LTC3103
1
3103fa
For more information www.linear.com/LTC3103
TYPICAL APPLICATION
FEATURES DESCRIPTION
1.8µA Quiescent Current,
15V, 300mA Synchronous
Step-Down DC/DC
Converter
The LT C
®
3103 is a high efficiency, monolithic synchronous
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.
APPLICATIONS
n Ultralow Quiescent Current: 1.8µA
n Synchronous Rectification: Efficiency Up to 95%
n Wide VIN Range: 2.5V to 15V
n Wide VOUT Range: 0.6V to 13.8V
n 300mA Output Current
n User-Selectable Automatic Burst Mode
®
or Forced
Continuous Operation
n Accurate and Programmable RUN Pin Threshold
n 1.2MHz Fixed Frequency PWM
n Internal Compensation
n Power Good Status Output for VOUT
n Available in Thermally Enhanced 3mm × 3mm ×
0.75mm, 10-Pin DFN and 10-Pin MSOP Packages
n Remote Sensor Networks
n Distributed Power Systems
n Multicell Battery or SuperCap Regulator
n Energy Harvesters
n Portable Instruments
n Low Power Wireless Systems
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.
VIN 0.022µF
BST
3V TO 15V
MODE SW
RUN PGOOD
VCC FB
LTC3103
GND
665k
10µH 2.2V
300mA
3103 TA01a
47µF
1µF
10µF 1.78M
27pF
Efficiency vs Output Current
OUTPUT CURRENT (A)
65
EFFICIENCY (%)
POWER LOSS (mW)
95
100
60
55
90
75
85
80
70
0.0001 0.01 0.1 1
3103 TA01b
50 0.1
1
10
100
0.001
VIN = 3V
VIN = 5V
VIN = 10V
VIN = 15V
LTC3103
2
3103fa
For more information www.linear.com/LTC3103
ABSOLUTE MAXIMUM RATINGS
VIN ............................................................. –0.3V to 18V
SW ................................................ –0.3V to (VIN + 0.3V)
FB ................................................................ –0.3V to 6V
BST ........................................ (SW – 0.3V) to (SW + 6V)
RUN, MODE ............................................... –0.3V to VIN
VCC, PGOOD ................................................. –0.3V to 6V
(Note 1)
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3103EDD#PBF LTC3103EDD#TRPBF LFXH 10-Lead (3mm × 3mm) Plastic DFN –40°C to 125°C
LTC3103IDD#PBF LTC3103IDD#TRPBF LFXH 10-Lead (3mm × 3mm) Plastic DFN –40°C to 125°C
LTC3103EMSE#PBF LTC3103EMSE#TRPBF LTFXJ 10-Lead Plastic MSOP –40°C to 125°C
LTC3103IMSE#PBF LTC3103IMSE#TRPBF LTFXJ 10-Lead Plastic MSOP –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
The l denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at TA = 25°C (Note 2). VIN = 10V unless otherwise noted.
TOP VIEW
11
GND
DD PACKAGE
10-LEAD (3mm × 3mm) PLASTIC DFN
10
9
6
7
8
4
5
3
2
1
MODE
NC
FB
RUN
VCC
VIN
SW
BST
GND
PGOOD
TJMAX = 125°C, θJA = 58°C/W, θJC = 10°C/W
EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
1
2
3
4
5
VIN
SW
BST
GND
PGOOD
10
9
8
7
6
MODE
NC
FB
RUN
VCC
TOP VIEW
11
GND
MSE PACKAGE
10-LEAD PLASTIC MSOP
TJMAX = 125°C, θJA = 40°C/W, θJC = 5.0°C/W
EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
PIN CONFIGURATION
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
PARAMETER CONDITIONS MIN TYP MAX UNITS
Step-Down Converter
Input Voltage Range
After Start-Up
l
l
2.6
2.5
15 V
V
Input Undervoltage Lockout Threshold VIN Rising
VIN Rising, TJ = 0°C to 85°C (Note 4)
l2.1
2.1
2.6
2.5
V
V
Input Undervoltage Lockout Hysteresis (Note 4) 0.4 V
http://www.linear.com/product/LTC3103#orderinfo
LTC3103
3
3103fa
For more information www.linear.com/LTC3103
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at TA = 25°C (Note 2). VIN = 10V unless otherwise noted.
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
TJ ≈ TA. 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 (TJ) is calculated from the
ambient temperature (TA) and power dissipation (PD) according to the
formula:
TJ = TA + (PD)(θJA°C/W)
where θJA 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
feedback loop which servos VFB to the balance point for the error amplifier.
