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LTC3543EDCB#TRMPBF

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P20
LTC3543
1
3543fa
n
600mA Output Current
n
2.5V to 5.5V Input Voltage Range
n
2.25MHz Constant-Frequency Operation, Spread
Spectrum or Synchronized PLL (1MHz to 3MHz)
n
High Effi ciency: Up to 95%
n
1A Peak Inductor Current
n
Very Low Quiescent Current: Only 45μA During
Burst Mode Operation
n
No Schottky Diode Required
n
Low Dropout Operation: 100% Duty Cycle
n
Overtemperature Protected
n
Stable with Ceramic Capacitors
n
Shutdown Mode Draws <1μA Supply Current
n
±2% Output Voltage Accuracy
n
Current Mode Operation for Excellent Line and Load
Transient Response
n
Soft-Start
n
Available in a Low Profi le (0.75mm) 2mm × 3mm
6-Lead DFN Package
TYPICAL APPLICATION
DESCRIPTION
FEATURES
APPLICATIONS
600mA Synchronous Step
Down Buck Regulator with PLL,
Soft-Start and Spread Spectrum
The LTC
®
3543 is a high effi ciency monolithic synchronous
current mode buck regulator.
The switching frequency is internally set at 2.25MHz,
allowing the use of small surface mount inductors and
capacitors. In PLL mode, the LTC3543 can acquire fre-
quencies between 1MHz and 3MHz. Also, the LTC3543
has spread spectrum capability providing a lower noise
regulated output, as well as low noise at the input.
In Burst Mode
®
operation, the supply current is only 45μA,
dropping to <1μA in shutdown. The 2.5V to 5.5V input
voltage range makes the LTC3543 ideally suited for single
Li-Ion battery-powered applications. The 100% duty cycle
provides a low dropout operation, extending the battery
life in portable systems. Burst Mode
operation increases
effi ciency at light loads, further extending battery life.
The internal synchronous switch increases effi ciency and
eliminates the need for an external Schottky diode.
n
Portable Instruments
n
Cellular Phones
Effi ciency and Power Loss vs Load Current
2.5V TO 5.5V
3543 TA01a
4nF
LTC3543
SWV
IN
V
FB
CAP
RUN
MODE
GND
10pF
10μF
3.3μH
10μF
1.5V
V
OUT
1.5V
300k
200k
EXPOSED
PAD
MODE = V
IN
m PULSE SKIP
MODE = V
FB
m PULSE SKIP WITH SPREAD SPECTRUM
MODE = GND m Burst Mode OPERATION
MODE = EXTERNAL CLOCK m PLL
PWR_EN
MODE
LOAD CURRENT (mA)
30
EFFICIENCY (%)
POWER LOSS (mW)
90
100
20
10
80
50
70
60
40
0.1 10 100 1000
3543 TA01b
0
1000
100
10
10
0.1
1
V
IN
= 3.6V
V
IN
= 4.2V
V
IN
= 2.7V
Burst Mode OPERATION ENABLED
POWER LOSS
AT V
IN
= 3.6V
L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks
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.
LTC3543
2
3543fa
PIN CONFIGURATION ABSOLUTE MAXIMUM RATINGS
ORDER INFORMATION
V
IN
Voltage ................................................... –0.3V to 6V
RUN, V
FB
, MODE, CAP Voltages ...................–0.3V to V
IN
SW Voltage ....................................–0.3V to (V
IN
+ 0.3V)
Operating Temperature Range (Note 2).... –40°C to 85°C
Junction Temperature (Note 3) ............................. 125°C
Storage Temperature Range ................... –65°C to 125°C
(Note 1)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
RUN Run Threshold 0.3 1 1.5 V
V
FB
Regulated Feedback Voltage (Note 4)
l
0.588 0.6 0.612 V
I
VFB
Feedback Pin Current 50 nA
I
PK
Peak Inductor Current V
IN
= 3.6V, V
FB
= 0V 0.7 1 1.3 A
V
LOADREG
Output Voltage Load Regulation 0.5 %/mA
V
LINEREG
Output Voltage Line Regulation (Note 4) 0.5 %/V
V
IN
Input Voltage Range
l
