Datasheet LM3354MMX-5.0, LM3354MMX-3.3, LM3354MMX-1.8, LM3354MM-5.0, LM3354MM-4.1 Datasheet (NSC)

LM3354
Regulated 90mA Buck-Boost Switched Capacitor DC/DC
Converter

General Description

The LM3354 is a CMOS switched capacitor DC/DC con­verter that produces a regulated output voltage by automati­cally stepping up (boost) or stepping down (buck) the input
voltage. It accepts an input voltage between 2.5V and 5.5V.
The LM3354 is available with standard output voltages of

1.8V, 3.3V, 4.1V (ideal forwhite LED applications), and 5.0V.
If other output voltage options between 1.8V and 5.0V are
desired, please contact your National Semiconductor repre­sentative.

The LM3354’s proprietary buck-boost architecture enables
up to 90mA of load current at an average efficiency greater
than 75%. Typical operating current is only 375 µA and the
typical shutdown current is only 2.3 µA.

The LM3354 is available in a 10-pin MSOP package. This
package has a maximum height of only 1.1 mm.

The high efficiency of the LM3354, low operating and shut­down currents, small package size, and the small size of the
overall solution make this device ideal for battery powered,
portable, and hand-held applications.

See the LM3352 for up to 200mA of output current or the
LM3355 for up to 50mA of output current.

Features

n Regulated V

OUT

with±3% (5.0V, 4.1V, and 3.3V

options) or

±

4% (1.8V option) accuracy

n Standard output voltages of 1.8V, 3.3V, 4.1V, and 5.0V
n Custom output voltages available from 1.8V to 5.0V in

100 mV increments with volume order

n 2.5V to 5.5V input voltage range
n Up to 90mA (5.0V, 4.1V, and 1.8V options) or 70mA

(3.3V option) output current

n

>

75% average efficiency

n Uses few, low-cost external components
n Very small solution size
n 375 µA typical operating current
n 2.3 µA typical shutdown current
n 1 MHz typical switching frequency
n Architecture and control methods provide high load

current and good efficiency

n MSOP-10 package
n Over-temperature protection

Applications

n White LED display backlights
n 1-cell Lilon battery-operated equipment including PDAs,

hand-held PCs, cellular phones

n Flat panel displays
n Hand-held instruments
n Li-Ion, NiCd, NiMH, or alkaline battery powered systems

Typical Operating Circuit

DS200188-1

February 2002

LM3354 Regulated 90mA Buck-Boost Switched Capacitor DC/DC Converter

© 2002 National Semiconductor Corporation DS200188 www.national.com

Connection Diagram

Ordering Information

Order Number Package Type NSC Package Drawing Supplied As

LM3354MMX-5.0 MSOP-10 MUB10A 3.5k Units, Tape and Reel
LM3354MM-5.0 MSOP-10 MUB10A 1k Units, Tape and Reel
LM3354MMX-4.1 MSOP-10 MUB10A 3.5k Units, Tape and Reel
LM3354MM-4.1 MSOP-10 MUB10A 1k Units, Tape and Reel
LM3354MMX-3.3 MSOP-10 MUB10A 3.5k Units, Tape and Reel
LM3354MM-3.3 MSOP-10 MUB10A 1k Units, Tape and Reel
LM3354MMX-1.8 MSOP-10 MUB10A 3.5k Units, Tape and Reel
LM3354MM-1.8 MSOP-10 MUB10A 1k Units, Tape and Reel

Pin Description

Pin Number Name Function

1V

IN

Input Supply Voltage
2 C1− Negative Terminal for C1
3 C1+ Positive Terminal for C1
4 GND Ground
5 GND Ground
6C

FIL

Filter Capacitor, a 1µF capacitor is recommended.
7SD

Shutdown, active low
8V

OUT

Regulated Output Voltage
9 C2− Negative Terminal for C2

10 C2+ Positive Terminal for C2

DS200188-2

Top View

MSOP-10 Pin Package

See NS Package Number MM

LM3354

www.national.com 2

Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.

All Pins −0.5V to 5.6V
Power Dissipation (T

A

= 25˚C)

(Note 2) Internally Limited

T

JMAX

(Note 2) 150˚C

θ

JA

(Note 2) 250˚C/W
Storage Temperature −65˚C to +150˚C
Lead Temperature (Soldering, 5 sec.) 260˚C

ESD Rating (Note 3)

Human Body Model
Machine Model

1.5 kV
100V

Operating Ratings

Input Voltage (VIN) 2.5V to 5.5V
Output Voltage (V

OUT

) 1.8V to 5.0V

Ambient Temperature (T

A

) (Note 2) −40˚C to +85˚C

Junction Temperature (T

J

) (Note 2) −40˚C to +120˚C

Electrical Characteristics

Limits in standard typeface are for TA= 25˚C, and limits in boldface type apply over the full operating temperature range. Un­less otherwise specified: C

1=C2

= 0.33 µF; CIN= 10 µF; C

OUT

= 10 µF; C

FIL

= 1 µF; VIN= 3.5V.

