Datasheet LTC3672B-2 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | Monolithic Fixed-Output 400mA Buck Regulator with Dual 150mA LDOs in 2mm × 2mm DFN |
| Pages / Page | 12 / 1 — FEATURES. DESCRIPTION. Triple Output Supply From a Single 2.9V to 5.5V … |
| File Format / Size | PDF / 161 Kb |
| Document Language | English |
FEATURES. DESCRIPTION. Triple Output Supply From a Single 2.9V to 5.5V Input. Buck DC/DC: Fixed 1.2V Output, Up to 400mA
Model Line for this Datasheet
Text Version of Document
LTC3672B-2 Monolithic Fixed-Output 400mA Buck Regulator with Dual 150mA LDOs in 2mm × 2mm DFN
FEATURES DESCRIPTION
n
Triple Output Supply From a Single 2.9V to 5.5V Input
The LTC®3672B-2 is a triple power supply composed of n
Buck DC/DC: Fixed 1.2V Output, Up to 400mA
a 400mA synchronous buck regulator and two 150mA n
LDO1: Fixed 2.8V Output, Up to 150mA
low-dropout linear regulators (LDOs). Constant-frequency n
LDO2: Fixed 1.8V Output, Up to 150mA
2.25MHz operation is maintained down to very light loads. n
±2.5% Reference Accuracy
The input supply range of 2.9V to 5.5V is especially well- n
Constant-Frequency 2.25MHz Operation
suited for single-cell Lithium-Ion and Lithium-Polymer n Minimum External Component Count applications, and for powering low voltage ASICs from n Current Mode Operation for Excellent Line and Load 3.3V or 5V rails. Transient Response The LTC3672B-2 regulates 1.2V at the buck output, 2.8V n Internal Soft-Start for Each Output at the LDO1 output, and 1.8V at the LDO2 output. Exter- n Single Enable Pin Turns On/Shuts Down All Three nal component count is minimal—all that is needed is a Outputs single inductor, an input capacitor, and output capacitors n Tiny 2mm × 2mm × 0.75mm DFN Package for each of the three outputs. Control loop compensation is internal to the LTC3672B-2.
APPLICATIONS
The LTC3672B-2 is available in a 2mm × 2mm × 0.75mm n 8-Lead DFN package. DMB and DVB-H Cellphones n Handheld Products (PDA, PMP, GPS) , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. n Multivoltage Power for Digital Logic, I/O, FPGAs, CPLDs, ASICs, CPUs, and RF Chipsets
TYPICAL APPLICATION Buck DC/DC Effi ciency vs Buck Load
VIN 2.9V TO 5.5V 100 95 4.7μH VOUT1 2.2μF VIN VIN1 SW 1.2V 90 VIN = 2.9V 4.7μF 400mA 85 GND BUCKOUT 80 VIN = 3.6V LTC3672B-2 VOUT2 ENABLE LDO1 2.8V, UP TO 150mA INPUT ENALL EFFICIENCY (%) 75 (SUBJECT TO DROPOUT 1μF VIN = 5.5V LIMITATIONS) 70 VOUT3 LDO2 65 1.8V 3672B2 TA01 1μF 150mA 60 0 50 100 150 200 250 300 350 400 ILOAD (mA) 3672B2 TA01b 3672b2fa 1
FEATURES DESCRIPTION
n
Triple Output Supply From a Single 2.9V to 5.5V Input
The LTC®3672B-2 is a triple power supply composed of n
Buck DC/DC: Fixed 1.2V Output, Up to 400mA
a 400mA synchronous buck regulator and two 150mA n
LDO1: Fixed 2.8V Output, Up to 150mA
low-dropout linear regulators (LDOs). Constant-frequency n
LDO2: Fixed 1.8V Output, Up to 150mA
2.25MHz operation is maintained down to very light loads. n
±2.5% Reference Accuracy
The input supply range of 2.9V to 5.5V is especially well- n
Constant-Frequency 2.25MHz Operation
suited for single-cell Lithium-Ion and Lithium-Polymer n Minimum External Component Count applications, and for powering low voltage ASICs from n Current Mode Operation for Excellent Line and Load 3.3V or 5V rails. Transient Response The LTC3672B-2 regulates 1.2V at the buck output, 2.8V n Internal Soft-Start for Each Output at the LDO1 output, and 1.8V at the LDO2 output. Exter- n Single Enable Pin Turns On/Shuts Down All Three nal component count is minimal—all that is needed is a Outputs single inductor, an input capacitor, and output capacitors n Tiny 2mm × 2mm × 0.75mm DFN Package for each of the three outputs. Control loop compensation is internal to the LTC3672B-2.
APPLICATIONS
The LTC3672B-2 is available in a 2mm × 2mm × 0.75mm n 8-Lead DFN package. DMB and DVB-H Cellphones n Handheld Products (PDA, PMP, GPS) , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. n Multivoltage Power for Digital Logic, I/O, FPGAs, CPLDs, ASICs, CPUs, and RF Chipsets
TYPICAL APPLICATION Buck DC/DC Effi ciency vs Buck Load
VIN 2.9V TO 5.5V 100 95 4.7μH VOUT1 2.2μF VIN VIN1 SW 1.2V 90 VIN = 2.9V 4.7μF 400mA 85 GND BUCKOUT 80 VIN = 3.6V LTC3672B-2 VOUT2 ENABLE LDO1 2.8V, UP TO 150mA INPUT ENALL EFFICIENCY (%) 75 (SUBJECT TO DROPOUT 1μF VIN = 5.5V LIMITATIONS) 70 VOUT3 LDO2 65 1.8V 3672B2 TA01 1μF 150mA 60 0 50 100 150 200 250 300 350 400 ILOAD (mA) 3672B2 TA01b 3672b2fa 1