PARAMETER CONDITIONS MIN TYP MAX UNITS
Feedback Voltage (Note 5) l0.588 0.6 0.612 V
Feedback Voltage Line Regulation VIN = 2.5V to 15V (Note 5) 0.02 0.05 %/V
Feedback Input Current (Note 5) l1 20 nA
Oscillator Frequency
TJ = 0°C to 85°C (Note 4)
l0.930
1
1.2
1.2
1.55
1.45
MHz
MHz
Quiescent Current, VIN—Active RUN = VIN, MODE = 0V, FB > 0.612 Nonswitching 600 µA
Quiescent Current, VIN— Sleep RUN = VIN, FB > 0.612, MODE = VIN, TJ = 0°C to 85°C (Note 4)
RUN = VIN, FB > 0.612, MODE = VIN
l
1.8
1.8
2.6
3.3
µA
µA
Quiescent Current, VIN—Shutdown RUN = 0V, TJ = 0°C to 85°C (Note 4)
RUN = 0V
l
1
1.8
1.7
3.3
µA
µA
N-Channel MOSFET Synchronous Rectifier
Leakage Current
VIN = VSW = 15V, VRUN = 0V 0.01 0.3 µA
N-Channel MOSFET Switch Leakage Current VIN = 15V, VSW = 0V, VRUN = 0V 0.01 0.3 µA
N-Channel MOSFET Synchronous
Rectifier RDS(ON)
ISW = 200mA 0.85 Ω
N-Channel MOSFET Switch RDS(ON) ISW = –200mA 0.65 Ω
Peak Current Limit l0.40 0.50 0.75 A
PGOOD Threshold FB Falling, Percentage Below FB –14 –10 –5 %
PGOOD Hysteresis Percentage of FB 2 %
PGOOD Voltage Low IPGOOD = 100µA 0.2 V
PGOOD Leakage Current VPGOOD = 5V 0.01 0.3 µA
Maximum Duty Cycle l89 92 %
Switch Minimum Off Time (tOFF(MIN)) (Note 4) 65 ns
Synchronous Rectifier Minimum On Time
(tON(MIN))
(Note 4) 70 ns
RUN Pin Threshold RUN Pin Rising l0.76 0.80 0.85 V
RUN Pin Hysteresis 0.06 V
RUN Input Current RUN = 1.2V l0.01 0.4 µA
MODE Threshold l0.5 0.8 1.2 V
MODE Input Current MODE = 1.2V 0.1 4 µA
Soft-Start Time VIN = 5V 0.7 1.4 2.5 ms
LTC3103
4
3103fa
For more information www.linear.com/LTC3103
TYPICAL PERFORMANCE CHARACTERISTICS
Efficiency vs Output Current
Efficiency vs Input Voltage
(Automatic Burst Mode Operation)
Application No-Load Input Current
vs Supply Voltage (Automatic
Burst Mode Operation)
TA = 25°C unless otherwise noted
OUTPUT CURRENT (A)
65
EFFICIENCY (%)
95
100
60
55
90
75
85
80
70
0.0001 0.01 0.1 1
3103 G01
50
0.001
VIN = 4V
VIN = 7V
VIN = 10V
VIN = 15V
VOUT = 3.3V
L = 15µH
INPUT VOLTAGE (V)
2
EFFICIENCY (%)
95
8
3103 G02
80
70
4 6 10
65
50
60
55
100
90
85
75
12 14 16
VOUT = 2.2V
L = 10µH
ILOAD = 300mA
ILOAD = 100mA
ILOAD = 10mA
ILOAD = 1mA
ILOAD = 100µA
INPUT VOLTAGE (V)
0
1.6
INPUT CURRENT (µA)
1.9
1.8
1.7
2.0
2.1
2.2
2 4 6 8
3103 G03
10 12 14 16 18
FRONT PAGE APPLICATION
Efficiency vs Output Current
(Forced Continuous Operation)
Efficiency vs Input Voltage
(Forced Continuous Operation)
Feedback Voltage
vs Temperature
Oscillator Frequency
vs Temperature RDS(ON) vs Temperature
Application No-Load Input Current
vs Supply Voltage (Forced
Continuous Operation)
OUTPUT CURRENT (A)
30
EFFICIENCY (%)
90
100
20
10
80
50
70
60
40
0.0001 0.01 0.1 1
3103 G04
0
0.001
VIN = 3.7V
VIN = 5V
VIN = 7V
VIN = 10V
VIN = 15V
VOUT = 3.3V
L = 10µH
INPUT VOLTAGE (V)
3
0
EFFICIENCY (%)
10
30
40
50
100
70
711 13 15
3103 G05
20
80
90
60
5 9
VOUT = 3.3V, L = 10µH
ILOAD = 300mA
ILOAD = 100mA
ILOAD = 10mA
ILOAD = 1mA
INPUT VOLTAGE (V)
2
2.0
2.5
3.5
8 12
3103 G06
1.5
1.0
4 6 10 14 16
0.5
0
3.0
INPUT CURRENT (mA)
FRONT PAGE APPLICATION
TEMPERATURE (°C)
–60
FB
0.25
0.50
100
0
–0.25
–0.50 –20–40 200 60 80 120
40
NORMALIZED TO 25°C
TEMPERATURE (°C)
–50
–10
FREQUENCY CHANGE (%)
–8
–4
–2
0
10
4
050 75
3103 G08
–6
6
8
2
–25 25 100 125
150
NORMALIZED TO 25°C
TEMPERATURE (°C)
–50
CHANGE IN RESISTANCE (%)
40
25
3103 G09
10
–10
–25 0 50
–20
–30
50
30
20
0
75 100
125
NORMALIZED TO 25°C
VIN = 10V
SYNCHRONOUS
RECTIFIER MAIN
SWITCH
LTC3103
5
3103fa
For more information www.linear.com/LTC3103
TYPICAL PERFORMANCE CHARACTERISTICS
TA = 25°C unless otherwise noted
Application No-Load Input Current
vs Temperature (Automatic Burst
Mode Operation)
SW Leakage vs Temperature
Peak Current Limit Change
vs Temperature
TEMPERATURE (°C)
–50
LEAKAGE CURRENT (nA)
350
25
3103 G10
200
100
–25 0 50
50
0
400
300
250
150
75 100
150
125
VIN = 10V
MAIN
SWITCH
SYNCHRONOUS
RECTIFIER
TEMPERATURE (°C)
–50
PEAK CURRENT LIMIT CHANGE (%)
–2.5
0
2.5
40 100
3103 G11
–5.0
–7.5
–10.0 –20 10 70
5.0
7.5
10.0
130
TEMPERATURE (°C)
–50
INPUT CURRENT (µA)
2.2
2.6
110
3103 G12
1.8
1.6
1.0 –10 30 70
–30 10 50 90
3.0
2.0
2.4
1.4
1.2
2.8
VIN = 10V
VOUT = 2.5V
Automatic Burst Mode Operation Forced Continuous Operation
Start-Up into Pre-Biased Output
(Automatic Burst Mode Operation)
Start-Up into Pre-Biased Output
(Forced Continuous Operation)
Start-Up from Shutdown
