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LTC3548IMSE#PBF

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P16
LTC3548
1
3548fc
TYPICAL APPLICATION
FEATURES
APPLICATIONS
DESCRIPTION
■
PDAs/Palmtop PCs
■
Digital Cameras
■
Cellular Phones
■
Portable Media Players
■
PC Cards
■
Wireless and DSL Modems
n
High Effi ciency: Up to 95%
n
Very Low Quiescent Current: Only 40μA
n
Low Output Ripple Burst Mode
®
Operation
n
2.25MHz Constant-Frequency Operation
n
High Switch Current: 0.7A and 1.2A
n
No Schottky Diodes Required
n
Low R
DS(ON)
Internal Switches: 0.35Ω
n
Current Mode Operation for Excellent Line
and Load Transient Response
n
Short-Circuit Protected
n
Low Dropout Operation: 100% Duty Cycle
n
Ultralow Shutdown Current: I
Q
< 1μA
n
Output Voltages from 5V down to 0.6V
n
Power-On Reset Output
n
Externally Synchronizable Oscillator
n
Small Thermally Enhanced MSOP and 3mm × 3mm
DFN Packages
Dual Synchronous,
400mA/800mA, 2.25MHz
Step-Down DC/DC Regulator
The LTC
®
3548 is a dual, constant-frequency, synchronous
step down DC/DC converter. Intended for low power ap-
plications, it operates from 2.5V to 5.5V input voltage
range and has a constant 2.25MHz switching frequency,
allowing the use of tiny, low cost capacitors and inductors
with a profi le ≤1mm. Each output voltage is adjustable
from 0.6V to 5V. Internal synchronous 0.35Ω, 0.7A/1.2A
power switches provide high effi ciency without the need
for external Schottky diodes.
A user selectable mode input is provided to allow the user
to trade-off noise ripple for low power effi ciency. Burst
Mode operation provides high effi ciency at light loads,
while pulse-skipping mode provides low noise ripple at
light loads.
To further maximize battery runtime, the P-channel
MOSFETs are turned on continuously in dropout (100%
duty cycle), and both channels draw a total quiescent cur-
rent of only 40μA. In shutdown, the device draws <1μA.
Figure 1. 2.5V/1.8V at 400mA/800mA Step-Down Regulators
RUN2 V
IN
V
IN
= 2.8V
TO 5.5V
V
OUT2
= 2.5V
AT 400mA
V
OUT1
= 1.8V
AT 800mA
RUN1
POR
SW1
V
FB1
GND
V
FB2
SW2
MODE/SYNC
LTC3548
10μF 100k
RESET
33pF68pF
2.2μH4.7μH
887k 604k
301k280k
4.7μF 10μF
3548 TA01
LOAD CURRENT (mA)
1
EFFICIENCY (%)
100
95
90
85
80
75
70
65
60
POWER LOSS (mW)
1000
100
10
1
0.1
10 100 1000
3548 TA02
V
IN
= 3.3V, V
OUT
= 1.8V
Burst Mode OPERATION
CHANNEL 1, NO LOAD ON CHANNEL 2
POWER LOSS
EFFICIENCY
LTC3548 Effi ciency Curve
L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners. Protected by U.S. Patents, including 5481178, 6127815, 6304066, 6498466, 6580258
6611131..
LTC3548
2
3548fc
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3548EDD#PBF LTC3548EDD#TRPBF LBNJ
10-Lead (3mm × 3mm) Plastic DFN
–40°C to 85°C
LTC3548IDD#PBF LTC3548IDD#TRPBF LBNJ
10-Lead (3mm × 3mm) Plastic DFN
–40°C to 85°C
LTC3548EMSE#PBF LTC3548EMSE#TRPBF LTBNH 10-Lead Plastic MSOP –40°C to 85°C
LTC3548IMSE#PBF LTC3548IMSE#TRPBF LTBNH 10-Lead Plastic MSOP –40°C to 85°C
Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is 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/
V
IN
Voltages .................................................–0.3V to 6V
V
FB1
, V
FB2
Voltages ...........................–0.3V to V
IN
+0.3V
RUN1, RUN2 Voltages ................................ –0.3V to V
IN
MODE/SYNC Voltage .......................–0.3V to V
IN
+ 0.3V
SW1, SW2 Voltage ...........................– 0.3V to V
IN
+ 0.3V
POR Voltage .................................................–0.3V to 6V
(Note 1)
Operating Temperature Range (Note 2)....–40°C to 85°C
Junction Temperature (Note 5) ............................. 125°C
Storage Temperature Range ...................– 65°C to 125°C
Lead Temperature (Soldering, 10 sec)
MSE Only .......................................................... 300°C
ABSOLUTE MAXIMUM RATINGS
PIN CONFIGURATION
