LTC3670
1
3670f
TYPICAL APPLICATION
FEATURES
APPLICATIONS
DESCRIPTION
Monolithic 400mA Buck
Regulator with Dual 150mA
LDOs in 3mm ?2mm DFN
The LTC
?/DIV>
3670 is a triple power supply composed of a
400mA synchronous buck regulator and two 150mA low
dropout linear regulators (LDOs). The input supply range
of 2.5V to 5.5V is especially well-suited for single-cell
Lithium-Ion and Lithium-Ion/Polymer applications, and
for powering low voltage ASICs and SoCs from 3V, 3.3V
or 5V rails. Regulated output voltages are programmed
via external resistors. Each output has its own enable pin
for maximum exibility.
The 400mA buck regulator features constant-frequency
2.25MHz operation, allowing small surface mount induc-
tors and capacitors to be used. Burst Mode operation
maintains high ef ciency in light-load and no-load con-
ditions. Internal control-loop compensation simpli es
application design.
The LTC3670 is available in a 0.75mm pro le, 3mm ?
2mm 12-lead DFN package.
Triple Power Supply with Independent Enables
n
Triple Output Supply from a Single 2.5V to 5.5V Input
n
400mA Buck DC/DC Plus Dual 150mA LDOs in One IC
n
Outputs Regulate Down to 0.8V
n
?/SPAN>2.5% Reference Accuracy
n
Constant-Frequency 2.25MHz Operation
n
Burst Mode
?/DIV>
Operation for High Ef ciency at Light
Loads; I
Q
= 70糀, All Outputs Enabled
n
Independent Enable Pin for Each Output
n
Current Mode Operation for Excellent Line and Load
Transient Response
n
Internal Soft-Start for Each Output
n
Tiny 12-Lead 3mm ?2mm ?0.75mm DFN Package
n
Handheld Products
n
Portable Instruments
n
Single-Cell Li-Ion/Li-Polymer Powered Devices
n
DMB/DVB-H Multimedia Cell Phones
n
Multivoltage Power for Digital Logic, I/O, FPGAs,
CPLDs, ASICs, SoCs, CPUs and RF Chipsets
L, LT, LTC, LTM and Burst Mode are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners. Patents pending.
V
IN
LTC3670
V
IN
3.3V TO 5.5V
SW
4.7糎
232k
2.2糉
464k
V
OUT1
1.2V
400mA
10pF
4.7糉
BUCKFB
GND
ENBUCK
ENLDO1
ENLDO2
PGOOD
LDO1
LDO1_FB
DIGITAL
CONTROL
LDO2_FB
806k
324k
V
OUT2
2.8V
150mA
1糉
LDO2
1.02M
324k
V
OUT3
3.3V
150mA
1糉
3670 TA01a
Demoboard
3670 TA01b
9.4mm
ACTIVE AREA
9.3mm