(Automatic Burst Mode Operation)
VOUT
20mV/DIV
AC-COUPLED
IL
100mA/DIV
1µs/DIV
3103 G14
ILOAD = 25mA
VIN = 10V
CIN = 10µF
L = 10µH
VOUT = 2.5V
C
OUT
= 22µF
RUN
5V/DIV
VOUT
1V/DIV
PGOOD
5V/DIV
IL
100mA/DIV
500µs/DIV
3103 G15
ILOAD = 2mA
VIN = 10V
CIN = 10µF
L = 10µH
VOUT = 2.5V
C
OUT
= 47µF
BURST CURRENT
PULSES
SOFT-START
PERIOD
VBST REFRESH
CURRENT PULSES
RUN
5V/DIV
VOUT
1V/DIV
IL
100mA/DIV
PGOOD
5V/DIV
500µs/DIV
3103 G16
ILOAD = 2mA
VIN = 10V
L = 10µH
V
OUT
= 2.5V
VBST REFRESH
CURRENT PULSES
RUN
5V/DIV
PGOOD
5V/DIV
VOUT
1V/DIV
IL
100mA/DIV
500µs/DIV
3103 G17
ILOAD = 25mA
VIN = 10V
L = 10µH
V
OUT
= 2.5V
Start-Up from Shutdown
(Forced Continuous Operation)
RUN
5V/DIV
VOUT
1V/DIV
IL
100mA/DIV
500µs/DIV
3103 G18
ILOAD = 5mA
VIN = 10V
L = 10µH
V
OUT
= 2.5V
SOFT-START
FOLDBACK PERIOD
C
OUT
= 100µF
C
OUT
= 47µF
V
IN
= 10V
C
IN
= 10µF
L = 10µH
V
OUT
= 2.2V
50µs/DIV
V
OUT
20mV/DIV
V
OUT
20mV/DIV
3103 G13
LTC3103
6
3103fa
For more information www.linear.com/LTC3103
TYPICAL PERFORMANCE CHARACTERISTICS
TA = 25°C unless otherwise noted
Automatic Burst Mode Threshold
vs Supply Voltage
Load Step
(Automatic Burst Mode Operation)
Load Step
(Forced Continuous Operation)
Load Regulation
(Automatic Burst Mode Operation)
Load Regulation
(Automatic Burst Mode Operation)
Load Regulation
(Automatic Burst Mode Operation)
Maximum Duty Cycle
vs Input Voltage
Minimum Input Voltage at
Maximum Duty Cycle vs Load
Current
Minimum Input Voltage at
Maximum Duty Cycle vs Load
Current
V
OUT
200mV/DIV
AC-COUPLED
IL
200mA/DIV
ILOAD
200mA/DIV
200µs/DIV
3103 G19
ILOAD = LOAD STEP, 5mA TO 300mA
VIN = 10V
CIN = 10µF
L = 10µH
VOUT = 2.2V
COUT = 47µF
V
OUT
50mV/DIV
AC-COUPLED
IL
100mA/DIV
ILOAD
100mA/DIV
200µs/DIV
3103 G20
ILOAD = LOAD STEP, 50mA TO 200mA
VIN = 10V
L = 10µH
VOUT = 2.5V
C
OUT
= 22µF
INPUT VOLTAGE (V)
0
0
BURST THRESHOLD (I
LOAD
, mA)
20
60
80
100
140
4810
3103 G27
40
160
120
2 6 12 14 16
VOUT = 1.2V
VOUT = 1.8V
VOUT = 2.5V
VOUT = 3.3V
VOUT = 5V
LOAD CURRENT (mA)
0
2.5
INPUT VOLTAGE (V)
3.0
3.5
4.0
4.5
5.5
50 100 150 200
3103 G21
250
300
5.0
VOUT = 4.2V
VOUT = 3.3V
VOUT = 2.5V
VOUT = 2.2V
VOUT = 1.8V
VOUT = 1.5V
LOAD CURRENT (mA)
0
5
INPUT VOLTAGE (V)
7
9
11
50 100 150 200
3103 G22
250
13
15
6
8
10
12
14
300
VOUT = 12V
VOUT = 9V
VOUT = 5V
ILOAD (mA)
0
–2.0
CHANGE IN V
OUT
(%)
–1.5
–1.0
–0.5
0
0.5
1.0
10 20 30 40
3103 G23
50
NORMALIZED AT ILOAD = 100mA
VIN = 10V
VOUT = 5V
CFF = 12pF
COUT = 68µF
COUT = 47µF
COUT = 22µF
ILOAD (mA)
0
–2.0
CHANGE IN V
OUT
(%)
–1.5
–1.0
–0.5
0
20 40 60 80
3103 G24
0.5
1.0
10 30 50 70
NORMALIZED AT ILOAD = 100mA
VIN = 10V
VOUT = 3.3V
CFF = 12pF
COUT = 68µF
COUT = 47µF
COUT = 33µF
ILOAD (mA)
0
CHANGE IN V
OUT
(%)
–1.5
–1.0
–0.5
60 100
3103 G25
–2.0
–2.5
–3.0 20 40 80
0
0.5
1.0
NORMALIZED AT ILOAD = 100mA
VIN = 10V
VOUT = 1.8V
CFF = 12pF
COUT = 100µF
COUT = 68µF
COUT = 47µF
INPUT VOLTAGE (V)
2
85
90
100
5 7
3103 G26
80
75
3 4 6 8 9
70
65
95
MAXIMUM DUTY CYCLE (%)
IOUT = 1mA
IOUT = 300mA
LTC3103
7
3103fa
For more information www.linear.com/LTC3103
PIN FUNCTIONS
VIN (Pin 1): Main Supply Pin. Decouple with a 10µF or
larger ceramic capacitor. The capacitor should be as close
to the part as possible.
SW (Pin 2): Switch Pin Connects to the Inductor. This pin
connects to the drains of the internal main and synchronous
power MOSFET switches.
BST (Pin 3): Bootstrapped Floating Supply for the High
Side Gate Drive. Connect to SW through a 22nF (minimum)
capacitor. The capacitor must be connected between BST
and SW and be located as close as possible to the part
as possible.
GND (Pin 4): Power Ground.
PGOOD (Pin 5): Open-drain output that is pulled to ground
when the feedback voltage falls 10% (typical) below the
regulation point, during a thermal shutdown event or if
the converter is disabled. The PGOOD output is valid 1ms
after the buck converter is enabled.
VCC (Pin 6): Internally Regulated Supply Rail. Internal
power rail regulated off of VIN to power control circuitry.
Decouple with a 1µF or larger ceramic capacitor placed
as close to the part as possible.
RUN (Pin 7): Run Pin Comparator Input. A voltage greater
than 0.85V will enable the IC. Tie this pin to VIN to enable
the IC or connect to an external resistor divider from VIN
to provide an accurate undervoltage lockout threshold.
60mV of hysteresis is provided internally.
