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LTC3547BEDDB-1#TRMPBF

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P16
LTC3547B
1
3547bfb
OUTPUT CURRENT (mA)
30
EFFICIENCY (%)
POWER LOSS (W)
90
100
20
10
80
50
70
60
40
1 100 1000
3547b TA01b
0
1
0.1
0.01
0.001
10
V
IN
= 2.7V
V
IN
= 3.6V
V
IN
= 4.2V
Dual Monolithic
300mA Synchronous
Step-Down Regulator
The LTC
®
3547B is a dual, 2.25MHz, constant-frequency,
synchronous step-down DC/DC converter in a tiny 3mm ×
2mm DFN package. 100% duty cycle provides low drop-
out operation, extending battery life in portable systems.
Low output voltages are supported with the 0.6V feed-
back reference voltage. Each regulator can supply 300mA
continuous output current.
The input voltage range is 2.5V to 5.5V, making it ideal
for Li-Ion polymer and USB powered applications. Supply
current is only 1μA in shutdown.
An internally set 2.25MHz switching frequency allows the
use of tiny surface mount inductors and capacitors. Inter-
nal soft-start reduces inrush current during start-up. All
outputs are internally compensated to work with ceramic
capacitors. The LTC3547B is available in a low profi le
(0.75mm) 3mm × 2mm DFN package. The LTC3547B
is also available in a fi xed output voltage confi guration
selected via internal resistor dividers (see Table 2).
■
Cellular Telephones
■
Digital Still Cameras
■
Wireless and DSL Modems
■
Portable Media Players
■
PDAs/Palmtop PCs
■
High Effi ciency (Up to 96%) Dual Step-Down
Outputs
■
300mA Output Current per Channel at V
IN
= 3V
■
2.25MHz Constant-Frequency Operation
■
2.5V to 5.5V Input Voltage Range
■
Low Dropout Operation: 100% Duty Cycle
■
No Schottky Diodes Required
■
Internally Compensated for All Ceramic Capacitors
■
Independent Internal Soft-Start for Each Channel
■
Available in Fixed Output Versions
■
Current Mode Operation for Excellent Line and Load
Transient Response
■
0.6V Reference Allows Low Output Voltages
■
Short-Circuit Protected
■
Ultralow Shutdown Current: I
Q
< 1μA
■
Low Profi le (0.75mm) 8-Lead 3mm × 2mm
DFN Package
Dual Monolithic Buck Regulator in 8-Lead 3mm × 2mm DFN
APPLICATIO S
U
FEATURES
DESCRIPTIO
U
TYPICAL APPLICATIO
U
, 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 6580258, 5481178, 6304066, 6127815, 6498466, 6611131.
V
IN
RUN2 RUN1
LTC3547B
V
FB2
SW2
SW1
V
FB1
10pF 10pF
GND
V
IN
2.5V TO 5.5V
V
OUT2
1.8V AT
300mA
V
OUT1
2.5V AT
300mA
3547b TA01
237k 150k
475k
4.7
μH 4.7μH
475k
4.7μF
4.7
μF
4.7
μF
Effi ciency vs Output Current
for V
OUT
= 2.5V
LTC3547B
2
3547bfb
V
IN
LTC3547BE .............................................. –0.3V to 6V
LTC3547BI ............................................... –0.3V to 7V
V
FB1
, V
FB2
......................................... –0.3V to V
IN
+0.3V
RUN1, RUN2 ..................................... –0.3V to V
IN
+0.3V
SW1, SW2 (DC) ................................ –0.3V to V
IN
+0.3V
P-Channel Switch Source Current (DC)................500mA
N-Channel Switch Sink Current (DC) ...................500mA
Peak SW Sink and Source Current (Note 5) .........700mA
Ambient Operating Temperature Range (Note 2)
LTC3547BE .......................................... –40°C to 85°C
LTC3547BI ......................................... –40°C to 125°C
Maximum Junction Temperature........................... 125°C
Storage Temperature Range ................... –65°C to 125°C
(Note 1)
The ● 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.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IN
V
IN
Operating Voltage LTC3547BE, LTC3547BE-1,
LTC3547BI
●
●
2.5
2.5
5.5
6.5
V
V
V
UV
V
IN
Undervoltage Lockout V
IN
Low to High
●
2.2 2.5 V
I
FB
Feedback Pin Input Current LTC3547BE, V
FB
= V
FBREG
LTC3547BE-1, V
FB
= V
FBREG
●
●
3
±30
6
nA
μA
V
FBREG1
Regulated Feedback Voltage (V
FB1
) LTC3547BE, 0°C ≤ T
A
≤ 85°C
LTC3547BE, –40°C ≤ T
A
≤ 85°C
LTC3547BI, –40°C ≤ T
A
≤ 125°C
LTC3547BE-1, 0°C ≤ T
A
≤ 85°C
LTC3547BE-1, –40°C ≤ T
A
≤ 85°C
●
●
●
0.590
0.588
0.588
1.770
1.764
0.600
0.600
0.600
1.800
1.800
0.610
0.612
0.612
