LTC3423/LTC3424

34234f

The LTC

3423 and LTC3424 are high efficiency, fixed

frequency, step-up DC/DC converters that can regulate
output voltages as low as 1.5V from a single cell. An
applied voltage of at least 2.7V to the V

pin is required

to power the internal control circuitry.

The devices include a 0.16

N-channel MOSFET switch

and a 0.21

P-channel synchronous rectifier. The LTC3423

is intended for applications requiring less than 0.75W of
output power and the LTC3424 for 1.5W or less. Switching
frequencies up to 3MHz are programmed with an external
timing resistor and the oscillator can be synchronized to
an external clock.

Quiescent current is only 38

A in Burst Mode operation,

maximizing battery life in portable applications. Burst
Mode operation is user controlled and can be enabled by
driving the MODE/SYNC pin high. If the MODE/SYNC pin
has either a clock or is driven low then the operation is at
constant fixed frequency.

Other features include a 1

A shutdown, thermal shutdown

and current limit. The LTC3423 and LTC3424 are available
in the 10-lead MSOP package. For applications requiring
an output voltage greater than 2.6V, the LTC3401 and
LTC3402 are recommended without the need of a separate
voltage for the V

pin.

1-Cell to 1.8V at 600mA Step-Up Converter

Pagers

Handheld Instruments

Cordless Phones

Wireless Handsets

GPS Receivers

Battery Backup

1.5V to 5.5V Adjustable Output Voltage

Synchronous Rectification: Up to 95% Efficiency

1A Switch Current (LTC3423) or
2A Switch Current (LTC3424)

Fixed Frequency Operation Up to 3MHz

Wide Input Range: 0.5V to 5.5V (Operating)

Very Low Quiescent Current: 38

A (Burst Mode

Operation)

No External Schottky Diode Required

Synchronizable Switching Frequency

Burst Mode Enable Control

OPTI-LOOP

Compensation

Very Low Shutdown Current: < 1

Small 10-Pin MSOP Package

, LTC and LT are registered trademarks of Linear Technology Corporation.

Burst Mode and OPTI-LOOP are registered trademarks of Linear Technology Corporation.

Efficiency

Low Output Voltage,

3MHz Micropower Synchronous

Boost Converters

DESCRIPTIO

FEATURES

APPLICATIO S

TYPICAL APPLICATIO

LTC3424

SHDN

MODE/SYNC

OUT

GND

C4
470pF

RC
82k

30.1k

R1
110k

R2
249k

2.2

C3
44

C1: TAIYO YUDEN JMK212BJ225MG
C2: TAIYO YUDEN JMK212BJ106MM
C3: TAIYO YUDEN JMK325BJ226MM
L1: SUMIDA CD43-2R2M

= 2.7V TO 5.5V

= 0.9V TO 1.5V

0 = FIXED FREQ

1 = Burst Mode OPERATION

C5
4.7pF

3423/24 TA01

OUT

1.8V
600mA

1
CELL

2.2

3223/24 TA02

Burst Mode

OPERATION

= 1.5V

= 3.3V

OUT

= 1.8V

WITH MBRM120T3 SCHOTTKY

= 0.9V

OUTPUT CURRENT (mA)

EFFICIENCY (%)

100

0.1

100

1000

= 1.2V

LTC3423/LTC3424

34234f

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Input Voltage Range

2.7

5.5

Operating Voltage Range

(Note 4)

0.5

5.5

Output Voltage Adjust Range

1.5

5.5

Feedback Voltage

1.22

1.25

1.28

Feedback Input Current

= 1.25V

Quiescent Current--Burst Mode Operation

= 0V, MODE/SYNC = 3.3V (Note 3)

Quiescent Current--SHDN

SHDN = 0V, Not Including Switch Leakage

0.1

Quiescent Current--Active

= 0V, MODE/SYNC = 0V, R

= 300k (Note 3)