FB (Pin 8): Feedback Input to Error Amplifier. The resis-
tor divider connected to this pin sets the buck converter
output voltage.
NC (Pin 9): No Connect Pin Must be Tied to GND.
MODE (Pin 10): Logic-Controlled Input to Select Mode
of Operation. Forcing this pin high commands high ef-
ficiency automatic Burst Mode operation where the buck
will automatically transition from PWM operation at heavy
load to Burst Mode operation at light loads. Forcing this
pin low commands low noise, fixed frequency, forced
continuous operation.
GND (Exposed Pad Pin 11): Backpad Ground Common.
This pad must be soldered to the PC board and connected
to the ground plane for optimal thermal performance.
LTC3103
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For more information www.linear.com/LTC3103
BLOCK DIAGRAM
–
+
–
+
+
–
+
UVLO
IPEAK
IPEAK(REF)
TOP_ON
BOT_ON
VREF_GOOD
SHUTDOWN CONTROL
LOGIC
ANTICROSS
CONDUCT
BURST ENABLE
TSD
VREF
UVLO
VCC
OSC
IBIAS
BOOSTVCC
VCC
PRE-REG
+
0.8V
RUN
R6
R5
0.6V 0.8V
–
+
SD LOGIC
7
BST
VIN
CBST
V
OUT
L1
VCC
6
MODE
THERMAL
SHUTDOWN
PWM
COMP
SLEEP
COMP SLEEP
REF
GND
0.6V – 10%
PWM
–
+
IPEAK
COMP
–
+
–
+
IZERO
COMP
SLOPE COMP
0.6V
SSgm
C3
10
NC
9
4
3
1
SW 2
FB R2
R1
3103 BD
8
PGOOD 5
C2
C1
LTC3103
9
3103fa
For more information www.linear.com/LTC3103
OPERATION
The LTC3103 step-down DC/DC converter is capable of
supplying 300mA to the load. The output voltage is adjust-
able over a broad range and can be set as low as 0.6V.
Both the power and the synchronous rectifier switches
are internal N-channel MOSFETs. The converter uses a
constant-frequency, current mode architecture and may
be configured using automatic Burst Mode operation for
highly efficient light load operation or configured for low
noise forced conduction continuous operation where the
converter is optimized to operate over a broad range of
step-down ratios without pulse skipping. With the auto-
matic Burst Mode feature enabled the typical DC supply
current drops to only 1.8µA with no load.
Main Control Loop
During normal operation, the internal top power MOSFET
is turned on at the beginning of each cycle and turned off
when the PWM current comparator trips. The peak induc-
tor current at which the comparator trips is controlled by
the voltage on the output of the error amplifier. The FB
pin allows the internally compensated error amplifier to
receive an output feedback voltage from an external resis-
tive divider from VOUT
. When the load current increases,
the output begins to fall causing a slight decrease in the
feedback voltage relative to the 0.6V reference, this in turn
causes the control voltage to increase until the average
inductor current matches the new load current. While the
top MOSFET is off, the bottom MOSFET is turned on until
either the inductor current starts to reverse as indicated by
the current reversal comparator, IZERO, or the beginning
of the next clock cycle. IZERO is set to 40mA (typical) in
automatic Burst Mode operation and –110mA (typical) in
forced continuous mode.
Forced Continuous Mode
Grounding MODE enables forced continuous operation
and disables Burst Mode operation. At light loads, forced
continuous mode minimizes output voltage ripple and
noise but is less efficient than Burst Mode operation.
Forced continuous operation may be desirable for use in
applications that are sensitive to the Burst Mode output
voltage ripple or its harmonics. The LTC3103 offers a broad
range of possible step-down ratios without pulse skipping
but for very small step-down ratios, the minimum on-time
of the main switch will be reached and the converter will
begin turning off for multiple cycles in order to maintain
regulation.
Burst Mode Operation
Holding the MODE pin above 1.2V will enable automatic
Burst Mode operation and disable forced continuous
operation. As the load transitions current increases the
converter will automatically transition between Burst
Mode and PWM operation. Conversely the converter will
automatically transition from PWM operation to Burst
Mode operation as the load decreases. Between bursts
the converter is not active (i.e., both switches are off)
and most of the internal circuitry is disabled to reduce the
quiescent current to 1.8µA. Burst Mode entry and exit is
determined by the peak inductor current and therefore the
load current at which Burst Mode operation will be entered
or exited depends on the input voltage, the output voltage
and the inductor value. Typical curves for Burst Mode
entry threshold are provided in the Typical Performance
Characteristics section of this data sheet.
Soft-Start
The converter has an internal closed-loop soft-start circuit
with a nominal duration of 1.4ms. The converter remains
in regulation during soft-start and will therefore respond
to output load transients that occur during this time. In
addition, the output voltage rise time has minimal depen-
dency on the size of the output capacitor or load current.
Thermal Shutdown
If the die temperature exceeds 150°C (typical) the converter
will be disabled. All power devices will be turned off and
the switch node will be forced into a high impedance state.
The soft-start circuit is reset during thermal shutdown
to provide a smooth recovery once the overtemperature
condition is eliminated. If enabled, the converter will restart
when the die temperature drops to approximately 130°C.
LTC3103
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OPERATION
Power Good Status Output
The PGOOD pin is an open-drain output which indicates
the output voltage status of the step-down converter. If the
output voltage falls 10% below the regulation voltage, the
PGOOD open-drain output will pull low. A built-in deglitch-
ing delay prevents false trips due to voltage transients on
load steps. The output voltage must rise 2% above the
falling threshold before the pull-down will turn off. The
PGOOD output will also pull low during overtemperature
shutdown and undervoltage lockout to indicate these fault
conditions. The PGOOD output is valid 1ms after the buck
converter is enabled. When the converter is disabled the
open-drain device is forced on into a low impedance state.
The PGOOD pull-up voltage must be below the 6V absolute
maximum voltage rating of the pin.
Current Limit
The peak inductor current limit comparator shuts off the
buck switch once the internal limit threshold is reached.
Peak switch current is no less than 400mA.
