LTC3103 - 1.8μA Quiescent Current, 15V, 300mA Synchronous Step-Down DC/DC Converter

LTC3103
1.8µA Quiescent Current,
15V, 300mA Synchronous
Step-Down DC/DC
Converter
DESCRIPTION
FEATURES
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Ultralow Quiescent Current: 1.8µA
Synchronous Rectification: Efficiency Up to 95%
Wide VIN Range: 2.5V to 15V
Wide VOUT 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 VOUT
Available in Thermally Enhanced 3mm × 3mm ×
0.75mm, 10-Pin DFN and 10-Pin MSOP Packages
APPLICATIONS
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Remote Sensor Networks
Distributed Power Systems
Multicell Battery or SuperCap Regulator
Energy Harvesters
Portable Instruments
Low Power Wireless Systems
The LTC®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 allowing 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 comparator, 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.
TYPICAL APPLICATION
Efficiency vs Output Current
100
BST
MODE
0.022µF
10µH
SW
10µF
RUN PGOOD
FB
VCC
GND
1.78M
12pF
47µF
1µF
665k
90
85
75
70
1
65
60
3103 TA01a
10
80
55
50
0.0001
VIN = 3V
VIN = 5V
VIN = 10V
VIN = 15V
0.01
0.1
0.001
OUTPUT CURRENT (A)
1
POWER LOSS (mW)
LTC3103
100
95
2.2V
300mA
EFFICIENCY (%)
VIN
3V TO 15V
0.1
3103 TA01b
3103f
1
LTC3103
ABSOLUTE MAXIMUM RATINGS
(Note 1)
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
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
VIN
1
SW
2
BST
3
GND
4
PGOOD
5
TOP VIEW
10 MODE
11
GND
VIN
SW
BST
GND
PGOOD
9 NC
8 FB
7 RUN
6 VCC
DD PACKAGE
10-LEAD (3mm × 3mm) PLASTIC DFN
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
10
9
8
7
6
11
GND
MODE
NC
FB
RUN
VCC
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
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.
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/
The
l denotes the specifications which apply over the full operating
ELECTRICAL
CHARACTERISTICS
junction temperature range, otherwise specifications are at TA = 25°C (Note 2). VIN = 10V unless otherwise noted.
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Step-Down Converter
Input Voltage Range
l
Input Undervoltage Lockout Threshold
VIN Rising
VIN Rising, TJ = 0°C to 85°C (Note 4)
Input Undervoltage Lockout Hysteresis
(Note 4)
l
2.5
2.1
2.1
0.4
15
V
2.6
2.5
V
V
V
3103f
2
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.
PARAMETER
CONDITIONS
Feedback Voltage
(Note 5)
Feedback Voltage Line Regulation
VIN = 2.5V to 15V (Note 5)
Feedback Input Current
(Note 5)
Oscillator Frequency
MIN
l
0.588
l
l
TJ = 0°C to 85°C (Note 4)
0.930
1
TYP
MAX
0.6
0.612
V
0.02
0.05
%/V
1
20
1.2
1.2
1.55
1.45
UNITS
nA
MHz
MHz
Quiescent Current, VIN—Active
RUN = VIN, MODE = 0V, FB > 0.612 Nonswitching
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
RUN = 0V, TJ = 0°C to 85°C (Note 4)
RUN = 0V
l
1
1.8
1.7
3.3
µA
µA
Quiescent Current, VIN—Shutdown
600
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
N-Channel MOSFET Switch RDS(ON)
ISW = –200mA
Peak Current Limit
0.65
l
Ω
0.40
0.50
0.75
A
–14
–10
–5
%
PGOOD Threshold
FB Falling, Percentage Below FB
PGOOD Hysteresis
Percentage of FB
PGOOD Voltage Low
IPGOOD = 100µA
0.2
PGOOD Leakage Current
VPGOOD = 5V
0.01
Maximum Duty Cycle
Ω
2
V
0.3
µA
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
l
l
89
%
0.76
RUN Pin Hysteresis
RUN Input Current
0.85
0.06
RUN = 1.2V
MODE Threshold
MODE Input Current
0.80
l
l
0.5
MODE = 1.2V
Soft-Start Time
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)
0.7
V
V
0.01
0.4
µA
0.8
1.2
V
0.1
4
µA
1.4
2.5
ms
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.