440

800

NMOS Switch Leakage

0.1

PMOS Switch Leakage

0.1

NMOS Switch On Resistance

0.16

PMOS Switch On Resistance

0.21

NMOS Current Limit

LTC3423

1.6

LTC3424

2.8

Maximum Duty Cycle

= 15k

Minimum Duty Cycle

Frequency Accuracy

= 15k

1.6

2.4

MHz

MODE/SYNC Input High

1.4

MODE/SYNC Input Low

0.4

MODE/SYNC Input Current

MODE/SYNC

= 5.5V

0.01

Error Amp Transconductance

I = 5

A to 5

A, V

= V

mhos

(Note 1)

, V

OUT

, V

Voltages .............................. 0.5V to 6V

SW Voltage ................................................. 0.5V to 6V
V

, R

Voltages ......................... 0.5V to (V

OUT

+ 0.3V)

SHDN, FB, MODE Voltages ......................... 0.5V to 6V
Operating Temperature Range (Note 2) .. 40

C to 85

Storage Temperature Range ................. 65

C to 125

Lead Temperature (Soldering, 10 sec).................. 300

JMAX

= 125

= 130

C/ W 1 LAYER BOARD

= 100

C/ W 4 LAYER BOARD

MS PART MARKING

ORDER PART

NUMBER

LTC3423EMS
LTC3424EMS

LTQM

LTQN

The

denotes specifications that apply over the full operating temperature range, otherwise specifications are at T

= 25

= 1.2V, V

= 3.3V, V

OUT

= 1.8V, unless otherwise noted.

ABSOLUTE AXI U RATI GS

PACKAGE/ORDER I FOR ATIO

ELECTRICAL CHARACTERISTICS

Consult LTC Marketing for parts specified with wider operating temperature ranges.

1
2
3
4
5

MODE

GND

10
9
8
7
6

SHDN
V

FB
V

OUT

TOP VIEW

MS PACKAGE

10-LEAD PLASTIC MSOP

LTC3423/LTC3424

34234f

The

denotes specifications that apply over the full operating temperature range, otherwise specifications are at T

= 25

= 1.2V, V

OUT

= 3.3V unless otherwise noted.

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

SHDN Input High

SHDN

= V

OUT

SHDN Input Low

0.4

SHDN Input Current

SHDN

= 5.5V

0.01

ELECTRICAL CHARACTERISTICS

Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.

Note 2: The LTC3423/LTC3424 are guaranteed to meet performance
specifications from 0

C to 70

C. Specifications over the 40

C to 85

operating temperature range are assured by design, characterization and
correlation with statistical process controls.

Note 3: Current is measured into V

since the supply current is

bootstrapped to the V

pin. The outputs are not switching.

Note 4: Once the output is started, the IC is not dependant upon the V

supply.

Switching Waveform on SW Pin

TYPICAL PERFOR A CE CHARACTERISTICS

Transient Response
150mA to 450mA

0.5V/DIV

LOAD

= 500mA

100ns/DIV

3423/24 G01

OUT

1.8V

OUT

= 44

200

s/DIV

3423/24 G02

L = 2.2

OSC

= 1MHz

OUT

100mV/DIV

AC COUPLED

450mA

150mA

Burst Mode Operation
at 500

A Load

Burst Mode Operation
at 10mA Load

OUT

100mV/DIV

AC COUPLED

= 1.2V

1ms/DIV

3423/24 G03

OUT

= 1.8V

OUT

= 44

MODE/SYNC PIN = HIGH

1V/DIV

OUT

100mV/DIV

AC COUPLED

= 1.2V

500

s/DIV

3423/24 G04

OUT

= 1.8V

OUT

= 44

MODE/SYNC PIN = HIGH

1V/DIV

LTC3423/LTC3424

34234f

TYPICAL PERFOR A CE CHARACTERISTICS

Converter Efficiency 1.2V to 1.8V

Efficiency Loss Without Schottky
vs Frequency

LTC3423 Current Limit

EA FB Voltage

Oscillator Frequency Accuracy

PMOS R

DS(ON)

NMOS R

DS(ON)

