LTC3429/LTC3429B
600mA, 500kHz Micropower
Synchronous Boost Converter
with Output Disconnect
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FEATURES
DESCRIPTIO
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The LTC®3429/LTC3429B are high efficiency synchronous, fixed frequency, step-up DC/DC converters with true
output load disconnect, inrush current limiting and softstart in a low profile 6-lead ThinSOTTM package. These
devices are capable of supplying 100mA from a single AA
cell input or 250mA from a 2-cell AA with a 3.3V output.
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Up to 96% Efficiency
True Output Load Disconnect
Inrush Current Limiting and Internal Soft-Start
Low Voltage Start-Up: 0.85V
Automatic Burst Mode® Operation with IQ ~ 20µA
Continuous Switching at Light Loads (LTC3429B)
Internal Synchronous Rectifier
Current Mode Control with Internal Compensation
Short-Circuit Protection
500kHz Fixed Frequency Switching
Input Range: 0.5V to 4.4V
Output Range: 2.5V to 4.3V (Up to 5V with Schottky)
Shutdown Current: 4.3V, an external Schottky diode is
required. See the Applications Information.
3429fa
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LTC3429/LTC3429B
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TYPICAL PERFOR A CE CHARACTERISTICS (TA = 25°C unless otherwise specified)
Single-Cell to 3.3V Efficiency
(LTC3429 Only)
2-Cell to 3.3V Efficiency
(LTC3429 Only)
100
Efficiency vs Input Voltage
100
100
100
100
10
90
VOUT = 3.3V
IOUT = 50mA
VIN = 1.2V
70
0.1
VIN = 1.2V
0.01
60
VIN = 2.4V
80
EFFICIENCY (%)
1
EFFICIENCY
70
1
0.1
VIN = 2.4V
VIN = 3V
60
0.01
POWER LOSS (W)
EFFICIENCY
80
90
10
VIN = 1.5V
POWER LOSS (W)
EFFICIENCY (%)
90
EFFICIENCY (%)
VIN = 3V
80
70
60
VIN = 1.5V
POWER LOSS
POWER LOSS
50
40
0.1
40
0.1
0.0001
1000
1
10
100
OUTPUT CURRENT (mA)
40
0.0001
1000
1
10
100
OUTPUT CURRENT (mA)
VIN > VOUT
PMOS LDO
MODE
50
0.001
50
0.001
0.5
3429 G05
Burst Mode Output Current
Threshold vs Input Voltage
(LTC3429 Only)
Li-Ion to 5V Efficiency
(LTC3429 Only)
2-Cell to 5V Efficiency
(LTC3429 Only)
100
100
100
35
10
30
L = 4.7µH
VIN = 3V
90
10
1
VIN = 2.4V
70
0.1
VIN = 3V
0.01
60
EFFICIENCY (%)
VIN = 2.4V
80
1
70
0.1
VIN = 3.6V
VIN = 4.2V
60
POWER LOSS
POWER LOSS
0.001
40
0.1
0.0001
1000
1
10
100
OUTPUT CURRENT (mA)
600
100
VOUT = 3.3V
3429 G07
3.4
1.9 2.4 2.9
INPUT VOLTAGE (V)
4.4
1.9
L = 4.7µH
CURRENT
SINK LOAD
1.7
400
VOUT = 3.3V
300
VOUT = 5V
200
0
0.5
3.9
Minimum Start-Up Input Voltage
vs Load Current
1.5
RESISTOR
LOAD
1.3
1.1
0.9
100
4.4
1.4
3429 G06
INPUT VOLTAGE (V)
OUTPUT CURRENT (mA)
INPUT CURRENT (µA)
VOUT = 5V
3.9
VOUT = 5V
10
0
0.9
500
1.9 2.4 2.9 3.4
INPUT VOLTAGE (V)
VOUT = 3.3V
15
Maximum Load Current
Capability at Output 4% Below
Regulation Point
L = 4.7µH
1.4
20
3429 G04
No Load Input Current
vs Input Voltage (LTC3429 Only)
10
0.9
25
5
0.0001
1000
1
10
100
OUTPUT CURRENT (mA)
3429 G03
1000
0.01
50
0.001
50
