LTC3670_15 Datasheet, PDF (1/12 Pages) Linear Technology – Monolithic 400mA Buck Regulator with Dual 150mA

LTC3670
Monolithic 400mA Buck
Regulator with Dual 150mA
LDOs in 3mm × 2mm DFN
FEATURES
DESCRIPTION
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 _{±2.5% Reference Accuracy}
n _{Constant-Frequency 2.25MHz Operation}
n _{Burst Mode}^® _{Operation for High Efficiency at Light}
Loads; I_Q = 70μA, 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}
APPLICATIONS
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
The LTC^®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 flexibility.
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 efficiency in light-load and no-load con-
ditions. Internal control-loop compensation simplifies
application design.
The LTC3670 is available in a 0.75mm profile, 3mm ×
2mm 12-lead DFN package.
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.
TYPICAL APPLICATION
Triple Power Supply with Independent Enables
V_IN
3.3V TO 5.5V
2.2μF
DIGITAL
CONTROL
V_IN
GND
4.7μH
SW
232k
10pF
BUCKFB
464k
LTC3670
ENBUCK
LDO1
ENLDO1
ENLDO2
806k
PGOOD ^LDO1_FB
324k
LDO2
LDO2_FB
1.02M
324k
3670 TA01a
V_OUT1
1.2V
4.7μF ^400mA
V_OUT2
2.8V
1μF ^150mA
V_OUT3
3.3V
1μF ^150mA
Demoboard
9.3mm
9.4mm
ACTIVE AREA
3670 TA01b
3670f
1