LTC3525L-3_15 Datasheet, PDF (5/12 Pages) Linear Technology – 400mA Micropower Synchronous Step-Up DC/DC Converter with Output Disconnect

LTC3525L-3
PIN FUNCTIONS
SHDN (Pin 1): Logic-Controlled Shutdown Input. Connect
to a voltage >0.88V to enable the LTC3525L-3. Connect to
a voltage <0.3V to disable the LTC3525L-3.
GND (Pins 2, 5): Ground.
V_IN (Pin 3): Input Voltage. The LTC3525L-3 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 <0.3V.
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 DIAGRAM
V_OUT
V_BEST
V_SEL
VB
10µH
SW
6
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
+
START-UP
LOGIC
I_PK
COMPARATOR
I_VAL
OFFSET –
ADJUST
SHUTDOWN
THERMAL
TSD
SHUTDOWN
I_VALLEY
COMPARATOR
FB
WAKE
V_REF
INTEGRATOR
SLEEP
COMPARATOR
ADJUST
5
GND
2
GND
V_IN
1µF
V_OUT
4
V_OUT
10µF
3525L BD
3525lfa
5