40
0.1
VIN = 3.6V
POWER LOSS (W)
EFFICIENCY
80
POWER LOSS (W)
EFFICIENCY (%)
EFFICIENCY
OUTPUT CURRENT (mA)
VIN = 4.2V
90
4.5
3429 G02
3429 G01
100
1.5
2.5
3.5
INPUT VOLTAGE (V)
1
3 3.5
1.5 2 2.5
INPUT VOLTAGE (V)
0.7
4
4.5
3429 G08
0
50
100
OUTPUT CURRENT (mA)
150
3429 G09
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LTC3429/LTC3429B
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TYPICAL PERFOR A CE CHARACTERISTICS (TA = 25°C unless otherwise specified)
Normalized Oscillator Frequency
vs Temperature
Output Voltage vs Temperature
3.44
3.40
Burst Mode Quiescent Current
vs Temperature (LTC3429 Only)
1.02
VIN = 1.5V
IOUT = 30mA
40
35
VOUT (V)
3.36
3.32
3.28
3.24
QUIESCENT CURRENT (µA)
NORMALIZED FREQUECY
1.00
0.98
0.96
0.94
3.20
VOUT = 5V
30
25
VOUT = 3.3V
20
15
10
5
3.16
20 40 60
–60 –40 –29 0
TEMPERATURE (°C)
80
100
0.92
–60 –40 –20 0
20 40 60
TEMPERATURE (°C)
3429 G10
80
0
20 40 60
–60 –40 –20 0
TEMPERATURE (°C)
100
3429 G11
Fixed Frequency and Burst Mode
Operation (LTC3429 Only)
VOUT
100mV/DIV
AC-COUPLED
VSW
1V/DIV
VSW
1V/DIV
100
3429 G12
SW Pin Discontinuous Mode
Antiringing Operation
SW Pin Fixed Frequency
Continuous Mode Operation
80
50mA
IOUT
120µA
VIN = 1.5V
VOUT = 3.3V
IOUT = 50mA
L = 10µH
COUT = 10µF
CPL = 150pF
200ns/DIV
3429 G13
VIN = 1.5V
VOUT = 3.3V
IOUT = 20mA
L = 10µH
COUT = 10µF
CPL = 150pF
200ns/DIV
3429 G14
Inrush Current Control
and Soft-Start
Output Voltage Transient
Response
VOUT
2V/DIV
VOUT
100mV/DIV
AC-COUPLED
INDUCTOR
CURRENT
100mA/DIV
90mA
40mA
VIN = 1.5V
100µs/DIV
VOUT = 3.3V
IOUT = 40mA TO 90mA STEP
L = 10µH
COUT = 10µF
CPL = 150pF
3429 G16
3429 G15
Inrush Current Control
and Soft-Start
VOUT
1V/DIV
IOUT
VIN = 1.5V
5ms/DIV
VOUT = 3.3V
IOUT = 120µA TO 50mA STEP
L = 10µH
COUT = 10µF
CPL = 150pF
INDUCTOR
CURRENT
200mA/DIV
VIN = 1.5V
VOUT = 3.3V
IOUT = 10mA
L = 4.7µH
COUT = 10µF
CPL = 100pF
500µs/DIV
3429 G17
VIN = 2.5V
VOUT = 5V
IOUT = 50mA
L = 4.7µH
COUT = 10µF
CPL = 100pF
2ms/DIV
3429 G18
3429fa
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LTC3429/LTC3429B
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PI FU CTIO S
SHDN = Low: Shutdown, quiescent current < 1µA.
Output capacitor can be completely discharged through
the load or feedback resistors. A 150Ω resistor is
internally connected between SW and VIN.
SW (Pin 1): Switch Pin. Connect inductor between SW
and VIN. Keep these PCB trace lengths as short and wide
as possible to reduce EMI and voltage overshoot. If the
inductor current falls to zero, or SHDN is low, an internal
150Ω antiringing switch is connected from SW to VIN to
minimize EMI.
VOUT (Pin 5): Output Voltage Sense Input and Drain of the
Internal Synchronous Rectifier MOSFET. Bias is derived
from VOUT. PCB trace length from VOUT to the output filter
capacitor(s) should be as short and wide as possible. VOUT
is completely disconnected from VIN when SHDN is low
due to the output disconnect feature.