LTC3424 Current Limit

OUTPUT CURRENT (mA)

EFFICIENCY (%)

100

0.1

100

1000

3223/24 G05

Burst Mode

OPERATION

300MHz

WITH MBRM120T3 SCHOTTKY

3MHz

1MHz

TEMPERATURE (

CURRENT (A)

2.6

2.8

3.0

125

3423/24 G06

2.4

2.2

2.0

105

3.2

3.4

TEMPERATURE (

CURRENT (A) 1.55

1.60

1.65

125

3423/24 G07

1.50

1.45

1.40

105

1.70

1.75

1.80

TEMPERATURE (

VOLTAGE (V)

1.23

1.24

1.25

125

3423/24 G08

1.22

105

1.26

1.27

1.28

TEMPERATURE (

FREQUENCY (MHz)

2.00

125

3423/24 G09

1.95

1.90

105

2.05

2.10

= 15k

TEMPERATURE (

RESISTANCE (

)

0.15

125

3423/24 G10

0.10

0.05

105

0.20

0.25

0.30

OUT

= 1.8V

= 3.3V

TEMPERATURE (

RESISTANCE (

)

0.25

125

3423/24 G11

0.20

0.15

105

0.30

0.35

0.40

OUT

= 1.8V

= 3.3V

FREQUENCY (MHz)

0.2

1.4

2.2

3423/24

G12

0.6

1.0

1.8

2.6

3.0

EFFICIENCY LOSS (%)

= 25

LTC3423/LTC3424

34234f

TYPICAL PERFOR A CE CHARACTERISTICS

Burst Mode Operation Current

(Pin 1): Timing Resistor to Program the Oscillator

Frequency.

OSC

3 10

MODE/SYNC (Pin 2): Burst Mode Select and Oscillator
Synchronization.

MODE/SYNC = High. Enable Burst Mode operation. The
inductor peak inductor current will be 400mA and
return to zero current on each cycle. During Burst Mode
operation the operation is variable frequency, providing
a significant efficiency improvement at light loads. It is
recommended the Burst Mode operation only be en-
tered once the part has started up.

MODE/SYNC = Low. Disable Burst Mode operation and
maintain low noise, constant frequency operation.

MODE/SYNC = External CLK. Synchronization of the
internal oscillator and Burst Mode operation disable. A
clock pulse width of 100ns to 2

s is required to

synchronize.

(Pin 3): Voltage Sense for Internal Circuitry.

PI FU CTIO S

SW (Pin 4): Switch Pin. Connect inductor and optional
Schottky diode here. Minimize trace length to keep EMI
down.

GND (Pin 5): Signal and Power Ground for the IC.

(Pin 6): Power Source for the IC. Typically derived

from a higher voltage power converter. Requires an input
of 2.7V to 5.5V. A 2.2

F ceramic bypass capacitor is

recommended as close to the pins as possible.

OUT

(Pin 7): Output of the Synchronous Rectifier.

FB (Pin 8): Feedback Pin. Connect resistor divider tap
here. The output voltage can be adjusted from 1.5V to
5.5V. The feedback reference voltage is typically 1.25V.

(Pin 9): Error Amp Output. A frequency compensation

network is connected to this pin to compensate the loop.
See the section "Compensating the Feedback Loop" for
guidelines.

SHDN (Pin 10): Shutdown. Grounding this pin shuts down
the IC. Tie to >1V to enable (V

or digital gate output).

During shutdown the output voltage will hold up to V

minus a diode drop due to the body diode of the PMOS
synchronous switch. If the application requires a com-
plete disconnect during shutdown then refer to section
"Output Disconnect".

Shutdown Threshold

TEMPERATURE (

VOLTAGE (V) 0.80

125

3423/24 G13

0.70

0.60

105

0.90

1.00

1.10

0.75

0.65

0.85

0.95

1.05

TEMPERATURE (

CURRENT (

125

3423/24 G14

105

LTC3423/LTC3424

34234f

APPLICATIO S I FOR ATIO

Zero Current Amp. The zero current amplifier monitors the
inductor current to the output and shuts off the synchro-
nous rectifier once the current is below 50mA, preventing
negative inductor current.

