545-1
operates in Burst Mode operation only.
RUN3 (Pin 10): Regulator 3 Enable Pin. Apply a voltage
greater than V
RUN(HIGH)
to enable this regulator.
V
FB3
(Pin 11): Regulator 3 Feedback Pin. This pin receives
the feedback voltage from an external resistive divider
across the output.
V
FB2
(Pin 12): Regulator 2 Feedback Pin. This pin receives
the feedback voltage from an external resistive divider
across the output.
V
FB1
(Pin 13): Regulator 1 Feedback Pin. This pin receives
the feedback voltage from an external resistive divider
across the output.
RUN1 (Pin 14): Regulator 1 Enable Pin. Apply a voltage
greater than V
RUN(HIGH)
to enable this regulator.
V
IN
(Pin 15): Supply Pin for Internal Reference and Control
Circuitry. Power path supply for regulator 1.
GNDA (Pin 16): Ground Pin for Internal Reference and
Control Circuitry. Power path return for regulator 1.
Exposed Pad (Pin 17): GND. Must be soldered to the
PCB.
