LTC3408EDD Linear Technology, LTC3408EDD Datasheet - Page 5

• Manufacturer Part Number: LTC3408EDD
• Description: IC REG BUCK W/BYPASS TXRX 8-DFN
• Manufacturer: Linear Technology

Specifications of LTC3408EDD

• Applications: Converter, WCDMA Power Amplifier Applications
• Voltage - Input: 2.5 ~ 5 V
• Number Of Outputs: 1
• Voltage - Output: 0.3 ~ 3.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-DFN
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

TYPICAL PERFOR A CE CHARACTERISTICS
PI FU CTIO S
V
resistive divider divides the output voltage down by 3 for
comparison to the external reference voltage. The drain of
the P-channel bypass MOSFET is connected to this pin.
V
coupled to GND, Pin 3, with a 10µF or greater ceramic
capacitor.
GND (Pin 3): Ground Pin.
SW (Pin 4): Switch Node Connection to Inductor. This pin
connects to the drains of the internal main and synchro-
nous power MOSFET switches.
OUT
IN
U
(Pins 2, 7): Main Supply Pin. Must be closely de-
(Pins 1, 8): Output Voltage Feedback Pin. An internal
U
100mA/DIV
10mV/DIV
0.5V/DIV
1V/DIV
V
V
V
OUT
OUT
REF
I
L
V
V
R
Output Ripple Waveform
V
V
I
REF Transient
LOAD
U
IN
REF
LOAD
IN
REF
= 4.2V
= 3.6V
= 0V TO 1.4V
= 0.6V
= 0A
= 5Ω
W
200ns/DIV
40µs/DIV
U
3408 G18
3408 G16
RUN (Pin 5): 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.
REF (Pin 6): External Reference Input. Controls the output
voltage to 3× the applied voltage at REF. Also turns on the
bypass MOSFET when V
Exposed Pad (Pin 9): Connect to GND, Pin 3.
100mV/DIV
500mA/DIV
500mA/DIV
I
V
LOAD
OUT
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
I
(From Figure 1)
0
L
V
V
I
0
Load Step Response
V
LOAD
IN
REF
V
OUT
IN
= 3.6V
= 0.6V
= 4.2V
= 0mA TO 600mA
vs V
REF
0.5
20µs/DIV
V
REF
I
REF
I
L
L
= 600mA
= 100mA
(V)
> 1.2V.
1.0
3408 G17
3408 G19
1.5
LTC3408
5
3408f