Burst Mode Operation

Burst Mode operation is when the IC delivers energy to the
output until it is regulated and then goes into a sleep mode
where the outputs are off and the IC is consuming only
38

A. In this mode, the output ripple has a variable

frequency component with load current and the steady
state ripple will be typically below 3%.

During the period where the device is delivering energy to
the output, the peak current will be equal to 400mA and the
inductor current will terminate at zero current for each cycle.
In this mode the maximum output current is given by:

Amps

OUT MAXBURST

OUT

(

)

Burst Mode operation is user controlled by driving the
MODE/SYNC pin high to enable and low to disable. It is
recommended that Burst Mode operation be entered after
the part has started up.

COMPONENT SELECTION

Inductor Selection

The high frequency operation of the LTC3423/LTC3424
allows the use of small surface mount inductors. The
minimum inductance value is proportional to the operat-
ing frequency and is limited by the following constraints:

H and L

f Ripple V

IN MIN

OUT MAX

IN MIN

OUT MAX

> µ

(

)

(

)

(

)

(

)

(

)

where

k = 3 for LTC3423, 2 for LTC3424

f = Operating Frequency (Hz)

Ripple = Allowable Inductor Current Ripple (A)

IN(MIN)

= Minimum Input Voltage (V)

OUT(MAX)

= Maximum Output Voltage (V)

DETAILED DESCRIPTION

The LTC3423/LTC3424 provides high efficiency, low noise
power for applications such as portable instrumentation
and are ideal for applications that require an output voltage
between 1.5V and 2.6V from a single cell. These products
are an addition to the LTC3401 and LTC3402 family of
synchronous boost converters, with the differences being
the omission of the power good function (PGOOD) and the
addition of a V

input to provide internal power. The IC

will not start up until the applied voltage on the V

pin is

above 2.7V.

The current mode architecture with adaptive slope
compensation provides ease of loop compensation with
excellent transient load response. The low R

DS(ON)

, low

gate charge synchronous switches provides the pulse
width modulation control at high efficiency.

Low Noise Fixed Frequency Operation

Oscillator. The frequency of operation is set through a
resistor from the R

pin to ground where f = 3 · 10

. An

internally trimmed timing capacitor resides inside the IC.
The oscillator can be synchronized with an external clock
inserted on the MODE/SYNC pin. When synchronizing the
oscillator, the free running frequency must be set to
approximately 30% lower than the desired synchronized
frequency. Keeping the sync pulse width below 2

s will

ensure that Burst Mode operation is disabled.

Current Sensing. Lossless current sensing converts the
peak current signal to a voltage to sum in with the internal
slope compensation. This summed signal is compared to
the error amplifier output to provide a peak current control
command for the PWM. The slope compensation in the IC
is adaptive to the input and output voltage. Therefore, the
converter provides the proper amount of slope compensa-
tion to ensure stability and not an excess causing a loss of
phase margin in the converter.

Error Amp. The error amplifier is a transconductance
amplifier with g

= 85

mhos. A simple compensation

network is placed from the V

pin to ground.

Current Limit. The current limit amplifier will shut the
NMOS switch off once the current exceeds its threshold.
The current amplifier delay to output is typically 50ns.

LTC3423/LTC3424

34234f

APPLICATIO S I FOR ATIO

The inductor current ripple is typically set to 20% to 40%
of the maximum inductor current.

For high efficiency, choose an inductor with a high fre-
quency core material, such as ferrite, to reduce core
losses. The inductor should have low ESR (equivalent
series resistance) to reduce the I

R losses and must be

able to handle the peak inductor current at full load without
saturating. Molded chokes or chip inductors usually do
not have enough core to support the peak inductor cur-
rents in the 1A to 2A region. To minimize radiated noise,
use a toroid, pot core or shielded bobbin inductor. See
Table 1 for a list of component suppliers.