GND (Pin 2): Signal and Power Ground. Provide a short
direct PCB path between GND and the (–) side of the output
capacitor(s).
FB (Pin 3): Feedback Input to the gm Error Amplifier.
Connect resistor divider tap to this pin. The output voltage
can be adjusted from 2.5V to 5V by:
VIN (Pin 6): Battery Input Voltage. The device gets its
start-up bias from VIN. Once VOUT exceeds VIN, bias
comes from VOUT. Thus, once started, operation is completely independent from VIN. Operation is only limited by
the output power level and the battery’s internal series
resistance.
VOUT = 1.23V • [1 + (R1/R2)]
SHDN (Pin 4): Logic Controlled Shutdown Input.
SHDN = High: Normal free running operation, 500kHz
typical operating frequency.
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BLOCK DIAGRA
L1
+
1V TO 4.4V
6 VIN
1 SW
CIN
+
VOUT
GOOD
–
START-UP
OSC
A
A/B
MUX
WELL
SWITCH
0.45Ω
B
VOUT
2.5V TO 5V
5
SYNC
DRIVE
CONTROL
PWM
CONTROL
RAMP
GEN
500kHz
VIN
2.3V
CPL
(OPTIONAL)
CURRENT
SENSE
Σ
SLOPE
COMP
0.35Ω
R1
PWM
COMPARATOR
–
–
+
FB
Burst Mode
OPERATION
CONTROL
CC
150pF
SHDN
4
SHUTDOWN
CONTROL
SHUTDOWN
+
SLEEP
–
RC
80k
3
1.23V
REF
gm
ERROR
AMP
CP2
2.5pF
COUT
R2
2 GND
3429 BD
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LTC3429/LTC3429B
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OPERATIO
The LTC3429/LTC3429B are 500kHz, synchronous boost
converters housed in a 6-lead SOT-23 package. Able to
operate from an input voltage below 1V, the device features fixed frequency, current mode PWM control for
exceptional line and load regulation. Low RDS(ON) internal
MOSFET switches enable the device to maintain high
efficiency over a wide range of load current. Detailed
descriptions of the different operating modes follow.
Operation can be best understood by referring to the Block
Diagram.
LOW VOLTAGE START-UP
The LTC3429/LTC3429B include an independent start-up
oscillator designed to start up at input voltages of 0.85V
typically. The frequency and duty cycle of the start-up
oscillator are internally set to 150kHz and 67% respectively. In this mode, the IC operates completely open-loop
and the current limit is also set internally to 850mA. Once
the output voltage exceeds 2.3V, the start-up circuitry is
disabled and normal close-loop PWM operation is initiated. In normal mode, the LTC3429/LTC3429B power
themselves from VOUT instead of VIN. This allows the
battery voltage to drop to as low as 0.5V without affecting
the circuit operation. The only limiting factor in the application becomes the ability of the battery to supply sufficient energy to the output. Soft-start and inrush current
limiting are provided during start-up as well as normal
mode operation.
Soft-Start
The LTC3429/LTC3429B provide soft-start by charging an
internal capacitor with a very weak current source. The
voltage on this capacitor, in turn, slowly ramps the peak
inductor current from zero to a maximum value of 850mA.
The soft-start time is typically 2.5ms, the time it takes to
charge the capacitor from zero to 1.35V. However, this
time varies greatly with load current, output voltage and
input voltage (see Typical Performance Characteristics,
Inrush Current Control and Soft-Start). The soft-start
capacitor is discharged completely in the event of a
commanded shutdown or a thermal shutdown. It is discharged only partially in case of a short circuit at the
output.
LOW NOISE FIXED FREQUENCY OPERATION
Oscillator
The frequency of operation is internally set to 500kHz.
