LTC3405A_15 Datasheet, PDF (5/16 Pages) Linear Technology – 1.5MHz, 300mA Synchronous Step-Down Regulator in ThinSOT

TYPICAL PERFOR A CE CHARACTERISTICS
(From Figure 1a Except for the Resistive Divider Resistor Values)
LTC3405A
Load Step
V_OUT
100mV/DIV
AC
COUPLED
I_L
200mA/DIV
Load Step
V_OUT
100mV/DIV
AC
COUPLED
I_L
200mA/DIV
Load Step
V_OUT
100mV/DIV
AC
COUPLED
I_L
200mA/DIV
I_LOAD
200mA/DIV
V_IN = 3.6V
40µs/DIV
V_OUT = 1.8V
I_LOAD = 20mA TO 250mA
PULSE SKIPPING MODE
I_LOAD
200mA/DIV
3405A G20
V_IN = 3.6V
40µs/DIV
V_OUT = 1.8V
I_LOAD = 20mA TO 250mA
Burst Mode OPERATION
I_LOAD
200mA/DIV
3405A G21
V_IN = 3.6V
40µs/DIV
V_OUT = 1.8V
I_LOAD = 0mA TO 250mA
Burst Mode OPERATION
3405A G22
PI FU CTIO S
RUN (Pin 1): Run Control Input. Forcing this pin above
1.5V enables the part. Forcing this pin below 0.3V shuts
down the device. In shutdown, all functions are disabled
drawing <1µA supply current. Do not leave RUN floating.
GND (Pin 2): Ground Pin.
SW (Pin 3): Switch Node Connection to Inductor. This pin
connects to the drains of the internal main and synchro-
nous power MOSFET switches.
V_IN (Pin 4): Main Supply Pin. Must be closely decoupled
to GND, Pin 2, with a 2.2µF or greater ceramic capacitor.
V_FB (Pin 5): Feedback Pin. Receives the feedback voltage
from an external resistive divider across the output.
MODE (Pin 6): Mode Select Input. To select pulse skip-
ping mode, tie to V_IN. Grounding this pin selects Burst
Mode operation. Do not leave this pin floating.
3405afa
5