1.830
1.836
V
V
V
V
V
V
FBREG2
Regulated Feedback Voltage (V
FB2
) LTC3547BE, 0°C ≤ T
A
≤ 85°C
LTC3547BE, –40°C ≤ T
A
≤ 85°C
LTC3547BI, –40°C ≤ T
A
≤ 125°C
LTC3547BE-1, 0°C ≤ T
A
≤ 85°C
LTC3547BE-1, –40°C ≤ T
A
≤ 85°C
●
●
●
0.590
0.588
0.588
1.180
1.176
0.600
0.600
0.600
1.200
1.200
0.610
0.612
0.612
1.220
1.224
V
V
V
V
V
ELECTRICAL CHARACTERISTICS
ABSOLUTE AXI U RATI GS
W
WW
U
TOP VIEW
9
DDB PACKAGE
8-LEAD (3mm × 2mm) PLASTIC DFN
5
6
7
8
4
3
2
1V
FB1
RUN1
V
IN
SW1
V
FB2
RUN2
SW2
GND
T
JMAX
= 125°C, θ
JA
= 76°C/W
EXPOSED PAD (PIN 9) IS GND
MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3547BEDDB#PBF LTC3547BEDDB#TRPBF LCPD 8-Lead (3mm × 2mm) Plastic DFN –40°C to 85°C
LTC3547BEDDB-1#PBF LTC3547BEDDB-1#TRPBF LCPF 8-Lead (3mm × 2mm) Plastic DFN –40°C to 85°C
LTC3547BIDDB #PBF LTC3547BIDDB #TRPBF LCPD 8-Lead (3mm × 2mm) Plastic DFN –40°C to 125°C
Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. *Temperature grades are identifi ed by a label on the shipping container.
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/
PIN CONFIGURATION
LTC3547B
3
3547bfb
V
IN
(V)
2.5
100
90
80
70
60
50
40
10
20
30
45
3547b G02
3 3.5
4.5 5.5
EFFICIENCY (%)
V
OUT
= 1.8V
I
OUT
= 0.1mA
I
OUT
= 1mA
I
OUT
= 10mA
I
OUT
= 100mA
I
OUT
= 300mA
10μs/DIV
V
OUT
50mV/DIV
I
L
50mA/DIV
SW,
AC-COUPLED
5V/DIV
3547b G01
V
IN
= 3.6V
V
OUT
= 1.8V
I
LOAD
= 1mA
TEMPERATURE (ºC)
–50
400
350
300
250
200
150
100
25 75
3547b G03
–25 0
50 100
SUPPLY CURRENT (μA)
I
LOAD
= 0A
V
IN
= 5.5V
V
IN
= 2.7V
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
ΔV
LINEREG
Reference Voltage Line Regulation V
IN
= 2.5V to 5.5V 0.3 0.5 %/V
ΔV
LOADREG
Output Voltage Load Regulation I
LOAD
= 50mA to 300mA 0.5 %
I
S
Input DC Supply Current
Active Mode (Note 4)
Shutdown
V
FB1
= V
FB2
= 0.95 × V
FBREG
RUN1 = RUN2 = 0V, V
IN
= 5.5V
450
0.1
700
1
μA
μA
f
OSC
Oscillator Frequency V
FB
= 0.6V
●
1.8 2.25 2.7 MHz
I
LIM
Peak Switch Current Limit
Channel 1 (300mA)
Channel 2 (300mA)
V
IN
= 2.5V, V
FB
< V
FBREG
, Duty Cycle < 35%
400
400
550
550
mA
mA
R
DS(ON)
Channel 1 (Note 3)
Top Switch On-Resistance
Bottom Switch On-Resistance
Channel 2 (Note 3)
Top Switch On-Resistance
Bottom Switch On-Resistance
V
IN
= 3.6V, I
SW
= 100mA
V
IN
= 3.6V, I
SW
= 100mA
V
IN
= 3.6V, I
SW
= 100mA
V
IN
= 3.6V, I
SW
= 100mA
0.8
0.75
0.8
0.75
1.05
1.05
1.05
1.05
Ω
Ω
Ω
Ω
I
SW(LKG)
Switch Leakage Current V
IN
= 5V, V
RUN
= 0V 0.01 1 μA
t
SOFTSTART
Soft-Start Time V
FB
From 10% to 90% Full-Scale 0.450 0.650 0.850 ms
V
RUN
RUN Threshold High
●
0.4 1 1.2 V
I
RUN
RUN Leakage Current
●
0.01 1 μA
The ● denotes the specifi cations which apply over the full operating
temperature range, otherwise specifi cations are at T
A
= 25°C. V
CC
= 3.6V, unless otherwise noted.
ELECTRICAL CHARACTERISTICS
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 LTC3547BE is guaranteed to meet specifi ed performance
from 0°C to 85°C. Specifi cations over the –40°C and 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls. The LTC3547BI is guaranteed over the
–40°C to 125°C operating temperature range.
Note 3: The DFN switch on-resistance is guaranteed by correlation to
wafer level measurements.
Note 4: Dynamic supply current is higher due to the internal gate charge
being delivered at the switching frequency.
Note 5: Guaranteed by long-term current density limitations.
Note 6: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specifi ed maximum operating junction
temperature may impair device reliability.
Pulse Skip Mode Operation Effi ciency vs Input Voltage
Supply Current vs Temperature
TYPICAL PERFOR A CE CHARACTERISTICS
UW
T
A
= 25°C unless otherwise specifi ed.
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P16

LTC3547BEDDB-1#TRMPBF

Mfr. #:
Buy LTC3547BEDDB-1#TRMPBF
Manufacturer:
Analog Devices / Linear Technology
Description:
Switching Voltage Regulators Dual Monolithic 300mA Synch Step-Down Reg with fixed 1.2V & 1.8V outputs
Lifecycle:
New from this manufacturer.
Delivery:
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