step-down converter using a current mode architecture
capable of supplying 300mA of output current. The LTC3104
includes an integrated, adjustable 10mA LDO to power
noise sensitive functions.
The LTC3104 offers two operational modes: automatic
Burst Mode operation and forced continuous mode allow-
ing the user 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
2.6µA, maximizing the efficiency for light loads. Selec-
tion of forced continuous mode provides very low noise
constant frequency, 1.2MHz operation.
Additionally, the LTC3104 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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Ultralow Quiescent Current: 2.6µA
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
10mA Adjustable LDO
Available in Thermally Enhanced 3mm
×
4mm
×
0.75mm, 14-Pin DFN and 16-Pin MSOP Packages
APPLICATIONS
n
n
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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
ON
OFF
V
IN
RUN
LTC3104
ON
OFF
FB
RUNLDO PGOOD
MODE
10µF
V
CC
1µF
GND
V
INLDO
V
LDO
FBLDO
825k
412k
665k
BST
SW
1.78M
12pF
47µF
22nF 10µH
95
2.2V
300mA
EFFICIENCY (%)
90
85
80
75
70
65
60
55
50
0.0001
Efficiency vs Output Current
100
POWER LOSS (mW)
10
1.8V
10mA
4.7µF
3104 TA01a
1
V
IN
= 3V
V
IN
= 5V
V
IN
= 10V
V
IN
= 15V
0.01
0.1
0.001
OUTPUT CURRENT (A)
1
3104 TA01b
0.1
3104f
1
LTC3104
ABSOLUTE MAXIMUM RATINGS
(Note 1)
V
IN
............................................................. –0.3V to 18V
SW ................................................ –0.3V to (V
IN
+ 0.3V)
FB, FBLDO.................................................... –0.3V to 6V
BST ........................................ (SW – 0.3V) to (SW + 6V)
V
INLDO
........................................................ –0.3V to 17V
V
LDO
........................................................... –0.3V to 17V
RUN, MODE, RUNLDO ............................... –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
MODE
V
IN
SW
BST
GND
RUNLDO
PGOOD
1
2
3
4
5
6
7
15
GND
14 V
INLDO
13 V
LDO
12 FBLDO
11 FB
10 RUN
9 V
CC
8 NC
TOP VIEW
NC
MODE
V
IN
SW
BST
GND
RUNLDO
PGOOD
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
NC
V
INLDO
V
LDO
FBLDO
FB
RUN
V
CC
NC
17
GND
DE PACKAGE
14-LEAD (4mm
×
3mm) PLASTIC DFN
T
JMAX
= 125°C,
θ
JA
= 53°C/W,
θ
JC
= 10°C/W
EXPOSED PAD (PIN 15) IS GND, MUST BE SOLDERED TO PCB
MSE PACKAGE
16-LEAD PLASTIC MSOP
T
JMAX
= 125°C,
θ
JA
= 40°C/W,
θ
JC
= 10°C/W
EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LTC3104EDE#PBF
LTC3104IDE#PBF
LTC3104EMSE#PBF
LTC3104IMSE#PBF
TAPE AND REEL
LTC3104EDE#TRPBF
LTC3104IDE#TRPBF
LTC3104EMSE#TRPBF
LTC3104IMSE#TRPBF
PART MARKING*
3104
3104
3104
3104
PACKAGE DESCRIPTION
14-Lead (4mm
×
3mm) Plastic DFN
14-Lead (4mm
×
3mm) Plastic DFN
16-Lead Plastic MSOP
16-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.
Consult LTC Marketing for information on non-standard lead based finish parts.
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/
3104f
2
LTC3104
ELECTRICAL CHARACTERISTICS
PARAMETER
Step-Down Converter
Input Voltage Range
Input Undervoltage Lockout Threshold
Input Undervoltage Lockout Hysteresis
Feedback Voltage
Feedback Voltage Line Regulation
Feedback Input Current
Oscillator Frequency
Quiescent Current, V
IN
—Active
Quiescent Current, V
IN
—Sleep
V
IN
Rising
V
IN
Rising, T
J
= 0°C to 85°C (Note 4)
(Note 4)
(Note 5)
V
IN
= 2.5V to 15V (Note 5)
(Note 5)
T
J
= 0°C to 85°C (Note 4)
RUN = V
IN
, RUNLDO = V
IN
, MODE = 0V,
FB > 0.612, Nonswitching
T
J
= 0°C to 85°C, RUN = MODE = V
IN
, FB > 0.612
RUNLDO = V
IN
(Note 4)
RUNLDO = 0V (Note 4)
RUN = MODE = V
IN
, FB > 0.612
RUNLDO = V
IN
RUNLDO = 0V
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)
)
RUN Pin Threshold
RUN Pin Hysteresis
RUN Input Current
MODE Threshold
MODE Input Current
Soft-Start Time
LDO Regulator
LDO Input Voltage Range (V
IN(LDO)
)
LDO Output Voltage Range (V
LDO
)
LDO Feedback Voltage
LDO Feedback Input Current
I
LDO
= 1mA
l
l
l
l
l
l
l
l
l
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
= V
INLDO
= 10V unless otherwise noted.
CONDITIONS
MIN
2.5
2.1
2.1
0.4
0.588
0.6
0.02
1
0.93
1.0
1.2
1.2
600
0.612
0.05
20
1.55
1.45
TYP
MAX
15
2.6
2.5
UNITS
V
V
V
V
V
%/V
nA
MHz
MHz
µA
2.6
1.8
2.8
1.8
1
1
0.01
0.01
0.85
0.65
l
3.3
2.6
5.5
4.5
1.7
3.3
0.3
0.3
µA
µA
µA
µA
µA
µA
µA
µA
Ω
Ω
RUN = 0V, RUNLDO = 0V, T
J
= 0°C to 85°C (Note 4)
RUN = 0V, RUNLDO = 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
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)
RUN Pin Rising
RUN = 1.2V
MODE = 1.2V
0.7
2.5
0.6
0.576
l
Synchronous Rectifier Minimum On Time (t
ON(MIN)
) (Note 4)
0.76
0.8
0.06
0.01
0.85
0.4
1.2
4
2.5
15
14.5
V
V
µA
V
µA
ms
V
V
V
nA
3104f
l
l
0.5
0.8
0.1
1.4
0.6
1
0.624
20
3
LTC3104
ELECTRICAL CHARACTERISTICS
PARAMETER
Dropout Voltage (V
DO
)
Output Current
Output Current—Short Circuit
Quiescent Current, V
INLDO
Line Regulation
Load Regulation
RUNLDO Threshold
RUNLDO Input Current
RUNLDO = 1.2V
V
LDO
= 0V
V
IN
= V
INLDO
= RUNLDO = 10V
V
INLDO
= 2.5V to 15V, I
LDO
= 1mA
I
LDO
= 1mA to 10mA
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
= V
INLDO
= 10V unless otherwise noted.
CONDITIONS
I
LDO
= 10mA
l
l
MIN
10
15
TYP
150
20
0.3
0.1
0.75
MAX
UNITS
mV
mA
mA
µA
%
%
0.5
0.8
0.01
1.2
0.3
V
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 LTC3104 is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTC3104E 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
LTC3104I 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 LTC3104 has a proprietary test mode that allows testing in a
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