3103f
3
LTC3103
TYPICAL PERFORMANCE CHARACTERISTICS
Efficiency vs Output Current
100
90
85
85
80
75
70
65
VIN = 4V
VIN = 7V
VIN = 10V
VIN = 15V
0.01
0.1
0.001
OUTPUT CURRENT (A)
75
70
65
ILOAD = 300mA
ILOAD = 100mA
ILOAD = 10mA
ILOAD = 1mA
ILOAD = 100µA
60
55
50
1
12
10
8
INPUT VOLTAGE (V)
4
2
6
14
3103 G01
100
80
80
70
70
60
50
40
0
0.0001
VIN = 3.7V
VIN = 5V
VIN = 7V
VIN = 10V
VIN = 15V
0.001
0.01
0.1
OUTPUT CURRENT (A)
50
40
30
10
8
FREQUENCY CHANGE (%)
CHANGE IN VFB (%)
1.5
1.0
0.5
3
5
9
7
11
INPUT VOLTAGE (V)
13
0
15
50
NORMALIZED TO 25°C
40
6
4
2
0
–2
–4
–6
2
4
10
8
12
6
INPUT VOLTAGE (V)
–10
–50 –25
14
16
RDS(ON) vs Temperature
NORMALIZED TO 25°C
VIN = 10V
30
20
SYNCHRONOUS
RECTIFIER
10
MAIN
SWITCH
0
–10
–20
–8
3103 G07
FRONT PAGE APPLICATION
LDO ENABLED
3103 G06
CHANGE IN RESISTANCE (%)
NORMALIZED TO 25°C
18
2.0
Oscillator Frequency
vs Temperature
–0.50
– 60 – 40 – 20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
16
2.5
3103 G05
Feedback Voltage
vs Temperature
–0.25
6
8 10 12 14
INPUT VOLTAGE (V)
3.0
60
0
1
0
4
3.5
10
0.25
2
3103 G03
20
0.50
0
Application No-Load Input Current
vs Supply Voltage (Forced
Continuous Operation)
ILOAD = 300mA
ILOAD = 100mA
ILOAD = 10mA
ILOAD = 1mA
3103 G04
0.75
1.6
16
VOUT = 3.3V, L = 10µH
90
EFFICIENCY (%)
EFFICIENCY (%)
VOUT = 3.3V
90 L = 10µH
10
1.8
Efficiency vs Input Voltage
(Forced Continuous Operation)
100
20
1.9
3103 G02
Efficiency vs Output Current
(Forced Continuous Operation)
30
2.0
1.7
INPUT CURRENT (mA)
50
0.0001
80
FRONT PAGE APPLICATION
2.1
INPUT CURRENT (µA)
90
2.2
VOUT = 2.2V
L = 10µH
95
EFFICIENCY (%)
EFFICIENCY (%)
VOUT = 3.3V
95 L = 15µH
55
Application No-Load Input Current
vs Supply Voltage (Automatic
Burst Mode Operation)
Efficiency vs Input Voltage
(Automatic Burst Mode Operation)
100
60
TA = 25°C unless otherwise noted
0
25 50 75 100 125 150
TEMPERATURE (°C)
3103 G08
–30
–50 –25
75
50
25
TEMPERATURE (°C)
0
100
125
3103 G09
3103f
4
LTC3103
TYPICAL PERFORMANCE CHARACTERISTICS
PEAK CURRENT LIMIT CHANGE (%)
LEAKAGE CURRENT (nA)
350
SYNCHRONOUS
RECTIFIER
250
MAIN
SWITCH
200
150
100
50
0
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
10.0
3.0
7.5
2.8
2.5
0
–2.5
–5.0
–20
10
70
40
TEMPERATURE (°C)
RUN
5V/DIV
VOUT
1V/DIV
PGOOD
5V/DIV
IL
100mA/DIV
100
130
Forced Continuous Operation
3103 G13
Start-Up into Pre-Biased Output
(Forced Continuous Operation)
VBST REFRESH
CURRENT PULSES
ILOAD = 2mA
VIN = 10V
L = 10µH
VOUT = 2.5V
500µs/DIV
1.6
1.0
–50 –30 –10 10 30 50 70
TEMPERATURE (°C)
Start-Up into Pre-Biased Output
(Automatic Burst Mode Operation)
VBST REFRESH
CURRENT PULSES
SOFT-START
PERIOD
BURST CURRENT
PULSES
IL
100mA/DIV
ILOAD = 25mA
VIN = 10V
CIN = 10µF
L = 10µH
VOUT = 2.5V
COUT = 22µF
RUN
5V/DIV
PGOOD
5V/DIV
VOUT
1V/DIV
110
90
3103 G12
PGOOD
5V/DIV
1µs/DIV
3103 G14
ILOAD = 2mA
VIN = 10V
CIN = 10µF
L = 10µH
VOUT = 2.5V
COUT = 47µF
500µs/DIV
3103 G15
Start-Up from Shutdown
(Forced Continuous Operation)
Start-Up from Shutdown
(Automatic Burst Mode Operation)
RUN
5V/DIV
VOUT
1V/DIV
SOFT-START
FOLDBACK PERIOD
IL
100mA/DIV
IL
100mA/DIV
