step-down converter using a current mode architecture
capable of supplying 300mA of output current.
The LTC3103 offers two operational modes: automatic
Burst Mode operation and forced continuous mode allow-
ing the user the ability to optimize output voltage ripple,
noise and light load efficiency. With Burst Mode operation
enabled, the typical DC input supply current at no load
drops to 1.8µA maximizing the efficiency for light loads.
Selection of forced continuous mode provides very low
noise constant frequency, 1.2MHz operation.
Additionally, the LTC3103 includes an accurate RUN com-
parator, thermal overload protection, a power good output
and an integrated soft-start feature to guarantee that the
power system start-up is well controlled.
L,
LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners.
n
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n
n
Ultralow Quiescent Current: 1.8µA
Synchronous Rectification: Efficiency Up to 95%
Wide V
IN
Range: 2.5V to 15V
Wide V
OUT
Range: 0.6V to 13.8V
300mA Output Current
User-Selectable Automatic Burst Mode
®
or Forced
Continuous Operation
Accurate and Programmable RUN Pin Threshold
1.2MHz Fixed Frequency PWM
Internal Compensation
Power Good Status Output for V
OUT
Available in Thermally Enhanced 3mm
×
3mm
×
0.75mm, 10-Pin DFN and 10-Pin MSOP Packages
APPLICATIONS
n
n
n
n
n
n
Remote Sensor Networks
Distributed Power Systems
Multicell Battery or SuperCap Regulator
Energy Harvesters
Portable Instruments
Low Power Wireless Systems
TYPICAL APPLICATION
100
3V TO 15V
V
IN
MODE
BST
SW
0.022µF
10µH
95
2.2V
300mA
EFFICIENCY (%)
90
85
80
75
70
65
60
3103 TA01a
Efficiency vs Output Current
100
LTC3103
10µF
RUN PGOOD
V
CC
GND
1µF
FB
1.78M
27pF
POWER LOSS (mW)
10
47µF
665k
1
V
IN
= 3V
V
IN
= 5V
V
IN
= 10V
V
IN
= 15V
0.01
0.1
0.001
OUTPUT CURRENT (A)
1
3103 TA01b
55
50
0.0001
0.1
3103fa
For more information
www.linear.com/LTC3103
1
LTC3103
ABSOLUTE MAXIMUM RATINGS
(Note 1)
V
IN
............................................................. –0.3V to 18V
SW ................................................ –0.3V to (V
IN
+ 0.3V)
FB ................................................................ –0.3V to 6V
BST ........................................ (SW – 0.3V) to (SW + 6V)
RUN, MODE ............................................... –0.3V to V
IN
V
CC
, PGOOD ................................................. –0.3V to 6V
Operating Junction Temperature Range
(Notes 2, 3) ............................................ –40°C to 125°C
Storage Temperature Range .................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)
MSE Only .......................................................... 300°C
PIN CONFIGURATION
TOP VIEW
V
IN
SW
BST
GND
PGOOD
1
2
3
4
5
11
GND
10 MODE
9 NC
8 FB
7 RUN
6 V
CC
TOP VIEW
V
IN
SW
BST
GND
PGOOD
1
2
3
4
5
11
GND
10
9
8
7
6
MODE
NC
FB
RUN
V
CC
DD PACKAGE
10-LEAD (3mm
×
3mm) PLASTIC DFN
T
JMAX
= 125°C,
θ
JA
= 58°C/W,
θ
JC
= 10°C/W
EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
MSE PACKAGE
10-LEAD PLASTIC MSOP
T
JMAX
= 125°C,
θ
JA
= 40°C/W,
θ
JC
= 5.0°C/W
EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LTC3103EDD#PBF
LTC3103IDD#PBF
LTC3103EMSE#PBF
LTC3103IMSE#PBF
TAPE AND REEL
LTC3103EDD#TRPBF
LTC3103IDD#TRPBF
LTC3103EMSE#TRPBF
LTC3103IMSE#TRPBF
http://www.linear.com/product/LTC3103#orderinfo
PART MARKING*
LFXH
LFXH
LTFXJ
LTFXJ
PACKAGE DESCRIPTION
10-Lead (3mm
×
3mm) Plastic DFN
10-Lead (3mm
×
3mm) Plastic DFN
10-Lead Plastic MSOP
10-Lead Plastic MSOP
TEMPERATURE RANGE
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
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/.
Some packages are available in 500 unit reels through
designated sales channels with #TRMPBF suffix.
