Linear Technology DEMO CIRCUIT 1324A Quick Start Manual

DESCRIPTION
Demonstration Circuit 1324A is a monolithic 400mA
Buck regulator, with fixed output, and two 150mA,
Low Drop Out linear regulators. These are housed in
an 8 lead, 2mm X 2mm DFN package.
PERFORMANCE SUMMARY
SYMBOL PARAMETER
VIN Input voltage
VOUT1 Output of regulator (buck) 1
VOUT2 Output of LDO1
VOUT3 Output of LDO2
OPERATING PRINCIPLES
The LTC3672BEDC-2 is a monolithic fixed output,
400mA, synchronous buck regulator and two 150mA
LDOS.
VOUT1 is driven by a high efficiency synchronous buck
regulator with a fixed output of 1.2V. The buck regulator
on the LTC3672BEDC-2 operates at approximately
2.25MHz, allowing the use of small inductors and
capacitors.
The two fixed output LDOs, have a maximum dropout
voltage of 250mV, over process and temperature. This
allows all three outputs to remain in regulation with VIN
as low as 2.98V.
All of the regulators on the LTC3672BEDC-2 are enabled
via the ENALL pin, controlled by JP1.
Arrow.com.
Downloaded from
Fixed-Output 400mA Buck Regulator with Dual
150mA LDOs in 2mm X 2mm DFN
Specifications are at T
CONDITIONS
I ≤ 400mA
OUT1
I ≤ 150mA. Subject to dropout limitations.
OUT2
IOUT3 ≤ 150mA
DEMO CIRCUIT 1324A
QUICK START GUIDE
LTC3672BEDC-2: Monolithic
Design files for this circuit board are available. Call
the LTC factory.
L
, LTC, LTM, LT, Burst Mode, OPTI-LOOP, Over-The-Top and PolyPhase are registered
trademarks of Linear Technology Corporation. Adaptive Power, C-Load, DirectSense, Easy
Drive, FilterCAD, Hot Swap, LinearView, μModule, Micropower SwitcherCAD, Multimode
Dimming, No Latency ΔΣ, No Latency Delta-Sigma, No R
PowerPath, PowerSOT, SmartStart, SoftSpan, Stage Shedding, SwitcherCAD, ThinSOT,
UltraFast and VLDO are trademarks of Linear Technology Corporation. Other product names
may be trademarks of the companies that manufacture the products.
= 25°C
A
LTC3672BEDC-1
VOUT = 1.2V
100
90
80
70
60
50
40
30
20
0 100
LOAD CURRENT [mA]
Efficiency of the Buck regulator at VIN = 3.6V
PDC
, Operational Filter, PanelProtect,
SENSE
MIN TYP MAX UNITS
2.9 5.5
1.17 1.23
2.73 2.87
1.755 1.845
200 300 400
V
V
V
V
1