3103 G16
1.8
RUN
5V/DIV
VOUT
1V/DIV
IL
100mA/DIV
10µs/DIV
2.0
3103 G11
VOUT
20mV/DIV
AC-COUPLED
ILOAD = 25mA
VIN = 10V
CIN = 10µF
L = 10µH
VOUT = 2.5V
COUT = 22µF
2.2
1.2
–10.0
–50
Automatic Burst Mode Operation
IL
100mA/DIV
2.4
1.4
–7.5
3103 G10
VOUT
50mV/DIV
AC-COUPLED
VIN = 10V
VOUT = 2.5V
2.6
5.0
INPUT CURRENT (µA)
VIN = 10V
300
Application No-Load Input Current
vs Temperature (Automatic Burst
Mode Operation)
Peak Current Limit Change
vs Temperature
SW Leakage vs Temperature
400
TA = 25°C unless otherwise noted
ILOAD = 25mA
VIN = 10V
L = 10µH
VOUT = 2.5V
500µs/DIV
3103 G17
ILOAD = 5mA
VIN = 10V
L = 10µH
VOUT = 2.5V
500µs/DIV
3103 G18
3103f
5
LTC3103
TYPICAL PERFORMANCE CHARACTERISTICS
VOUT
200mV/DIV
AC-COUPLED
VOUT
50mV/DIV
AC-COUPLED
IL
200mA/DIV
IL
100mA/DIV
3103 G19
200µs/DIV
ILOAD = LOAD STEP, 5mA TO 300mA
VIN = 10V
CIN = 10µF
L = 10µH
VOUT = 2.2V
COUT = 47µF
VOUT = 9V
9
150
200
100
LOAD CURRENT (mA)
250
–2.0
300
–1.0
COUT = 68µF
COUT = 47µF
COUT = 22µF
0
10
20
30
ILOAD (mA)
50
40
–1.0
–1.5
–2.0
COUT = 100µF
COUT = 68µF
COUT = 47µF
–2.5
0
20
40
60
ILOAD (mA)
80
100
3103 G25
COUT = 68µF
COUT = 47µF
COUT = 33µF
–1.5
–2.0
0
10
20
30 40 50
ILOAD (mA)
60
Automatic Burst Mode Threshold
vs Supply Voltage
100
160
95
140
IOUT = 1mA
90
IOUT = 300mA
85
80
75
70
65
2
3
6
5
7
4
INPUT VOLTAGE (V)
80
70
3103 G24
BURST THRESHOLD (ILOAD, mA)
CHANGE IN VOUT (%)
–0.5
NORMALIZED AT ILOAD = 100mA
VIN = 10V
VOUT = 3.3V
CFF = 12pF
0
Maximum Duty Cycle
vs Input Voltage
MAXIMUM DUTY CYCLE (%)
NORMALIZED AT ILOAD = 100mA
VIN = 10V
VOUT = 1.8V
CFF = 12pF
0
300
Load Regulation
(Automatic Burst Mode Operation)
3103 G23
Load Regulation
(Automatic Burst Mode Operation)
0.5
250
–0.5
3103 G22
1.0
100
150
200
LOAD CURRENT (mA)
50
0.5
0
–1.5
VOUT = 5V
50
0
1.0
–1.0
8
–3.0
2.5
–0.5
10
0
3.5
CHANGE IN VOUT (%)
CHANGE IN VOUT (%)
12
6
VOUT = 2.2V
VOUT = 1.8V
VOUT = 1.5V
3.0
NORMALIZED AT ILOAD = 100mA
VIN = 10V
VOUT = 5V
CFF = 12pF
0.5
13
7
4.0
Load Regulation
(Automatic Burst Mode Operation)
VOUT = 12V
11
3103 G20
VOUT = 4.2V
VOUT = 3.3V
VOUT = 2.5V
4.5
3103 G21
1.0
15
14
INPUT VOLTAGE (V)
5.0
200µs/DIV
ILOAD = LOAD STEP, 50mA TO 200mA
VIN = 10V
L = 10µH
VOUT = 2.5V
COUT = 22µF
Minimum Input Voltage at
Maximum Duty Cycle vs Load
Current
5
5.5
ILOAD
100mA/DIV
ILOAD
200mA/DIV
Minimum Input Voltage at
Maximum Duty Cycle vs Load
Current
Load Step
(Forced Continuous Operation)
INPUT VOLTAGE (V)
Load Step
(Automatic Burst Mode Operation)
TA = 25°C unless otherwise noted
8
9
3103 G26
VOUT = 1.2V
VOUT = 1.8V
VOUT = 2.5V
VOUT = 3.3V
VOUT = 5V
120
100
80
60
40
20
0
0
2
4
8
6
10 12
INPUT VOLTAGE (V)
14
16
3103 G27
3103f
6
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 0.84V 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 resistor 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 efficiency 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.
3103f
7
LTC3103
BLOCK DIAGRAM
C2
1
VIN
VCC
6
VCC
PRE-REG
VCC
C3
VCC
IBIAS
UVLO
OSC
IPEAK(REF)
IPEAK
0.6V 0.8V
+
UVLO
R6
7
RUN
VREF
+
R5
0.8V
10
MODE
BURST ENABLE
BST
3
CBST
IPEAK
COMP