Slope Compensation
Current mode control requires the use of slope com-
pensation to prevent sub-harmonic oscillations in the
inductor current waveform at high duty cycle operation. In
some current mode ICs, current limiting is performed by
clamping the error amplifier voltage to a fixed maximum
which leads to a reduced output current capability at low
step-down ratios. Slope compensation is accomplished
on the LTC3103 internally through the addition of a com-
pensating ramp to the current sense signal. The current
limiting function is completed prior to the addition of the
compensation ramp and therefore achieves a peak inductor
current limit that is independent of duty cycle.
Short-Circuit Protection
When the output is shorted to ground, the error amplifier
will saturate high and the high side switch will turn on at
the start of each cycle and remain on until the current limit
trips. During this minimum on-time, the inductor current
will increase rapidly and will decrease very slowly during
the remainder of the period due to the very small reverse
voltage produced by a hard output short. To eliminate the
possibility of inductor current runaway in this situation, the
switching frequency is reduced to approximately 300kHz
when the voltage on FB falls below 0.3V.
BST Pin Function
The input switch driver operates from the voltage gener-
ated on the BST pin. An external capacitor between the SW
and BST pins and an internal synchronous PMOS boost
switch are used to generate a voltage that is higher than
the input voltage. When the synchronous rectifier is on
(SW is low) the internal boost switch connects one side
of the capacitor to VCC replenishing its charge. When the
synchronous rectifier is turned off the input switch is turned
on forcing SW high and the BST pin is at a potential equal
to VCC + SW relative to ground.
A comparator ensures there is sufficient voltage across
the boost capacitor to guarantee start-up after long sleep
periods or if starting up into a pre-biased output.
Undervoltage Lockout
The LTC3103 has an internal UVLO which disables the
converter if the supply voltage decreases below 2.1V
(typical), the converter will be disabled. The soft-start for
the converter will be reset during undervoltage lockout to
provide a smooth restart once the input voltage increases
above the undervoltage lockout threshold. The RUN pin
can alternatively be configured as a precise undervoltage
lockout (UVLO) on the VIN supply with a resistive divider
connected to the RUN pin.
LTC3103
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APPLICATIONS INFORMATION
The basic LTC3103 application circuit is shown as the
Typical Application on the front page of this data sheet.
The external component selection is determined by the
desired output voltage, output current, desired noise im-
munity and ripple voltage requirements for each particular
application. However, basic guidelines and considerations
for the design process are provided in this section.
Inductor Selection
The choice of inductor value influences both the efficiency
and the magnitude of the output voltage ripple. Larger
inductance values will reduce inductor current ripple
and will therefore lead to lower output voltage ripple. For
a fixed DC resistance, a larger value inductor will yield
higher efficiency by lowering the peak current to be closer
to the average. However, a larger value inductor within the
same family will generally have a greater series resistance,
thereby offsetting this efficiency advantage. Given a desired
peak-to-peak current ripple, ∆IL(A), the required inductance
can be calculated via the following expression:
L≥VOUT
1.2•∆IL
• 1– VOUT
VIN
µH
( )
A reasonable choice for ripple current is ∆IL = 120mA
which represents 40% of the maximum 300mA load
current. The DC current rating of the inductor should be
at least equal to the maximum load current plus half the
ripple current in order to prevent core saturation and loss
of efficiency during operation. To optimize efficiency the
inductor should have a low series resistance. In particularly
space restricted applications it may be advantageous to
use a much smaller value inductor at the expense of larger
ripple current. In such cases, the converter will operate
in discontinuous conduction for a wider range of output
loads and efficiency will be reduced. In addition, there is a
minimum inductor value required to maintain stability of the
current loop (given the fixed internal slope compensation).
Specifically, if the buck converter is going to be utilized at
duty cycles greater than 40%, the inductance value must
be at least LMIN as given by the following equation:
LMIN ≥ 2.5 • VOUT (µH)
Table 1 depicts the minimum required inductance for
several common output voltages using standard induc-
tor values.
Table 1. Minimum Inductance
OUTPUT VOLTAGE (V) MINIMUM INDUCTANCE (µH)
0.8 2.2
1.2 3.3
2.0 5.6
2.7 6.8
3.3 8.3
5.0 15
A large variety of low ESR, power inductors are available that
are well suited to the LTC3103 converter applications. The
trade-off generally involves PCB area, application height,
required output current and efficiency. Table 2 provides a
representative sampling of small surface mount inductors
that are well suited for use with the LTC3103. The induc-
tor specifications listed are for comparison purposes but
other values within these inductor families are generally
well suited to this application as well. Within each family
(i.e., at a fixed inductor size), the DC resistance generally
increases and the maximum current generally decreases
with increased inductance.
LTC3103
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APPLICATIONS INFORMATION
Output Capacitor Selection
A low ESR output capacitor should be utilized at the buck
output in order to minimize voltage ripple. Multilayer ce-
ramic capacitors are an excellent choice as they have low
ESR and are available in small footprints. In addition to
controlling the output ripple magnitude, the value of the
output capacitor also sets the loop crossover frequency
and therefore can impact loop stability. There is both a
minimum and maximum capacitance value required to
ensure stability of the loop. If the output capacitance is
too small, the loop crossover frequency will increase to
the point where switching delay and the high frequency
parasitic poles of the error amplifier will degrade the
phase margin. In addition, the wider bandwidth produced
by a small output capacitor will make the loop more sus-
ceptible to switching noise. At the other extreme, if the
output capacitor is too large, the crossover frequency
can decrease too far below the compensation zero and
also lead to degraded phase margin. Table 3 provides a
guideline for the range of allowable values of low ESR
output capacitors assuming a feedforward capacitor is
used. See the Output Voltage Programming section for
details on selecting a feedforward capacitor. Larger value
output capacitors can be accommodated provided they
have sufficient ESR to stabilize the loop, or by increasing
the value of the feedforward capacitor in parallel with the
upper resistor divider resistor.
In Burst Mode operation, the output capacitor stores energy
to satisfy the load current when the LTC3103 is in a low
current sleep state between the burst pulses. It can take
several cycles to respond to a large load step during a sleep
period. If large transient load currents are required then
a larger capacitor can be used at the output to minimize
output voltage droop until the part transitions from Burst
Mode operation to continuous mode operation.