2.5 5.5 V
I
S
Input DC Bias Current
Active Mode
Sleep Mode
Shutdown
(Note 5)
V
OUT
= 90%, I
LOAD
= 0A
V
OUT
= 103%, I
LOAD
= 0A
V
RUN
= 0V, V
IN
= 5.5V
375
45
0.1
500
70
1
μA
μA
μA
f
OSC
Nominal Oscillator Frequency
l
1.80 2.25 MHz
R
PFET
R
DS(ON)
of P-Channel FET I
SW
= 100mA 0.45
Ω
R
NFET
R
DS(ON)
of N-Channel FET I
SW
= 100mA 0.35
Ω
I
SW
SW Leakage V
RUN
= 0V, V
SW
= 0V or 5.5V, V
IN
= 5.5V ±1 μA
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The LTC3543E is guaranteed to meet performance specifi cations
from 0°C to 85°C. Specifi cations over the –40°C to 85°C operating
temperature ranges are assured by design, characterization and
correlation with statistical process controls.
TOP VIEW
V
IN
RUN
VFB
SW
CAP
MODE
DCB PACKAGE
6-LEAD (2mm s 3mm) PLASTIC DFN
4
5
7
6
3
2
1
T
JMAX
= 125°C, θ
JA
= 64°C/W
EXPOSED PAD (PIN 7) IS GND, MUST BE SOLDERED TO PCB
LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3543EDCB#PBF LTC3543EDCB#TRPBF LCCK
6-Lead (2mm × 3mm) Plastic DFN
–40°C to 85°C
Consult LTC Marketing for parts specifi ed with wider operating temperature ranges.
Consult LTC Marketing for information on non-standard lead based fi nish parts.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifi cations, go to:
http://www.linear.com/tapeandreel/
ELECTRICAL CHARACTERISTICS
The l denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
A
= 25°C. V
IN
= 3.6V unless otherwise noted.
LTC3543
3
3543fa
INPUT VOLTAGE (V)
2.5
40
EFFICIENCY (%)
50
60
70
80
100
3.0
3.5 4.0 4.5
3543 G01
5.0 5.5
90
I
OUT
= 200mA
I
OUT
= 10mA
V
OUT
= 1.8V
I
OUT
= 600mA
LOAD CURRENT (mA)
30
EFFICIENCY (%)
90
100
20
10
80
50
70
60
40
0.1 10 100 1000
3543 G02
0
1
V
IN
= 3.6V
V
OUT
= 1.2V
V
IN
= 4.2V
V
IN
= 2.7V
Burst Mode OPERATION
ENABLED
LOAD CURRENT (mA)
30
EFFICIENCY (%)
90
100
20
10
80
50
70
60
40
0.1 10 100 1000
3543 G03
0
1
V
IN
= 3.6V
V
OUT
= 1.5V
V
IN
= 4.2V
V
IN
= 2.7V
Burst Mode OPERATION
ENABLED
LOAD CURRENT (mA)
100
POWER LOSS (mW)
200
300
400
500
0.1 10 100 1000
3543 G04
0
1
V
OUT
= 1.2V
V
OUT
= 1.5V
V
OUT
= 1.8V
V
OUT
= 2.5V
LOAD CURRENT (mA)
30
EFFICIENCY (%)
90
100
20
10
80
50
70
60
40
0.1 10 100 1000
3543 G05
0
1
V
IN
= 3.6V
V
OUT
= 1.8V
V
IN
= 4.2V
V
IN
= 2.7V
Burst Mode OPERATION
ENABLED
LOAD CURRENT (mA)
30
EFFICIENCY (%)
90
100
20
10
80
50
70
60
40
0.1 10 100 1000
3543 G06
0
1
V
IN
= 3.6V
V
OUT
= 2.5V
V
IN
= 4.2V
V
IN
= 2.7V
Burst Mode OPERATION
ENABLED
Effi ciency vs Input Voltage (V
IN
) Effi ciency vs Load Current Effi ciency vs Load Current
Power Loss vs Load Current Effi ciency vs Load Current
Effi ciency vs Load Current
ELECTRICAL CHARACTERISTICS
Note 3: T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formula: T
J
= T
A
+ (P
D
)(64°C/W)
Note 4: The LTC3543 is tested in a proprietary test mode that connects
V
FB
to the output of the error amplifi er. This test mode is equivalent to
continuous mode operation.
Note 5: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency.
TYPICAL PERFORMANCE CHARACTERISTICS
T
A
= 25°C unless otherwise noted. (From Figure 1a)
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P20

LTC3543EDCB#TRMPBF

Mfr. #:
Buy LTC3543EDCB#TRMPBF
Manufacturer:
Analog Devices / Linear Technology
Description:
Switching Voltage Regulators Buck Regulator w/ PLL, Soft Start & Spread Spectrum in DFN
Lifecycle:
New from this manufacturer.
Delivery:
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