5
LTC3444
3444fb
UU
U
PI FU CTIO S
SHDN (Pin 1): Shutdown Function. A logic low input shuts
down the IC. A logic high input enables the IC and starts
the internal soft-start function by limiting the rise time of
the internal PWM command.
SW1 (Pin 2): Switch Pin Where the Internal Switches A
and B are Connected. Connect inductor from SW1 to SW2.
An optional Schottky diode can be connected from ground
to SW1 for a moderate efficiency improvement. Minimize
trace length to minimize EMI.
GND (Pin 3): Ground Pin for the IC.
SW2 (Pin 4): Switch Pin Where the Internal Switches C
and D are Connected. An optional Schottky diode can be
connected from SW2 to V
OUT
for a moderate efficiency
improvement. Minimize trace length to keep EMI down.
V
OUT
(Pin 5): Output of the Synchronous Rectifier. A filter
capacitor is placed from V
OUT
to GND. A ceramic bypass
capacitor is recommended as close to the V
OUT
and GND
pins as possible.
V
IN
(Pin 6): Input Supply Pin. Internal V
CC
for the IC. A
4.7μF ceramic capacitor is recommended as close to V
IN
and GND as possible.
V
C
(Pin 7): Error Amp Output. Pull V
C
to ground to select
internal loop compensation. External compensation may
be connected from V
C
to FB. Internal compensation will be
disabled if V
C
is tied to an external compensation network.
FB (Pin 8): Feedback Pin. Connect resistive divider tap
here. The output voltage can be adjusted from 0.5V to 5V.
The feedback reference voltage is typically 1.22V.
GND (Pin 9, Exposed Pad): Solder to Board GND.