Error Amp
The error amplifier is an internally compensated transconductance type (current output) with a transconductance
(gm) = 33 microsiemens. The internal 1.23V reference
voltage is compared to the voltage at the FB pin to generate
an error signal at the output of the error amplifier. A voltage divider from VOUT to ground programs the output
voltage via FB from 2.5V to 5V using the equation:
VOUT = 1.23V • [1 + (R1/R2)]
Current Sensing
Lossless current sensing converts the NMOS switch
current signal to a voltage to be summed with the internal
slope compensation. The summed signal is compared to
the error amplifier output to provide a peak current
control command for the PWM. Peak switch current is
limited to approximately 850mA independent of input or
output voltage. The switch current signal is blanked for
60ns to enhance noise rejection.
Zero Current Comparator
The zero current comparator monitors the inductor current to the output and shuts off the synchronous rectifier
once this current reduces to approximately 27mA. This
prevents the inductor current from reversing in polarity
thereby improving efficiency at light loads.
Antiringing Control
The antiringing control circuitry prevents high frequency
ringing of the SW pin as the inductor current goes to zero
in discontinuous mode. The damping of the resonant
circuit formed by L and CSW (capacitance on SW pin) is
achieved by placing a 150Ω resistor across the inductor.
Synchronous Rectifier
To prevent the inductor current from running away, the
PMOS synchronous rectifier is only enabled when VOUT >
(VIN + 0.1V) and the FB pin is >0.8V.
3429fa
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LTC3429/LTC3429B
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OPERATIO
Thermal Shutdown
An internal temperature monitor will start to reduce the
peak current limit if the die temperature exceeds 125°C. If
the die temperature continues to rise and reaches 160°C,
the part will go into thermal shutdown, all switches will be
turned off and the soft-start capacitor will be reset. The
part will be enabled again when the die temperature drops
by about 15°C.
Burst Mode OPERATION (LTC3429 Only)
Portable devices frequently spend extended time in low
power or standby mode, only switching to high power
consumption when specific functions are enabled. To
improve battery life in these types of products, it is
important to maintain a high power conversion efficiency
over a wide output power range. The LTC3429 provides
automatic Burst Mode operation to increase efficiency of
the power converter at light loads. Burst Mode operation
is initiated if the output load current falls below an internally programmed threshold. This threshold has an inverse dependence on the duty cycle of the converter and
also the value of the external inductor (See Typical Performance Characteristics, Output Current Burst Mode Threshold vs VIN). Once Burst Mode operation is initiated, only
the circuitry required to monitor the output is kept alive
and the rest of the device is turned off. This is referred to
as the sleep state in which the IC consumes only 20µA
from the output capacitor. When the output voltage droops
by about 1% from its nominal value, the part wakes up and
commences normal PWM operation. The output capacitor
recharges and causes the part to re-enter the sleep state
if the output load remains less than the Burst Mode
threshold. The frequency of this intermittent PWM or
burst operation depends on the load current; that is, as the
load current drops further below the burst threshold, the
LTC3429 turns on less frequently. When the load current
increases above the burst threshold, the LTC3429
seamlessly resumes continuous PWM operation. Thus,
Burst Mode operation maximizes the efficiency at very
light loads by minimizing switching and quiescent losses.
However, the output ripple typically increases to about 2%
peak-to-peak. Burst Mode ripple can be reduced, in some
circumstances, by placing a small phase-lead capacitor
(CPL) between VOUT and FB pins (refer to the Block
Diagram). However, this may adversely affect the efficiency and the quiescent current requirement at light
loads. Typical values of CPL range from 15pF to 220pF.
OUTPUT DISCONNECT AND INRUSH LIMITING
The LTC3429/LTC3429B are designed to allow true output
disconnect by eliminating body diode conduction of the
internal PMOS rectifier. This allows VOUT to go to zero
volts during shutdown, drawing zero current from the
input source. It also allows for inrush current limiting at
start-up, minimizing surge currents seen by the input
supply. Note that to obtain the advantage of output disconnect, there must not be an external Schottky diode connected between the SWITCH pin and VOUT.
Board layout is extremely critical to minimize voltage
overshoot on the SWITCH pin due to stray inductance.
Keep the output filter capacitor as close as possible to the
VOUT pin and use very low ESR/ESL ceramic capacitors
tied to a good ground plane. For applications with VOUT
over 4.3V, a Schottky diode is required to limit the peak
SWITCH voltage to less than 6V unless some form of
external snubbing is employed. This diode must also be
placed very close to the pins to minimize stray inductance.