Figure 1. Recommended Component Placement. Traces
Carrying High Current Are Direct. Trace Area FB and V

Pins

Are Kept Low. Lead Length to Battery Should be Kept Short

where

= Average Inductor Current

= Peak Inductor Current

The ESR is usually the most dominant factor for ripple in
most power converters. The ripple due to capacitor ESR is
simply given by:

CESR

= I

· R

ESR

Volts

where

ESR

= Capacitor Series Resistance

Low ESR capacitors should be used to minimize output
voltage ripple. For surface mount applications, AVX TPS
series tantalum capacitors and Sanyo POSCAP or Taiyo-
Yuden ceramic capacitors are recommended. For through-
hole applications Sanyo OS-CON capacitors offer low ESR
in a small package size. See Table 2 for a list of component
suppliers.

In some layouts it may be required to place a 1

F low ESR

capacitor as close to the V

OUT

and GND pins as possible.

Table 1. Inductor Vendor Information

SUPPLIER

PHONE

FAX

WEBSITE

Coilcraft

(847) 639-6400

(847) 639-1469

www.coilcraft.com

Coiltronics

(516) 241-7876

(516) 241-9339

www.coiltronics.com

Murata

(814) 237-1431

(814) 238-0490

www.murata.com

(800) 831-9172

Sumida

USA: (847) 956-0666

(847) 956-0702

www.japanlink.com

Japan: 81-3-3607-5111 81-3-3607-5144

sumida

OUT

3423/24 F01

MODE
V

SW
GND

SHDN

OUT

2.7V
TO 5.5V

Output Capacitor Selection

The output voltage ripple has several components. The
bulk value of the capacitor is set to reduce the ripple due
to charge into the capacitor each cycle. The max ripple due
to charge is given by:

V V

BULK

IN OUT

OUT

(

)

Volts

Table 2. Capacitor Vendor Information

SUPPLIER

PHONE

FAX

WEBSITE

AVX

(803) 448-9411

(803) 448-1943

www.avxcorp.com

Sanyo

(619) 661-6322

(619) 661-1055

www.sanyovideo.com

Taiyo Yuden

(408) 573-4150

(408) 573-4159

www.t-yuden.com

Input Capacitor Selection

The input filter capacitor reduces peak currents drawn from
the input source and reduces input switching noise. In most
applications a 3.3

F is sufficient.

Output Diode

The Schottky diode across the synchronous PMOS switch
is not required, but provides a lower drop during the break-
before-make time (typically 20ns) of the NMOS to PMOS
transition. The addition of the Schottky diode will improve
peak efficiency (see graph "Efficiency Loss Without
Schottky vs Frequency"). Use of a Schottky diode such as
a MBRM120T3, 1N5817 or equivalent. Since slow recov-
ery times will compromise efficiency, do not use ordinary
rectifier diodes.

LTC3423/LTC3424

34234f

Operating Frequency Selection

There are several considerations in selecting the operat-
ing frequency of the converter. The first is determining the
sensitive frequency bands that cannot tolerate any spec-
tral noise. For example, in products incorporating RF
communications, the 455kHz IF frequency is sensitive to
any noise, therefore switching above 600kHz is desired.
Some communications have sensitivity to 1.1MHz. In this
case, converter frequencies up to 3MHz may be em-
ployed.

The second consideration is the physical size of the
converter. As the operating frequency goes up, the induc-
tor and filter caps go down in value and size. The trade off
is in efficiency since the switching losses due to gate
charge are going up proportional with frequency.

