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LTC3444_15 Datasheet, PDF (5/20 Pages) Linear Technology – Micropower Synchronous Buck-Boost DC/DC Converter for WCDMA Applications
LTC3444
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 VOUT for a moderate efficiency
improvement. Minimize trace length to keep EMI down.
VOUT (Pin 5): Output of the Synchronous Rectifier. A filter
capacitor is placed from VOUT to GND. A ceramic bypass
capacitor is recommended as close to the VOUT and GND
pins as possible.
VIN (Pin 6): Input Supply Pin. Internal VCC for the IC. A
4.7μF ceramic capacitor is recommended as close to VIN
and GND as possible.
VC (Pin 7): Error Amp Output. Pull VC to ground to select
internal loop compensation. External compensation may
be connected from VC to FB. Internal compensation will be
disabled if VC 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.
3444fb
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