TOP_ON
VREF_GOOD
SHUTDOWN
SD LOGIC
–
BOOST
CONTROL
LOGIC
BOT_ON
SW
ANTICROSS
CONDUCT
–
+
TSD
–
THERMAL
SHUTDOWN
9 NC
PWM
PWM
COMP
IZERO
COMP
SLOPE COMP
–
gm
+
–
VOUT
C1
+
+
SLEEP
COMP
L1
2
+
+
–
0.6V
SS
FB
R2
8
R1
SLEEP
REF
–
0.6V – 10%
PGOOD
5
+
GND
4
3103 BD
3103f
8
LTC3103
OPERATION
The LTC3103 step-down DC/DC converter is capable of
supplying 300mA to the load. The output voltage is adjustable 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 automatic 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 inductor 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 resistive 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 dependency 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.
3103f
9
LTC3103
OPERATION
Power Good Status Output
Short-Circuit Protection
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 deglitching 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.
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.
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 compensation 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 compensating 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.
BST Pin Function
The input switch driver operates from the voltage generated 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.
3103f
10
LTC3103
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 immunity and ripple voltage requirements for each particular
application. However, basic guidelines and considerations
for the design process are provided in this section.
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:
Inductor Selection
LMIN ≥ 2.5 • VOUT (µH)
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
 V 
•  1– OUT  (µH)
VIN 

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
Table 1 depicts the minimum required inductance for
several common output voltages using standard inductor 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 inductor 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.
3103f
11
LTC3103
APPLICATIONS INFORMATION
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
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
Cooper-Bussman
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
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
Sumida
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
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
Würth
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
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
TDK
Output Capacitor Selection
A low ESR output capacitor should be utilized at the buck
output in order to minimize voltage ripple. Multilayer ceramic 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 susceptible 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 voltage. 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 manufacturer’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
3103f
12
LTC3103
APPLICATIONS INFORMATION
Input Capacitor Selection
Minimum Off-Time/On-Time Considerations
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.
