ltc3405a Linear Technology Corporation, ltc3405a Datasheet - Page 5

• Manufacturer Part Number: ltc3405a
• Description: 1.5mhz, 300ma Synchronous Step-down Regulator In Thinsot
• Manufacturer: Linear Technology Corporation

(From Figure 1a Except for the Resistive Divider Resistor Values)
100mV/DIV
200mA/DIV
200mA/DIV
TYPICAL PERFOR A CE CHARACTERISTICS
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.
COUPLED
U
I
V
LOAD
OUT
AC
I
L
Load Step
V
V
I
PULSE SKIPPING MODE
LOAD =
IN
OUT
= 3.6V
U
= 1.8V
20mA TO 250mA
40µs/DIV
U
W
U
3405A G20
100mV/DIV
200mA/DIV
200mA/DIV
COUPLED
I
V
LOAD
OUT
AC
I
L
Load Step
V
V
I
Burst Mode OPERATION
LOAD =
IN
OUT
= 3.6V
= 1.8V
20mA TO 250mA
40µs/DIV
V
to GND, Pin 2, with a 2.2µF or greater ceramic capacitor.
V
from an external resistive divider across the output.
MODE (Pin 6): Mode Select Input. To select pulse skip-
ping mode, tie to V
Mode operation. Do not leave this pin floating.
IN
FB
(Pin 4): Main Supply Pin. Must be closely decoupled
(Pin 5): Feedback Pin. Receives the feedback voltage
3405A G21
100mV/DIV
200mA/DIV
200mA/DIV
COUPLED
IN
I
. Grounding this pin selects Burst
V
LOAD
OUT
AC
I
L
Load Step
V
V
I
Burst Mode OPERATION
LOAD =
IN
OUT
= 3.6V
= 1.8V
0mA TO 250mA
LTC3405A
40µs/DIV
3405afa
3405A G22
5