ORDER INFORMATION
ELECTRICAL CHARACTERISTICS
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 specifi ed. (Note 2)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
IN
Operating Voltage Range
l
2.5 5.5 V
I
FB
Feedback Pin Input Current
l
30 nA
V
FB
Feedback Voltage (Note 3) 0°C ≤ T
A
≤ 85°C
–40°C ≤ T
A
≤ 85°C
l
0.588
0.585
0.6
0.6
0.612
0.612
V
V
ΔV
LINEREG
Reference Voltage Line Regulation V
IN
= 2.5V to 5.5V (Note 3) 0.3 0.5 %V
TOP VIEW
DD PACKAGE
10-LEAD (3mm s 3mm) PLASTIC DFN
10
11
9
6
7
8
4
5
3
2
1
V
FB2
RUN2
POR
SW2
MODE/
SYNC
V
FB1
RUN1
V
IN
SW1
GND
T
JMAX
= 125°C, θ
JA
= 45°C/W, θ
JC
= 3°C/W
EXPOSED PAD (PIN 11) IS PGND, MUST BE CONNECTED TO GND
(SOLDERED TO A 4-LAYER BOARD)
TOP VIEW
1
2
3
4
5
V
FB1
RUN1
V
IN
SW1
GND
10
9
8
7
6
V
FB2
RUN2
POR
SW2
MODE/
SYNC
11
MSE PACKAGE
10-LEAD PLASTIC MSOP
T
JMAX
= 125°C, θ
JA
= 45°C/W, θ
JC
= 10°C/W
EXPOSED PAD (PIN 11) IS PGND, MUST BE CONNECTED TO GND
(SOLDERED TO A 4-LAYER BOARD)
LTC3548
3
3548fc
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 LTC3548 is guaranteed to meet specifi ed performance from
0°C to 85°C. Specifi cations over the – 40°C to 85°C operating temperature
range are assured by design, characterization and correlation with
statistical process controls. The LTC3548I is guaranteed to meet specifi ed
performance over the full –40°C to 85°C temperature range.
Note 3: The LTC3548 is tested in a proprietary test mode that connects V
FB
to the output of the error amplifi er.
Note 4: Dynamic supply current is higher due to the internal gate charge
being delivered at the switching frequency.
Note 5: T
J
is calculated from the ambient T
A
and power dissipation P
D
according to the following formula: T
J
= T
A
+ (P
D
• θ
JA
).
Note 6: The DFN switch on-resistance is guaranteed by correlation to
wafer level measurements.
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 specifi ed. (Note 2)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
ΔV
LOADREG
Output Voltage Load Regulation (Note 3) 0.5 %
I
S
Input DC Supply Current
Active Mode
Sleep Mode
Shutdown
(Note 4)
V
FB1
= V
FB2
= 0.5V
V
FB1
= V
FB2
= 0.63V, MODE/SYNC = 3.6V
RUN = 0V, V
IN
= 5.5V, MODE/SYNC = 0V
700
40
0.1
950
60
1
μA
μA
μA
f
OSC
Oscillator Frequency V
FB
= 0.6V
l
1.8 2.25 2.7 MHz
f
SYNC
Synchronization Frequency 2.25 MHz
I
LIM
Peak Switch Current Limit Channel 1
Peak Switch Current Limit Channel 2
V
IN
= 3V, V
FB
= 0.5V, Duty Cycle <35%
V
IN
= 3V, V
FB
= 0.5V, Duty Cycle <35%
0.95
0.6
1.2
0.7
1.6
0.9
A
A
R
DS(ON)
Top Switch On-Resistance
Bottom Switch On-Resistance
(Note 6)
(Note 6)
0.35
0.30
0.45
0.45
Ω
Ω
I
SW(LKG)
Switch Leakage Current V
IN
= 5V, V
RUN
= 0V, V
FB
= 0V 0.01 1 μA
POR Power-On Reset Threshold V
FB
Ramping Down, MODE/SYNC = 0V –8.5 %
Power-On Reset On-Resistance 100 200 Ω
Power-On Reset Delay 262,144 Cycles
V
RUN
RUN Threshold
l
0.3 1 1.5 V
I
RUN
RUN Leakage Current
l
0.01 1 μA
MODE Mode Threshold Low
Mode Threshold High
0
V
IN
– 0.5
0.5
V
IN
V
V
TYPICAL PERFORMANCE CHARACTERISTICS
T
A
= 25°C unless otherwise specifi ed.
Load Step
Burst Mode Operation Pulse-Skipping Mode
3548 G01
V
IN
= 3.6V
V
OUT
= 1.8V
I
LOAD
= 180mA
CHANNEL 1; CIRCUIT OF FIGURE 3
SW
5V/DIV
V
OUT
20mV/DIV
I
L
200mA/DIV
2μs/DIV
3548 G02
V
IN
= 3.6V
V
OUT
= 1.8V
I
LOAD
= 30mA
CHANNEL 1; CIRCUIT OF FIGURE 3
SW
5V/DIV
V
OUT
10mV/DIV
I
L
200mA/DIV
1μs/DIV
3548 G03
V
IN
= 3.6V
V
OUT
= 1.8V
I
LOAD
= 80mA TO 800mA
CHANNEL 1; CIRCUIT OF FIGURE 3
V
OUT
200mV/DIV
I
L
500mA/DIV
I
LOAD
500mA/DIV
20μs/DIV
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P16

LTC3548IMSE#PBF

Mfr. #:
Buy LTC3548IMSE#PBF
Manufacturer:
Analog Devices / Linear Technology
Description:
Switching Voltage Regulators Dual, Sync. 800mA/400mA, 2.25MHz Step Down in DFN
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
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