LTC3525-3.3 Datasheet, PDF (7/12 Pages) Linear Technology – 400mA Micropower Synchronous Step-Up DC/DC Converter with Output Disconnect

LTC3525-3.3/LTC3525-5
PI FU CTIO S
_____
SHDN (Pin 1): Logic Controlled Shutdown Input. Connect
to a voltage >1V to enable the LTC3525. Connect to a
voltage <0.4V to disable the LTC3525.
GND (Pins 2, 5): Ground.
V_IN (Pin 3): Input Voltage. The LTC3525 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 output disconnect feature disconnects
V_OUT from V_IN when SHDN 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
V_REF
V_REF
UVLO
UVLO
I_PK
+
OFFSET –
ADJUST
+
STARTUP
SHUTDOWN
THERMAL
TSD
SHUTDOWN
LOGIC
I_PK
COMPARATOR
I_VAL
OFFSET –
ADJUST
I_VALLEY
COMPARATOR
FB
WAKE
INTEGRATOR
V_REF
SLEEP
COMPARATOR
ADJUST
2
GND
4 V_OUT
3525 BD
3525f
7