Another operating frequency consideration is whether the
application can allow "pulse skipping." In this mode, the
minimum on time of the converter cannot support the duty
cycle, so the converter ripple will go up and there will be
a low frequency component of the output ripple. In many
applications where physical size is the main criterion then
running the converter in this mode is acceptable. In
applications where it is preferred not to enter this mode,
then the maximum operating frequency is given by:

MAX NOSKIP

OUT

ON MIN

(

)

where t

ON(MIN)

= minimum on time = 140ns

Reducing Output Capacitance with a Load Feed
Forward Signal

In many applications the output filter capacitance can be
reduced for the desired transient response by having the
device commanding the change in load current, (i.e.
system microcontroller), inform the power converter of
the changes as they occur. Specifically, a "load feed
forward" signal coupled into the V

pin gives the inner

current loop a head start in providing the change in output
current. The transconductance of the LTC3423 converter
at the V

pin with respect to the inductor current is typically

APPLICATIO S I FOR ATIO

130mA/100mV, and the LTC3424 is typically 170mA/
100mV, so the amount of signal injected is proportional to
the anticipated change of inductor current with load. The
outer voltage loop performs the remainder of the correc-
tion, but because of the load feed forward signal, the range
over which it must slew is greatly reduced. This results in
an improved transient response. A logic level feed forward
signal, V

, is coupled through components C5 and R6.

The amount of feed forward signal is attenuated with
resistor R6 and is given by the following relationship:

OUT

1 5

· .

where

OUT

= load current change.

Figure 2

3423/24 F02

LTC3423/LTC3424

SHDN

MODE/SYNC

OUT

GND

LOAD FEED

FORWARD

SIGNAL

3.3nF

OUT

Closing the Feedback Loop

The LTC3423/LTC3424 uses current mode control with
internal adaptive slope compensation. Current mode con-
trol eliminates the 2nd order filter due to the inductor and
output capacitor exhibited in voltage mode controllers,
and simplifies it to a single-pole filter response. The
product of the modulator control to output DC gain plus
the error amp open-loop gain equals the DC gain of the
system.

LTC3423/LTC3424

34234f

APPLICATIO S I FOR ATIO

= G

CONTROLOUTPUT

· G

CONTROL

OUT

2 ·

, G

2000

The output filter pole is given by:

FILTERPOLE

OUT

where C

OUT

is the output filter capacitor.

The output filter zero is given by:

FILTERZERO

ESR

OUT

2 ·

where R

ESR

is the capacitor equivalent series resistance.

A troublesome feature of the boost regulator topology is
the right half plane zero (RHP) and is given by:

L V

RHPZ

· · ·

At heavy loads this gain increase with phase lag can occur
at a relatively low frequency. The loop gain is typically
rolled off before the RHP zero frequency.

Figure 3

1.25V

ERROR

AMP

OUT

3423/24 F03

The typical error amp compensation is shown in Figure 3.
The equations for the loop dynamics are as follows:

which is extremelyclose to DC

POLE

ZERO

POLE

20 10

· ·

Refer to Application Note AN76 for more closed loop
examples.

3423/24 TA03

SHDN

MODE/SYNC

OUT

GND

OUT

= 0.9V TO 1.5V

RB*

C5
1

* SET RB TO FORCE BETA OF

100; RB =

OUT

INMIN

0.7V) · 100

OUTMAX

ZETEX

FMMT717

0 = FIXED FREQ

1 = Burst Mode OPERATION

LTC3423/LTC3424

TYPICAL APPLICATIO

Typical Application with Output Disconnect

LTC3423/LTC3424

34234f

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 represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.

MS Package

10-Lead Plastic MSOP

(Reference LTC DWG # 05-08-1661)

MSOP (MS) 1001

0.53

0.01

(.021

.006)

SEATING

PLANE

0.18

(.007)

1.10

(.043)

MAX

0.17 0.27

(.007 .011)

0.13

0.05

(.005

.002)

0.86

(.034)

REF

0.50

(.0197)

TYP

1 2 3 4 5

4.88

0.10

(.192

.004)

0.497

0.076

(.0196

.003)

REF

7 6

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

0.254

(.010)

TYP

DETAIL "A"

GAUGE PLANE

5.23

(.206)

MIN

3.2 3.45

(.126 .136)

0.889

0.127

(.035

.005)

RECOMMENDED SOLDER PAD LAYOUT

3.05

0.38

(.0120

.0015)