See the Applications Information.
SHORT CIRCUIT PROTECTION
Unlike most boost converters, the LTC3429/LTC3429B
allow their output to be short circuited due to the output disconnect feature. The devices incorporate internal features
such as current limit foldback, thermal regulation and thermal shutdown for protection from an excessive overload
or short circuit. In the event of a short circuit, the internal
soft-start capacitor gets partially discharged. This, in turn,
causes the maximum current limit to foldback to a smaller
value. In addition to this, a thermal regulation circuit starts
to dial back the current limit farther if the die temperature
rises above 125°C. If the die temperature still reaches
160°C, the device shuts off entirely.
VIN > VOUT OPERATION
The LTC3429/LTC3429B will maintain voltage regulation
even if the input voltage is above the output voltage. This
3429fa
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LTC3429/LTC3429B
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OPERATIO
is achieved by terminating the switching of the synchronous PMOS and applying VIN statically on its gate. This
ensures that the slope of the inductor current will reverse
during the time current is flowing to the output. Since the
PMOS no longer acts as a low impedance switch in this
mode, there will be more power dissipation within the IC.
This will cause a sharp drop in the efficiency (see Typical
Performance Characteristics, Efficiency vs VIN). The maximum output current should be limited in order to maintain
an acceptable junction temperature.
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APPLICATIO S I FOR ATIO
PCB LAYOUT GUIDELINES
The high speed operation of the LTC3429/LTC3429B
demands careful attention to board layout. You will not get
advertised performance with careless layout. Figure 2
shows the recommended component placement. A large
ground pin copper area will help to lower the chip temperature. A multilayer board with a separate ground plane is
ideal, but not absolutely necessary.
inductor ripple current. Increasing the inductance above
10µH will increase size while providing little improvement
in output current capability.
The approximate output current capability of the LTC3429
versus inductance value is given in the equation below and
illustrated graphically in Figure 3.
V •D⎞
⎛
IOUT(MAX) = η • ⎜IP – IN ⎟ • (1 – D)
⎝
f • L • 2⎠
where:
VIN
1
SW
VIN 6
2
GND VOUT 5
3
FB SHDN 4
SHDN
VOUT
η = estimated efficiency
IP = peak current limit value (0.6A)
VIN = input (battery) voltage
D = steady-state duty ratio = (VOUT – VIN)/VOUT
f = switching frequency (500kHz typical)
L = inductance value
3429 F02
200
RECOMMENDED COMPONENT PLACEMENT. TRACES
CARRYING HIGH CURRENT ARE DIRECT. TRACE AREA AT
FB PIN IS SMALL. LEAD LENGTH TO BATTERY IS SHORT
COMPONENT SELECTION
Inductor Selection
The LTC3429/LTC3429B can utilize small surface mount
and chip inductors due to its fast 500kHz switching
frequency. Typically, a 4.7µH inductor is recommended
for most applications. Larger values of inductance will
allow greater output current capability by reducing the
160
OUTPUT CURRENT (mA)
Figure 2. Recommended Component Placement
for Single Layer Board
VIN = 1.2V
180
VOUT = 3.3V
140
120
100
VOUT = 5V
80
60
40
20
0
3
5
7
9 11 13 15 17 19 21 23
INDUCTANCE (µH)
3429 F03
Figure 3. Maximum Output Current vs
Inductance Based on 90% Efficiency
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LTC3429/LTC3429B
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APPLICATIO S I FOR ATIO
The inductor current ripple is typically set for 20% to 40%
of the maximum inductor current (IP). High frequency
ferrite core inductor materials reduce frequency
dependent power losses compared to cheaper powdered
iron types, improving efficiency. The inductor should have
low ESR (series resistance of the windings) to reduce the
I2R power losses, and must be able to handle the peak
inductor current without saturating. Molded chokes and
some chip inductors usually do not have enough core to
support the peak inductor currents of 850mA seen on the
LTC3429/LTC3429B. To minimize radiated noise, use a
toroid, pot core or shielded bobbin inductor. See Table 1
for some suggested components and suppliers.