Note that even X5R and X7R type ceramic capacitors have
a DC bias effect which reduces their capacitance when a
DC voltage is applied. It is not uncommon for capacitors
offered in the smallest case sizes to lose more than 50%
of their capacitance when operated near their rated volt-
age. As a result it is sometimes necessary to use a larger
capacitance value or use a higher voltage rating in order to
realize the intended capacitance value. Consult the manu-
facturer’s data for the capacitor you select to be assured
of having the necessary capacitance in your application.
Table 3. Recommended Output Capacitor Limits
OUTPUT VOLTAGE (V) CMIN (µF) CMAX (µF)
0.8 22.0 220
1.2 15.0 220
2.0 12.0 100
2.7 6.8 68
3.3 4.7 47
5.0 4.7 47
Table 2. Representative Inductor Selection
PART NUMBER
VALUE
(µH)
DCR
(Ω)
MAX DC
CURRENT
(A)
SIZE (MM)
W × L × H
Coilcraft
EPL3015 6.8 0.19 1.00 3.0 × 3.0 × 1.5
LPS3314 10 0.33 0.70 3.3 × 3.3 × 1.3
LPS4018 15 0.26 1.12 4.0 × 4.0 × 1.8
Cooper-Bussman
SD3114 6.8 0.30 0.98 3.1 × 3.1 × 1.4
SD3118 10 0.3 0.75 3.2 × 3.2 × 1.8
Murata
LQH3NPN 6.8 0.20 1.25 3.0 × 3.0 × 1.4
LQH44PN 10 0.16 1.10 4.0 × 4.0 × 1.7
Sumida
CDRH3D16 6.8 0.17 0.73 3.8 × 3.8 × 1.8
CDRH3D16 10 0.21 0.55 3.8 × 3.8 × 1.8
Taiyo-Yuden
CBC3225 6.8 0.16 0.93 3.2 × 2.5 × 2.5
NR3015 10 0.23 0.70 3.0 × 3.0 × 1.5
NR4018 15 0.30 0.65 4.0 × 4.0 × 1.8
Würth
744029006 6.8 0.25 0.95 2.8 × 2.8 × 1.4
744031006 6.8 0.16 0.85 3.8 × 3.8 × 1.7
744031100 10 0.19 0.74 3.8 × 3.8 × 1.7
744031100 15 0.26 0.62 3.8 × 3.8 × 1.7
Panasonic
ELLVGG6R8N 6.8 0.23 1.00 3.0 × 3.0 × 1.5
ELL4LG100MA 10 0.20 0.80 3.8 × 3.8 × 1.8
TDK
VLF3012 6.8 0.18 0.78 3.0 × 2.8 × 1.2
VLC4018 10 0.16 0.85 4.0 × 4.0 × 1.8
LTC3103
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Input Capacitor Selection
The VIN pin provides current to the power stages of the
buck converter. It is recommended that a low ESR ceramic
capacitor with a value of at least 10µF be used to bypass
the pin. These capacitors should be placed as close to
the pin as possible and should have a short return path
to the GND pin.
Output Voltage Programming
The output voltage is set by a resistive divider according
to the following formula:
VOUT =0.6V • 1+
R2
R1
The external divider is connected to the output as shown
in Figure 1. Note that FB divider current is not included in
the LTC3103 quiescent current specification. For improved
transient response, a feedforward capacitor, CFF
, may be
placed in parallel with resistor R2. The capacitor modifies
the loop dynamics by adding a pole-zero pair to the loop
dynamics which generates a phase boost that can improve
the phase margin and increase the speed of the transient
response, resulting in smaller voltage deviation on load
transients. The zero frequency depends not only on the
value of the feed forward capacitor, but also on the upper
resistor divider resistor. Specifically, the zero frequency,
fZERO, is given by the following equation:
fZERO =
1
2•π•R2•C
FF
For R2 resistor values of ~1M a 12pF ceramic capacitor
will suffice, however that value may be increased or de-
creased to optimize the converter’s response for a given
set of application parameters. In a Burst Mode application
for instance, a CFF = 27pF will lower output voltage ripple
at light load.
Minimum Off-Time/On-Time Considerations
The maximum duty cycle is limited in the LTC3103 by the
boost capacitor refresh time, the rise/fall times of the switch
as well as propagation delays in the PWM comparator, the
level shifts and the gate drive. This minimum off time is
typically 65ns which imposes a maximum duty cycle of:
DCMAX = 1 – (f • tOFF(MIN))
where f is the 1.2MHz switching frequency and tOFF(MIN)
is the minimum off-time. If the maximum duty cycle is
surpassed, due to a dropping input voltage for example,
the output will drop out of regulation. The minimum input
voltage to avoid this dropout condition is:
VIN(MIN) =
V
OUT
1– f • tOFF(MIN)
( )
Conversely, the minimum on-time is the smallest duration
of time in which the buck switch can be in its “on” state.
This time is limited by similar factors and is typically 70ns.
In forced continuous operation, the minimum on-time limit
imposes a minimum duty cycle of:
DCMIN = f • tON(MIN)
where tON(MIN) is the minimum on-time. In extreme step-
down ratios where the minimum duty cycle is surpassed,
the output voltage will still be in regulation but the rectifier
switch will remain on for more than one cycle and sub-
harmonic switching will occur to provide a higher effective
duty cycle. The result is higher output voltage ripple. This
is an acceptable result in many applications so this con-
straint may not be of critical importance in some cases.
Precise Undervoltage Lockout
The LTC3103 is in shutdown when the RUN pin is low and
active when the pin is higher than the RUN pin threshold.
The rising threshold of the RUN pin comparator is an ac-
curate 0.8V, with 60mV of hysteresis. This threshold is
enabled when VIN is above the 2.5V minimum value. If VIN
is lower than 2.5V, an internal undervoltage monitor puts
the part in shutdown independent of the RUN pin state.
The RUN pin can be configured as a precise undervoltage
lockout (UVLO) on the VIN supply with a resistive divider
FB
R2
R1
CFF
3103 F01
VOUT
GND
LTC3103
Figure 1. Setting the Output Voltage
APPLICATIONS INFORMATION
LTC3103
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tied to the RUN pin as shown in Figure 2 to meet specific
VIN voltage requirements. If used, note that the external
divider current is not included in the LTC3103 quiescent
current specification.
