Step-Down Regulator. LTC3544 Datasheet

LTC3544 Regulator. Datasheet pdf. Equivalent

Part LTC3544
Description Quad Synchronous Step-Down Regulator
Feature LTC3544 Quad Synchronous Step-Down Regulator: 2.25MHz, 300mA, 200mA, 200mA, 100mA FEATURES ■ High E.
Manufacture Linear Technology
Datasheet
Download LTC3544 Datasheet




LTC3544
LTC3544
Quad Synchronous
Step-Down Regulator: 2.25MHz,
300mA, 200mA, 200mA, 100mA
FEATURES
High Efficiency: Up to 95%
Four Independent Regulators Provide Up to 300mA,
200mA, 200mA and 100mA Output Current
2.25V to 5.5V Input Voltage Range
2.25MHz Constant-Frequency Operation
No Schottky Diodes Required
Extremely Low Channel-to-Channel Transient
Crosstalk
Low Ripple (20mVP-P) Burst Mode Operation:
IQ = 70μA (All Channels On)
0.8V Reference Allows Low Output Voltages
Shutdown Mode Draws <1μA Supply Current
Current Mode Operation for Excellent Line and Load
Transient Response
Overtemperature Protected
Low Profile (3mm × 3mm) 16-Lead QFN Package
APPLICATIONS
Cellular Telephones
Personal Information Appliances
Wireless and DSL Modems
Digital Still Cameras
Media Players
Portable Instruments
DESCRIPTION
The LTC®3544 is a quad, high efficiency, monolithic
synchronous buck regulator using a constant-frequency,
current mode architecture. The four regulators operate
independently with separate run pins. The 2.25V to 5.5V
input voltage range makes the LTC3544 well suited for
single Li-Ion/polymer battery-powered applications.
100% duty cycle provides low dropout operation, ex-
tending battery runtime in portable systems. Low ripple
Burst Mode® operation increases efficiency at light loads,
further extending battery runtime with typically only 20mV
of ripple.
Switching frequency is internally set to 2.25MHz, allowing
the use of small surface mount inductors and capacitors.
The internal synchronous switches increase efficiency
and eliminate the need for external Schottky diodes. Low
output voltages are easily supported with the 0.8V feedback
reference voltage.
The LTC3544 is available in a low profile (0.75mm) (3mm
× 3mm) QFN package.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
Burst Mode is a registered trademark of Linear Technology Corporation. All other
trademarks are the property of their respective owners. Protected by U.S. Patents,
including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131, 5994885.
TYPICAL APPLICATION
High Efficiency Quad Step-Down Converter
VIN
2.25V TO 5.5V
VOUT2
1.5V
200mA
4.7μF
CER
4.7μF
CER
4.7μH
93.1k
107k
VOUT4
1.8V
300mA
4.7μF
CER
3.3μH
133k
107k
VCC
RUN200B
SW200B
VFB200B
PVIN
RUN200A
SW200A
VFB200A
LTC3544
RUN300
SW300
VFB300
GNDA
RUN100
SW100
VFB100
PGND
3.3μH
100k
VOUT3
0.8V
200mA
4.7μF
CER
10μH
59k
118k
VOUT1
1.2V
100mA
4.7μF
CER
3544B TA01a
Efficiency vs Load Current, 300mA
Channel, All Other Channels Off
100 1
90
80 EFFICIENCY
70
0.1
60 LOSS
50 VOUT = 2.5V
40 TA = 25°C
0.01
30
20
10
0
0.0001
0.001
0.001
0.01
VIN = 2.7V
VIN = 3.6V
VIN = 4.2V 0.0001
0.1 1
LOAD CURRENT (A)
3544 TA01b
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LTC3544
LTC3544
ABSOLUTE MAXIMUM RATINGS
(Note 1)
Input Supply Voltage .....................................–0.3V to 6V
RUNx ............................................. –0.3V to (VIN + 0.3V)
VFBx................................................ –0.3V to (VIN + 0.3V)
SWx ............................................... –0.3V to (VIN + 0.3V)
300mA P-Channel Source Current (DC) (Note 8) ..450mA
300mA N-Channel Sink Current (DC) (Note 8) ......450mA
200mA P-Channel Source Current (DC) (Note 8) ..300mA
200mA N-Channel Sink Current (DC) (Note 8) ......300mA
100mA P-Channel Source Current (DC) (Note 8) ..200mA
100mA N-Channel Sink Current (DC) (Note 8) ......200mA
Peak 300mA SW Sink and Source Current
(Note 8)................................................................600mA
Peak 200mA SW Sink and Source Current
(Note 8)................................................................400mA
Peak 100mA SW Sink and Source Current
(Note 8)................................................................200mA
Operating Temperature Range...................–40°C to 85°C
Junction Temperature (Notes 3, 4) ........................ 125°C
Storage Temperature Range ....................–65°C to 125°C
PIN CONFIGURATION
TOP VIEW
16 15 14 13
VFB200B 1
12 RUN100
VFB200A 2 17 11 VFB100
RUN200A 3
10 VFB300
SW200B 4
9 RUN300
5678
UD PACKAGE
16-LEAD (3mm × 3mm) PLASTIC QFN
TJMAX = 125°C, θJA = 68°C/W
EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
LTC3544EUD#PBF
LTC3544EUD#TRPBF LCXM
16-Lead (3mm × 3mm) Plastic QFN
LEAD BASED FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
LTC3544EUD
LTC3544EUD#TR
LCXM
16-Lead (3mm × 3mm) Plastic QFN
Consult LTC Marketing for parts specified with wider operating temperature ranges.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
TEMPERATURE RANGE
–40°C to 85°C
TEMPERATURE RANGE
–40°C to 85°C
ELECTRICAL CHARACTERISTICS The denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VIN = 3.6V unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
MIN TYP MAX UNITS
General Characteristics
VIN
VFBREGx
Input Voltage Range
Regulated Feedback Voltage (Note 5)
2.25
5.5
0.792 0.8 0.808
0.784 0.8 0.816
V
V
V
ΔVFBREGx
VLOADREG
Reference Voltage Line Regulation (Note 5)
Output Voltage Load Regulation (Note 6)
VIN = 2.25V to 5.5V
0.05 0.25
0.5
%/V
%
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