Output and Input Capacitor Selection
Table 1. Recommended Inductors
Low ESR input capacitors reduce input switching noise
and reduce the peak current drawn from the battery. It
follows that ceramic capacitors are also a good choice for
input decoupling and should be located as close as possible to the device. A 10µF input capacitor is sufficient for
virtually any application. Larger values may be used without limitations. Table 2 shows a list of several ceramic
capacitor manufacturers. Consult the manufacturers directly for detailed information on their entire selection of
ceramic capacitors.
PART
L
(µH)
MAX
DCR
mΩ
HEIGHT
(mm)
2.0
2.0
1.8
1.8
3.5
3.5
0.8
0.8
Sumida
www.sumida.com
2.9
2.9
2.9
Coilcraft
www.coilcraft.com
CDRH5D18-4R1
CDRH5D18-100
CDRH3D16-4R7
CDRH3D16-6R8
CR43-4R7
CR43-100
CMD4D06-4R7MC
CMD4D06-3R3MC
4.1
10
4.7
4.7
10
4.7
3.3
57
124
105
170
109
182
216
174
DS1608-472
DS1608-103
DO1608C-472
4.7
10
4.7
60
75
90
VENDOR
D52LC-4R7M
D52LC-100M
4.7
10
84
137
2.0
2.0
Toko
www.tokoam.com
LQH32CN4R7M24
4.7
195
2.2
Murata
www.murata.com
Low ESR (equivalent series resistance) capacitors should
be used to minimize the output voltage ripple. Multilayer
ceramic capacitors are an excellent choice as they have
extremely low ESR and are available in small footprints. A
4.7µF to 15µF output capacitor is sufficient for most
applications. Larger values up to 22µF may be used to
obtain extremely low output voltage ripple and improve
transient response. An additional phase lead capacitor
may be required with output capacitors larger than 10µF
to maintain acceptable phase margin. X5R and X7R
dielectric materials are preferred for their ability to maintain capacitance over wide voltage and temperature ranges.
Table 2. Capacitor Vendor Information
SUPPLIER
WEBSITE
AVX
www.avxcorp.com
Murata
www.murata.com
Taiyo Yuden
www.t-yuden.com
3429fa
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LTC3429/LTC3429B
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TYPICAL APPLICATIO S
Applications Where VOUT > 4.3V
improvement but will negate the output disconnect feature. If output disconnect is required, an active snubber
network is suggested as shown below. Examples of Schottky diodes are: MBR0520L, PMEG2010EA, 1N5817 or
equivalent.
When the output voltage is programmed above 4.3V, it is
necessary to add a Schottky diode either from SW to VOUT,
or to add a snubber network in order to maintain an
acceptable peak voltage on the SW pin. The Schottky diode
between SW and VOUT will provide a peak efficiency
Application Circuit for VOUT > 4.3V Where Inrush Current Limiting and Output Disconnect are Required
Li-Ion to 5V Efficiency
D1*
100
+
Li-Ion
C1
4.7µF
1
6
MP1
SW
VIN
VOUT
OFF ON
SHDN
FB
3
R2
604k
GND
2
C2
10µF
3429 TA04
VIN = 4.2V
90
10
EFFICIENCY
*LOCATE COMPONENTS CLOSE TO THE PIN
C1: TAIYO YUDEN X5R JMK212BJ475MM
C2: TAIYO YUDEN X5R JMK212BJ106MM
D1: MOTOROLA MBR0520L
L1: COILCRAFT D0160C-472
MP1: ZETEX ZXM61P02F
VIN = 3.6V
80
1
70
0.1
VIN = 3.6V
VIN = 4.2V
60
0.01
POWER LOSS (W)
R1