The rising UVLO threshold can be calculated using the
following equation:
VUVLO =0.8V • 1+
R4
R3
APPLICATIONS INFORMATION
Internal VCC Regulator
The LTC3103 uses an internal NMOS source follower
regulator off of VIN to generate a low voltage internal rail,
VCC. The regulator is designed to deliver current only to
the internal drivers and other internal control circuits and
not to an external load. The VCC pin should be bypassed
with a 1µF or larger ceramic capacitor.
Boost Capacitor Selection
The LTC3103 uses a bootstrapped supply to power the
buck switch gate drivers. When the synchronous rectifier
turns on, an internal PMOS switch turns on synchronously
to charge the boost capacitor, CBST
, to the voltage on VCC.
For most applications a 0.022µF will suffice. The capaci-
tor should be placed as close to their respective pins as
possible.
Figure 3. PCB Layout Recommendations
10
9
6
7
8
4
5
3
2
1MODE
NC
FB
RUN
VCC
VIN
SW
BST
GND
PGOOD KELVIN TO VOUT
3103 F03
UNINTERRUPTED GROUND PLANE
SHOULD EXIST UNDER ALL COMPONENTS
SHOWN AND UNDER THE TRACES
CONNECTING THOSE COMPONENTS
VOUT
VIA GROUND PLANE
VIN
RUN
LTC3103
GND
VIN
R3
R4
3103 F02
Figure 2. Setting the Undervoltage Lockout Threshold
LTC3103
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TYPICAL APPLICATIONS
VIN CBST
0.022µF
BST
VIN
5V TO 9V
MODE SW
RUN
PGOOD
PGOOD
VCC FB
LTC3103
GND
R1
442k
L1
10µH VOUT
3.3V
300mA
1M
3103 TA02a
47µF
L1: TDK VLC4018
1µF
10µF R2
2M
CFF
22pF
Portable LF RFID Reader, Dual Lithium-Ion to 3.3V/300mA
Regulator with Ultralow IQ
Efficiency vs Output Current
12V to 2.2V/300mA Regulator with 9V Accurate UVLO Start-Up with Ramped Input Power
VIN CBST
0.022µF
BST
VIN
12V
MODE SW
RUN PGOOD
PGOOD
VCC FB
LTC3103
GND
R1
665k
R4
2.05M
R3
200k
L1
10µH VOUT
2.2V
300mA
1M
3103 TA03a
47µF
L1: MURATA LQH44PN1
1µF
10µF R2
1.78M
CFF
22pF
LOAD CURRENT (A)
80
EFFICIENCY (%)
90
100
70
85
95
0.0001 0.01 0.1 1
3103 TA02b
60
75
65
0.001
VIN = 5V
VIN = 9V
VOUT
1V/DIV
VIN
5V/DIV
IL
100mA/DIV
20ms/DIV 3103 TA03b
LTC3103
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For more information www.linear.com/LTC3103
TYPICAL APPLICATIONS
Solar-Powered 2.2V Supply with Li Battery Backup and Run Threshold Set to Battery Minimum Voltage
5V to 1.2V/300mA Low Noise Regulator Using Forced Continuous Operation
Efficiency vs Output Current
VIN CBST
0.022µF
BST
VIN
5V
MODE SW
RUN PGOOD
PGOOD
VCC FB
LTC3103
GND
R1
402k
L1
4.7µH VOUT
1.2V
300mA
1M
3103 TA05a
10µF
L1: SUMIDA CDRH4D11NP-4R7N
1µF
10µF
ON
OFF
R2
402k
CFF
22pF
OUTPUT CURRENT (A)
30
EFFICIENCY (%)
90
100
20
10
80
50
70
60
40
0.0001 0.01 0.1
1
3103 TA05b
0
0.001
VIN = 2.5V
VIN = 3.3V
VIN = 5V
VIN
CBST
22nF
BST
MODE
SW
RUN
PGOOD
VCC FB
LTC3103
GND
R1
665k
R4
3.09M
SDM20E-40C
R3
715k
L1
15µH V
OUT
2.2V
3103 TA04
COUT
22µF
C1
1µF
L1: COILCRAFT LP54018
CIN
10µF
CBULK
100µF
3.6V TADIRAN
AA LITHIUM
BATTERY
R2
1.78M
CFF
22pF
3.2V RUN
THRESHOLD
+
4.8V, 0.5W
SOLAR PANEL
MPT4.8-150
(6.5VOC)
+
+
LTC3103
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DD Package
10-Lead Plastic DFN (3mm × 3mm)
(Reference LTC DWG # 05-08-1699 Rev C)
3.00 ±0.10
(4 SIDES)
NOTE:
1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-2).
CHECK THE LTC WEBSITE DATA SHEET FOR CURRENT STATUS OF VARIATION ASSIGNMENT
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE
TOP AND BOTTOM OF PACKAGE
0.40 ± 0.10
BOTTOM VIEW—EXPOSED PAD
1.65 ± 0.10
(2 SIDES)
0.75 ±0.05
R = 0.125
TYP
2.38 ±0.10
(2 SIDES)
15
106
PIN 1
TOP MARK
(SEE NOTE 6)
0.200 REF
0.00 – 0.05
(DD) DFN REV C 0310
0.25 ± 0.05
2.38 ±0.05
(2 SIDES)
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
1.65 ±0.05
(2 SIDES)2.15 ±0.05
0.50
BSC
0.70 ±0.05
3.55 ±0.05
PACKAGE
OUTLINE
0.25 ± 0.05
0.50 BSC
PIN 1 NOTCH
R = 0.20 OR
0.35 × 45°
CHAMFER
PACKAGE DESCRIPTION
Please refer to http://www.linear.com/product/LTC3103#packaging for the most recent package drawings.
LTC3103
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MSOP (MSE) 0213 REV I
0.53 ±0.152
(.021 ±.006)
SEATING
PLANE
0.18
(.007)
1.10
(.043)
MAX
0.17 –0.27
(.007 – .011)
TYP
0.86
(.034)
REF
0.50
(.0197)
BSC
1234 5
4.90 ±0.152
(.193 ±.006)
0.497 ±0.076
(.0196 ±.003)
REF
8910
10
1
76
3.00 ±0.102
(.118 ±.004)
(NOTE 3)
3.00 ±0.102
(.118 ±.004)
(NOTE 4)
NOTE:
1. DIMENSIONS IN MILLIMETER/(INCH)
2. DRAWING NOT TO SCALE
3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.
MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX
6. EXPOSED PAD DIMENSION DOES INCLUDE MOLD FLASH. MOLD FLASH ON E-PAD
SHALL NOT EXCEED 0.254mm (.010") PER SIDE.
0.254
(.010) 0° – 6° TYP
DETAIL “A”
DETAIL “A”
GAUGE PLANE
5.10
(.201)
MIN
3.20 – 3.45
(.126 – .136)
0.889 ±0.127
(.035 ±.005)
RECOMMENDED SOLDER PAD LAYOUT
1.68 ±0.102
(.066 ±.004)
1.88 ±0.102
(.074 ±.004)
0.50
(.0197)
BSC
0.305 ± 0.038
(.0120
±.0015)
TYP
BOTTOM VIEW OF
EXPOSED PAD OPTION
1.68
(.066)
1.88
(.074)
0.1016 ±0.0508
(.004 ±.002)
DETAIL “B”
DETAIL “B”
CORNER TAIL IS PART OF
THE LEADFRAME FEATURE.
FOR REFERENCE ONLY
NO MEASUREMENT PURPOSE
0.05 REF
0.29
REF
MSE Package
10-Lead Plastic MSOP, Exposed Die Pad
(Reference LTC DWG # 05-08-1664 Rev I)
PACKAGE DESCRIPTION
Please refer to http://www.linear.com/product/LTC3103#packaging for the most recent package drawings.
LTC3103
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For more information www.linear.com/LTC3103
REVISION HISTORY
REV DATE DESCRIPTION PAGE NUMBER
A 07/16 Updated Typical Application circuit.
Updated Input Voltage Range condition to include After Start-Up. Added another line for Start-Up.
Updated Soft-Start Time condition to include VIN = 5V.
Corrected G04 to remove LDO ENABLED
Replaced G13.
Corrected RUN Pin Function description.
Replaced Block Diagram, VCC regulator pass element PMOS with NMOS.
Updated Application Information.
Updated both application circuits.
Updated applications title.
Updated application circuit.
1
2
3
4
5
7
8
13
15
16
20
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
LTC3103
20
3103fa
LINEAR TECHNOLOGY CORPORATION 2011
LT 0716 REV A • PRINTED IN USA
For more information www.linear.com/LTC3103
RELATED PARTS
TYPICAL APPLICATION
12V to 5V/300mA Regulator with High Efficiency, Ultralow IQ
(1.8µA with VOUT in Regulation, No Load)
VIN CBST
0.022µF
BST
VIN
12V
MODE SW
RUN PGOOD
VCC FB
LTC3103
GND
R1
255k
L1
10µH VOUT
5V
300mA
1M
PGOOD
3103 TA06
47µF
L1: SUMIDA CDRH4D16FB
1µF
10µF R2
1.87M
CFF
27pF
PART NUMBER DESCRIPTION COMMENTS
LTC3104 15V, 300mA Synchronous Step-Down DC/DC Converter
with Ultralow Quiescent Current and 10mA LDO
VIN: 2.5V to 15V, VOUT(MIN) = 0.6V, IQ = 2.8µA, ISD = 1µA,
3mm × 3mm DFN-10, MSOP-10
LTC3642 45V (Transient to 60V) 50mA Synchronous Step-Down
DC/DC Converter
VIN: 4.5V to 45V, VOUT(MIN) = 0.8V, IQ = 12µA, ISD < 1µA,
3mm × 3mm DFN-8, MSOP-8
LTC3631 45V (Transient to 60V) 100mA Synchronous Step-Down
DC/DC Converter
VIN: 4.5V to 45V, VOUT(MIN) = 0.8V, IQ = 12µA, ISD < 1µA,
3mm × 3mm DFN-8, MSOP-8
LTC3632 50V (Transient to 60V) 20mA Synchronous Step-Down
DC/DC Converter
VIN: 4.5V to 50V, VOUT(MIN) = 0.8V, IQ = 12µA, ISD < 1µA,
3mm × 3mm DFN-8, MSOP-8
LTC3388-1/LTC3388-3 20V, 50mA High Efficiency Nano Power Step-Down
Regulators
VIN: 2.7V to 20V, VOUT(MIN) Fixed 1.1V to 5.5V, IQ = 720nA,
ISD = 400nA, 3mm × 3mm DFN-10, MSOP-10
LTC3108/LTC3108-1 Ultralow Voltage Step-Up Converter and Power Managers VIN: 0.02V to 1V, VOUT(MIN) Fixed 2.35V to 5V, IQ = 6µA,
ISD < 1µA, 3mm × 4mm DFN-12, SSOP-16
LTC3109 Auto-Polarity, Ultralow Voltage Step-Up Converter
and Power Manager
VIN: 0.03V to 1V, VOUT(MIN) Fixed 2.35V to 5V, IQ = 7µA,
ISD < 1µA, 4mm × 4mm QFN-20, SSOP-20
LTC4071 Li-Ion/Polymer Shunt Battery Charger System with Low
Battery Disconnect
Charger Plus Pack Protection in One IC Low Operating Current
(550nA), 50mA Internal Shunt Current, Pin Selectable Float
Voltages (4.0V, 4.1V, 4.2V), 8-Lead, 2mm × 3mm, DFN and MSOP
Packages
LTC4070 Li-Ion/Polymer Low Current Shunt Battery Charger System Selectable VFLOAT = 4.0V, 4.1V, 4.2V, Max Shunt Current = 50mA,
ICCQ = 450nA to 1.04mA, ICCQLB = 300nA, 2mm × 3mm DFN-8,
MSOP-8
LTC1877 10V, 600mA High Efficiency Synchronous Step-Down
DC/DC Converter
VIN: 2.65V to 10V, VOUT(MIN) = 0.8V, IQ = 10µA, ISD < 1µA, MSOP-8
LTC3105 5V, 400mA, MPPC Step-Up Converter with 250mV Start-Up VIN: 0.225V to 5V, VOUT(MAX) = 5.25V, IQ = 24µA, ISD = 10µA,
3mm × 3mm DFN-10, MSOP-12
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com/LTC3103