TYP

0.50

(.0197)

BSC

LTC3423

SHDN

MODE/SYNC

OUT

GND

C4
470pF

4.7

82k

30.1k

OSC

= 1MHz

R1
110k

R2
249k

4.7

C3
22

C1: TAIYO YUDEN JMK212BJ225MG
C2: TAIYO YUDEN JMK212BJ475MM
C3: TAIYO YUDEN JMK325BJ226MM
D1: ON SEMICONDUCTOR MBRM120T3
L1: SUMIDA CDRH3D16-4R7M

= 2.7V TO 5.5V

= 0.9V TO 1.5V

0 = FIXED FREQ

1 = Burst Mode OPERATION

C5
4.7pF

3423/24 TA04

OUT

1.8V
300mA

1
CELL

2.2

TYPICAL APPLICATIO

Single Cell to 1.8V at 300mA, 1.8mm High

PACKAGE DESCRIPTIO

LTC3423/LTC3424

34234f

LT/TP 0302 2K · PRINTED IN USA

RELATED PARTS

PART NUMBER

DESCRIPTION

COMMENTS

LT1306

Sync, Fixed Frequency, Step-Up DC/DC Converter

Internal 2A Switches, V

As Low As 1.8V

LT1308A/LT1308B

High Current, Micropower, Single Cell 600kHz DC/DC Converter

5V at 1A from Single Li-Ion Cell

LT1317/LT1317B

Micropower 600kHz PWM DC/DC Converter

As Low As 1.5V, I

= 100

LT1610

1.7MHz, Single Cell Micropower DC/DC Converter

3V at 30mA from 1V, 5V at 200mA from 3.3V

LT1613

1.4MHz, Single Cell DC/DC Converter in ThinSOT

As Low As 1.1V, 3V at 30mA from Single Cell

LT1615

Micropower Step-Up DC/DC Converter in ThinSOT

= 20

A, 1

A Shutdown Current, V

As Low As 1V

LT1949

600kHz, 1A Switch PWM DC/DC Converter

1.1A, 0.5

/30V Internal Switch, V

As Low As 1.8V

LTC3400/LTC3400B

ThinSOT, 600mA, 1.2MHz Boost Converter

92% Efficiency, 0.85V

, 2.6V

OUT

LTC3401

Single Cell, High Current (1A) Micropower, Synchronous

= 0.5V to 5.5V, Up to 97% Efficiency Synchronizable

3MHz Step-Up DC/DC Converter

Oscillator from 100kHz to 3MHz

LTC3402

Single Cell, High Current (2A) Micropower, Synchronous

= 0.5V to 5.5V, Up to 97% Efficiency Synchronizable

3MHz Step-Up DC/DC Converter

Oscillator from 100kHz to 3MHz

ThinSOT is a trademark of Linear Technology Corporation.

LINEAR TECHNOLOGY CORPORATION 2001

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

(408) 432-1900

FAX: (408) 434-0507

www.linear.com

LTC3423

SHDN

MODE/SYNC

OUT

GND

C4
470pF

RC
82k

30.1k

OSC

= 1MHz

R1
110k

R2
249k

2.2

C3
44

C1: TAIYO YUDEN JMK212BJ225MG
C2: TAIYO YUDEN JMK212BJ106MM
C3: TAIYO YUDEN JMK325BJ226MM
D1: ON SEMICONDUCTOR MBRM120T3
D2 TO D7: ZETEX FMND7000 DUAL DIODE
L1: SUMIDA CD43-2R2M

= 2.7V TO 5.5V

= 0.9V TO 1.5V

0 = FIXED FREQ

1 = Burst Mode OPERATION

C5
4.7pF

3423/24 TA05

OUT

1.8V
700mA

1
CELL

2.2

0.1

4.7

0.1

4.7

1.1V
1mA

3.6V
2mA

TYPICAL APPLICATIO

Triple Output Converter

Ð­Ð»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: LTC3423EMS

ÐÐ»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: LTC3423EMS