LTC3525D-3.3 Datasheet, PDF (5/12 Pages) Linear Technology – 400mA Micropower Synchronous Step-Up DC/DC Converter with Pass Through Mode

LTC3525D-3.3
PI FU CTIO S
⎯S⎯H⎯D⎯N (Pin 1): Logic Controlled Shutdown Input. Connect
to a voltage >1V to enable the LTC3525D. Connect to a
voltage <0.4V to disable the LTC3525D and connect V_IN
to V_OUT through the inductor.
GND (Pins 2, 5): Ground.
V_IN (Pin 3): Input Voltage. The LTC3525D is powered from
V_IN until V_OUT exceeds V_IN. Once V_OUT is greater than (V_IN
+ 0.2V typical), it is powered from V_OUT. Place a ceramic
bypass capacitor from V_IN to GND. A minimum value of
1µF is recommended.
V_OUT (Pin 4): Output Voltage Sense and the Output of the
Synchronous Rectifier. Connect the output filter capacitor
from V_OUT to GND, close to the IC. A minimum value of
10µF ceramic is recommended. Use 22µF for reduced
output ripple. The pass-through mode feature connects
V_OUT to V_IN through the inductor when ^⎯S^⎯H^⎯D^⎯N is <0.4V.
SW (Pin 6): Switch Pin. Connect an inductor from this
pin to V_IN. An internal antiringing resistor is connected
across SW and V_IN after the inductor current has dropped
to zero to minimize EMI.
BLOCK DIAGRA
SW
6
V_OUT
V_BEST
V_SEL
VB
V_IN
3
WELL
SWITCH
SHDN 1
SHUTDOWN
SHUTDOWN GATE DRIVERS
AND
ANTI-CROSS
CONDUCTION
+
OFFSET –
V_REF
UVLO
V_REF
UVLO
ADJUST
I_PK
+
STARTUP
SHUTDOWN
THERMAL
TSD
SHUTDOWN
LOGIC
I_PK
COMPARATOR
I_VAL
OFFSET –
ADJUST
I_VALLEY
COMPARATOR
FB
WAKE
INTEGRATOR
V_REF
SLEEP
COMPARATOR
ADJUST
5
2
GND
GND
4 V_OUT
3525 BD
3525d33f
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