1.82M
LTC3429
4
VOUT
5V
250mA
5
100
C3*
0.22µF
EFFICIENCY (%)
VIN
2.7V TO 4.2V
L1
4.7µH
POWER LOSS
50
40
0.1
0.001
0.0001
1000
1
10
100
OUTPUT CURRENT (mA)
3429 TA04b
Application Circuit for VOUT > 4.3V Where Inrush Current Limiting and Output Disconnect are Not Required
L1
4.7µH
+
100
2 AA
CELL
C1
4.7µF
6
SW
VIN
VOUT
5
4
SHDN
FB
3
GND
2
R1
1.82M
R2
604k
VOUT
5V
150mA
C2
10µF
3429 TA05
*LOCATE COMPONENTS CLOSE TO THE PIN
C1: TAIYO YUDEN X5R JMK212BJ475MM
C2: TAIYO YUDEN X5R JMK212BJ106MM
D1: MOTOROLA MBR0520L
L1: COILCRAFT D0160C-472
VIN = 3V
90
80
70
EFFICIENCY
10
VIN = 2.4V
1
VIN = 2.4V
0.1
VIN = 3V
0.01
60
POWER LOSS (W)
LTC3429
OFF ON
100
1
EFFICIENCY (%)
VIN
2-Cell to 5V Efficiency
D1*
POWER LOSS
50
40
0.1
0.001
1
10
100
OUTPUT CURRENT (mA)
0.0001
1000
3429 TA05b
3429fa
10
LTC3429/LTC3429B
U
PACKAGE DESCRIPTIO
S6 Package
6-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1636)
0.62
MAX
2.90 BSC
(NOTE 4)
0.95
REF
1.22 REF
3.85 MAX 2.62 REF
1.4 MIN
2.80 BSC
1.50 – 1.75
(NOTE 4)
PIN ONE ID
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
0.30 – 0.45
6 PLCS (NOTE 3)
0.95 BSC
0.80 – 0.90
0.20 BSC
0.01 – 0.10
1.00 MAX
DATUM ‘A’
0.30 – 0.50 REF
0.09 – 0.20
(NOTE 3)
1.90 BSC
S6 TSOT-23 0302
NOTE:
1. DIMENSIONS ARE IN MILLIMETERS
2. DRAWING NOT TO SCALE
3. DIMENSIONS ARE INCLUSIVE OF PLATING
4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
5. MOLD FLASH SHALL NOT EXCEED 0.254mm
6. JEDEC PACKAGE REFERENCE IS MO-193
3429fa
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.
11
LTC3429/LTC3429B
U
TYPICAL APPLICATIO
Single AA Cell to 2.5V Synchronous Boost Converter
Single AA Cell to 3.3V
L1
4.7µH
L1
4.7µH
+
SINGLE
AA CELL
C1
4.7µF
1
6
SW
VIN
VOUT
5
R1
1.02M
LTC3429
OFF ON
4
SHDN
FB
VOUT
2.5V
130mA
3
R2
1.02M
GND
2
SINGLE
AA CELL
+
C1
4.7µF
1
6
SW
VIN
VOUT
LTC3429
C2
10µF
OFF ON
4
SHDN
FB
3
R1
1.02M
R2
604k
GND
2
3429 TA03
C1: TAIYO YUDEN X5R JMK212BJ475MM
C2: TAIYO YUDEN X5R JMK212BJ106MM
L1: COILCRAFT D0160C-472
VOUT
3.3V
100mA
5
C2
10µF
3429 TA06
C1: TAIYO YUDEN X5R JMK212BJ475MM
C2: TAIYO YUDEN X5R JMK212BJ106MM
L1: COILCRAFT D0160C-472
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DESCRIPTION
COMMENTS
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1A/2A (ISW), 3MHz, Synchronous Step-Up
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MS10
LTC3421
3A (ISW), 3MHz, Synchronous Step-Up DC/DC
Converter with Output Disconnect
95% Efficiency, VIN: 0.5V to 4.5V, VOUT(MAX) = 5.25V, IQ = 12µA,
ISD < 1µA, QFN24
LTC3425
5A (ISW), 8MHz, 4-Phase Synchronous Step-Up DC/DC
Converter with Output Disconnect
95% Efficiency, VIN: 0.5V to 4.5V, VOUT(MAX) = 5.25V, IQ = 12µA,
ISD < 1µA, QFN32
LT3464
85mA (ISW), High Efficiency Step-Up DC/DC Converter
with Integrated Schottky and PNP Disconnect
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No RSENSE is a trademark of Linear Technology Corporation.
3429fa
12
Linear Technology Corporation
LT/TP 1104 1K REV A • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
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