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:
Output Voltage Programming
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:
The output voltage is set by a resistive divider according
to the following formula:
 R2 
VOUT = 0.6V •  1+ 
 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 • CFF1
For R2 resistor values of ~1M a 12pF ceramic capacitor
will suffice, however that value may be increased or decreased to optimize the converter’s response for a given
set of application parameters.
VOUT
R2
CFF
FB
LTC3103
R1
GND
3103 F01
Figure 1. Setting the Output Voltage
DCMAX = 1 – (f • tOFF(MIN))
VIN(MIN) =
(
VOUT
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 stepdown 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 subharmonic 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 constraint
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
accurate 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
3103f
13
LTC3103
APPLICATIONS INFORMATION
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:
 R4 
VUVLO = 0.8V •  1+ 
 R3 
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 capacitor should be placed as close to their respective pins as
possible.
VIN
R4
RUN
R3
LTC3103
GND
3103 F02
Figure 2. Setting the Undervoltage Lockout Threshold
VIN
VOUT
VIA GROUND PLANE
VIN
1
10 MODE
SW
2
9 NC
BST
3
8 FB
GND
4
7 RUN
PGOOD
5
6 VCC
KELVIN TO VOUT
UNINTERRUPTED GROUND PLANE
SHOULD EXIST UNDER ALL COMPONENTS
SHOWN AND UNDER THE TRACES
CONNECTING THOSE COMPONENTS
3103 F03
Figure 3. PCB Layout Recommendations
3103f
14
LTC3103
TYPICAL APPLICATIONS
Portable LF RFID Reader, Dual Lithium-Ion to 3.3V/300mA
Regulator with Ultralow IQ
VIN
BST
MODE
SW
95
CBST
0.022µF
LTC3103
PGOOD
RUN PGOOD
L1
10µH
1M
VOUT
3.3V
300mA
R2
2M
10µF
VCC
100
FB
90
EFFICIENCY (%)
VIN
5V TO 9V
Efficiency vs Output Current
CFF
12pF
GND
1µF
VIN = 5V
85
VIN = 9V
80
75
70
65
47µF
R1
442k
60
0.0001
3103 TA02a
L1: TDK VLC4018
0.001
0.01
0.1
LOAD CURRENT (A)
1
3103 TA02b
12V to 2.2V/300mA Regulator with 9V Accurate UVLO
VIN
12V
VIN
R4
2.05M
10µF
R3
200k
BST
MODE
SW
LTC3103
RUN PGOOD
VCC
FB
GND
1µF
CBST
0.022µF
L1
10µH
PGOOD
1M
VOUT
2.2V
300mA
R2
1.78M
VIN
5V/DIV
VOUT
1V/DIV
IL
100mA/DIV
CFF
12pF
R1
665k
Start-Up with Ramped Input Power
47µF
20ms/DIV
3103 TA03b
3103 TA03a
L1: MURATA LQH44PN1
3103f
15
LTC3103
TYPICAL APPLICATIONS
Slolar-Powered 2.2V Supply with Li Battery Backup and Run Threshold Set to Battery Minimum Voltage
SDM20E-40C
R4
3.09M
+
+
3.6V TADIRAN
AA LITHIUM
BATTERY
4.8V, 0.5W
SOLAR PANEL
MPT4.8-150
(6.5VOC)
+
CBULK
100µF
BST
VIN
3.2V RUN
THRESHOLD
SW
RUN
R3
715k
CIN
10µF
CBST
22nF
LTC3103
MODE PGOOD
FB
VCC
GND
C1
1µF
L1
15µH
VOUT
2.2V
R2
1.78M
CFF
22pF
R1
665k
COUT
22µF
3103 TA04
L1: COILCRAFT LP54018
3103f
16
LTC3103
TYPICAL APPLICATIONS
5V to 1.2V/300mA Low Noise Regulator Using Forced Continuous Operation
