Datasheet LTC3405A (Analog Devices) - 5

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