LTC3548A Datasheet, PDF (6/20 Pages) Linear Technology – Dual Synchronous 400mA/800mA, 2.25MHz Step-Down DC/DC Regulator

LTC3548A
PIN FUNCTIONS
V_FB1 (Pin 1): Output Feedback. Receives the feedback volt-
age from the external resistive divider across the output.
Nominal voltage for this pin is 0.6V.
RUN/SS1 (Pin 2): Regulator 1 Enable and Soft-Start Input.
Forcing this pin to V_IN enables regulator 1, while forcing it
to GND causes regulator 1 to shut down. Connect external
RC network with desired time-constant to enable soft-start
feature. This pin must be driven; do not float.
V_IN (Pin 3): Main Power Supply. Must be closely decoupled
to GND.
SW1 (Pin 4): Regulator 1 Switch Node Connection to the
Inductor. This pin swings from V_IN to GND.
NC (Pin 5): No Connect. This pin is not connected inter-
nally. Connect to ground on PCB for shielding purposes.
MODE/SYNC (Pin 6): Combination Mode Selection and
Oscillator Synchronization. This pin controls the opera-
tion of the device. When tied to V_IN or GND, Burst Mode
operation or pulse-skipping mode is selected, respectively.
Do not float this pin. The oscillation frequency can be
synchronized to an external oscillator applied to this pin
and pulse-skipping mode is automatically selected.
SW2 (Pin 7): Regulator 2 Switch Node Connection to the
Inductor. This pin swings from V_IN to GND.
POR (Pin 8): Power-On Reset. This common-drain logic
output is pulled to GND when the output voltage is not
within ±8.5% of regulation and goes high after 2¹⁶ clock
cycles when both channels are within regulation.
RUN/SS2 (Pin 9): Regulator 2 Enable and Soft-Start Input.
Forcing this pin to V_IN enables regulator 2, while forcing it
to GND causes regulator 2 to shut down. Connect external
RC network with desired time-constant to enable soft-start
feature. This pin must be driven; do not float.
V_FB2 (Pin 10): Output Feedback. Receives the feedback
voltage from the external resistive divider across the output.
Nominal voltage for this pin is 0.6V.
Exposed Pad (GND) (Pin 11): Power Ground. Connect to
the (–) terminal of C_OUT, and (–) terminal of C_IN. Must be
soldered to electrical ground on PCB.
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