VIN
5V
VIN
BST
MODE
SW
LTC3103
ON
OFF
RUN PGOOD
FB
PGOOD
1M
VOUT
1.2V
300mA
CFF
22pF
GND
1µF
L1
4.7µH
R2
402k
10µF
VCC
CBST
0.022µF
10µF
R1
402k
3103 TA05a
L1: SUMIDA CDRH4D11NP-4R7N
Efficiency vs Output Current
100
90
EFFICIENCY (%)
80
70
60
50
40
30
20
10
0
0.0001
VIN = 2.5V
VIN = 3.3V
VIN = 5V
0.001
0.01
0.1
OUTPUT CURRENT (A)
1
3103 TA05b
3103f
17
LTC3103
PACKAGE DESCRIPTION
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
DD Package
10-Lead Plastic DFN (3mm × 3mm)
(Reference LTC DWG # 05-08-1699 Rev C)
0.70 ±0.05
3.55 ±0.05
1.65 ±0.05
2.15 ±0.05 (2 SIDES)
PACKAGE
OUTLINE
0.25 ± 0.05
0.50
BSC
2.38 ±0.05
(2 SIDES)
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
3.00 ±0.10
(4 SIDES)
R = 0.125
TYP
6
0.40 ± 0.10
10
1.65 ± 0.10
(2 SIDES)
PIN 1 NOTCH
R = 0.20 OR
0.35 × 45°
CHAMFER
PIN 1
TOP MARK
(SEE NOTE 6)
0.200 REF
0.75 ±0.05
0.00 – 0.05
5
1
(DD) DFN REV C 0310
0.25 ± 0.05
0.50 BSC
2.38 ±0.10
(2 SIDES)
BOTTOM VIEW—EXPOSED PAD
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
3103f
18
LTC3103
PACKAGE DESCRIPTION
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
MSE Package
10-Lead Plastic MSOP, Exposed Die Pad
(Reference LTC DWG # 05-08-1664 Rev H)
BOTTOM VIEW OF
EXPOSED PAD OPTION
1.88 ± 0.102
(.074 ± .004)
5.23
(.206)
MIN
1
0.889 ± 0.127
(.035 ± .005)
0.05 REF
10
0.305 ± 0.038
(.0120 ± .0015)
TYP
RECOMMENDED SOLDER PAD LAYOUT
3.00 ± 0.102
(.118 ± .004)
(NOTE 3)
DETAIL “B”
CORNER TAIL IS PART OF
DETAIL “B” THE LEADFRAME FEATURE.
FOR REFERENCE ONLY
NO MEASUREMENT PURPOSE
10 9 8 7 6
DETAIL “A”
0° – 6° TYP
1 2 3 4 5
GAUGE PLANE
0.53 ± 0.152
(.021 ± .006)
DETAIL “A”
0.18
(.007)
0.497 ± 0.076
(.0196 ± .003)
REF
3.00 ± 0.102
(.118 ± .004)
(NOTE 4)
4.90 ± 0.152
(.193 ± .006)
0.254
(.010)
0.29
REF
1.68
(.066)
1.68 ± 0.102 3.20 – 3.45
(.066 ± .004) (.126 – .136)
0.50
(.0197)
BSC
1.88
(.074)
SEATING
PLANE
0.86
(.034)
REF
1.10
(.043)
MAX
0.17 – 0.27
(.007 – .011)
TYP
0.50
(.0197)
BSC
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.
0.1016 ± 0.0508
(.004 ± .002)
MSOP (MSE) 0911 REV H
3103f
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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
19
LTC3103
TYPICAL APPLICATION
12V to 5V/300mA Regulator with High Efficiency, Ultralow IQ
(1.8µA with VOUT in Regulation, No Load)
VIN
12V
VIN
BST
MODE
SW
LTC3103
CBST
0.022µF
L1
10µH
PGOOD
1M
RUN PGOOD
R2
1.87M
10µF
VCC
FB
CFF
10pF
GND
1µF
VOUT
5V
300mA
47µF
R1
255k
3103 TA06
L1: SUMIDA CDRH4D16FB
RELATED PARTS
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
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
VIN: 2.65V to 10V, VOUT(MIN) = 0.8V, IQ = 10µA, ISD < 1µA, MSOP-8
3103f
20 Linear Technology Corporation
LT 1111 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
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 LINEAR TECHNOLOGY CORPORATION 2011