ELECTRICAL CHARACTERISTICS
PARAMETER
Step-Down Converter
Input Voltage Range
Input Undervoltage Lockout Threshold
Input Undervoltage Lockout Hysteresis
After Start-Up
CONDITIONS
The
l
denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2). V
IN
= 10V unless otherwise noted.
MIN
l
l
l
TYP
MAX
15
UNITS
V
V
V
V
V
3103fa
2.6
2.5
2.1
2.1
0.4
V
IN
Rising
V
IN
Rising, T
J
= 0°C to 85°C (Note 4)
(Note 4)
2.6
2.5
2
For more information
www.linear.com/LTC3103
LTC3103
ELECTRICAL CHARACTERISTICS
PARAMETER
Feedback Voltage
Feedback Voltage Line Regulation
Feedback Input Current
Oscillator Frequency
Quiescent Current, V
IN
—Active
Quiescent Current, V
IN
— Sleep
Quiescent Current, V
IN
—Shutdown
N-Channel MOSFET Synchronous Rectifier
Leakage Current
N-Channel MOSFET Switch Leakage Current
N-Channel MOSFET Synchronous
Rectifier R
DS(ON)
N-Channel MOSFET Switch R
DS(ON)
Peak Current Limit
PGOOD Threshold
PGOOD Hysteresis
PGOOD Voltage Low
PGOOD Leakage Current
Maximum Duty Cycle
Switch Minimum Off Time (t
OFF(MIN)
)
Synchronous Rectifier Minimum On Time
(t
ON(MIN)
)
RUN Pin Threshold
RUN Pin Hysteresis
RUN Input Current
MODE Threshold
MODE Input Current
Soft-Start Time
MODE = 1.2V
V
IN
= 5V
0.7
RUN = 1.2V
l
l
The
l
denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2). V
IN
= 10V unless otherwise noted.
CONDITIONS
(Note 5)
V
IN
= 2.5V to 15V (Note 5)
(Note 5)
T
J
= 0°C to 85°C (Note 4)
RUN = V
IN
, MODE = 0V, FB > 0.612 Nonswitching
RUN = V
IN
, FB > 0.612, MODE = V
IN
, T
J
= 0°C to 85°C (Note 4)
RUN = V
IN
, FB > 0.612, MODE = V
IN
RUN = 0V, T
J
= 0°C to 85°C (Note 4)
RUN = 0V
V
IN
= V
SW
= 15V, V
RUN
= 0V
V
IN
= 15V, V
SW
= 0V, V
RUN
= 0V
I
SW
= 200mA
I
SW
= –200mA
l
l
l
l
l
l
MIN
0.588
TYP
0.6
0.02
1
MAX
0.612
0.05
20
1.55
1.45
2.6
3.3
1.7
3.3
0.3
0.3
UNITS
V
%/V
nA
MHz
MHz
µA
µA
µA
µA
µA
µA
µA
Ω
Ω
0.930
1
1.2
1.2
600
1.8
1.8
1
1.8
0.01
0.01
0.85
0.65
0.40
–14
0.50
–10
2
0.2
0.01
0.75
–5
A
%
%
V
FB Falling, Percentage Below FB
Percentage of FB
I
PGOOD
= 100µA
V
PGOOD
= 5V
l
0.3
µA
%
ns
ns
89
92
65
70
(Note 4)
(Note 4)
RUN Pin Rising
l
0.76
0.80
0.06
0.01
0.85
0.4
1.2
4
2.5
V
V
µA
V
µA
ms
0.5
0.8
0.1
1.4
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 LTC3103 is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTC3103E is guaranteed to meet specifications from
0°C to 85°C junction temperature. Specifications over the –40°C to
125°C operating junction temperature range are assured by design,
characterization and correlation with statistical process controls. The
LTC3103I is guaranteed over the full –40°C to 125°C operating junction
temperature range. The junction temperature (T
J
) is calculated from the
ambient temperature (T
A
) and power dissipation (P
D
) according to the
formula:
T
J
= T
A
+ (P
D
)(θ
JA
°C/W)
where
θ
JA
is the package thermal impedance. Note the maximum ambient
temperature consistent with these specifications is determined by specific
operating conditions in conjunction with board layout, the rated package
thermal resistance and other environmental factors.
Note 3:
This IC includes overtemperature protection that is intended to
protect the device during momentary overload conditions. The maximum
rated junction temperature will be exceeded when this protection is active.
Continuous operation above the specified absolute maximum operating
junction temperature may impair device reliability or permanently damage
the device.
Note 4:
Specification is guaranteed by design.
Note 5:
The LTC3103 has a proprietary test mode that allows testing in a
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