Parameter Conditions Min

(Note 5)

Typ

(Note 4)

Max

(Note 5)

Units

LM3354-5.0

Output Voltage (V

OUT

) 3.4V<V

IN

<

5.5V;

1mA

<

I

LOAD

<

90 mA

4.85/4.8 5.0 5.15/5.2

V

3.1V

<

V

IN

<

5.5V;

1mA

<

I

LOAD

<

55 mA

4.85/4.8 5.0 5.15/5.2

2.9V

<

V

IN

<

5.5V;

1mA

<

I

LOAD

<

30 mA

4.85/4.8 5.0 5.15/5.2

Efficiency I

LOAD

=15mA 85

%

I

LOAD

= 40 mA, VIN= 3.8V 85

Output Voltage Ripple
(Peak-to-Peak)

I

LOAD

=50mA

C

OUT

= 10 µF ceramic

75 mV

P-P

LM3354-4.1

Output Voltage (V

OUT

) 2.9V<V

IN

<

5.5V;

1mA

<

I

LOAD

<

90 mA

3.977/3.936 4.1 4.223/4.264
V

2.5V

<

V

IN

<

5.5V;

1mA

<

I

LOAD

<

40 mA

3.977/3.936 4.1 4.223/4.264

Efficiency I

LOAD

=15mA 80

%

I

LOAD

=70mA 75

Output Voltage Ripple
(Peak-to-Peak)

I

LOAD

=50mA

C

OUT

= 10 µF ceramic

75 mV

P-P

LM3354-3.3

Output Voltage (V

OUT

) 2.9V<V

IN

<

5.5V;

1mA

<

I

LOAD

<

70 mA

3.201/3.168 3.3 3.399/3.432
V

2.5V

<

V

IN

<

5.5V;

1mA

<

I

LOAD

<

70 mA

3.201/3.168 3.3 3.399/3.432

Efficiency I

LOAD

=15mA 90

%

I

LOAD

=70mA 70

Output Voltage Ripple
(Peak-to-Peak)

I

LOAD

=50mA

C

OUT

= 10 µF ceramic

75 mV

P-P

LM3354-1.8

Output Voltage (V

OUT

) 2.9V<V

IN

<

5.5V;

1mA

<

I

LOAD

<

90 mA

1.728/1.710 1.8 1.872/1.89
V

2.5V

<

V

IN

<

5.5V;

1mA

<

I

LOAD

<

80 mA

1.728/1.710 1.8 1.872/1.89

Efficiency I

LOAD

=15mA 75

%

I

LOAD

=70mA 70

Output Voltage Ripple
(Peak-to-Peak)

I

LOAD

=50mA

C

OUT

= 10 µF ceramic

25 mV

P-P

LM3354

www.national.com3

Electrical Characteristics (Continued)

Limits in standard typeface are for TA= 25˚C, and limits in boldface type apply over the full operating temperature range. Un­less otherwise specified: C

1=C2

= 0.33 µF; CIN= 10 µF; C

OUT

= 10 µF; C

FIL

= 1 µF; VIN= 3.5V.

Parameter Conditions Min

(Note 5)

Typ

(Note 4)

Max

(Note 5)

Units

LM3354-ALL OUTPUT VOLTAGE VERSIONS

Operating Quiescent
Current

Measured at Pin V

IN

;

I

LOAD

= 0A (Note 6)

375 475 µA

Shutdown Quiescent
Current

SD Pin at 0V (Note 7) 2.3 5 µA

Switching Frequency 0.6 1 1.4 MHz
SD Input Threshold Low 2.5V

<

V

IN

<

5.5V 0.2 V

IN

V

SD Input Threshold High 2.5V

<

V

IN

<

5.5V 0.8 V

IN

V

SD Input Current Measured at SD Pin;

SD Pin = V

IN

= 5.5V

0.3 µA

Note 1: “Absolute Maximum Ratings” indicate limits beyond which damage to the device may occur. Operating Ratings are conditions for which the device is
intended to be functional, but device parameter specifications may not be guaranteed. For guaranteed specifications and test conditions, see “Electrical
Characteristics”.

Note 2: As long as T

A

≤ +85˚C, all electrical characteristics hold true and the junction temperature should remain below +120˚C except for the 5V output option.

The 5V option requires that T

A

≤ +60˚C.

Note 3: The human body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin. The machine model is a 200 pF capacitor discharged
directly into each pin.

Note 4: Typical numbers are at 25˚C and represent the most likely norm.
Note 5: All limits guaranteed at room temperature (standard typeface) and at temperature extremes (bold typeface). All room temperature limits are 100% tested

or guaranteed through statisticalanalysis.All limits at temperature extremes are guaranteed by correlation using standard Statistical Quality Control methods (SQC).
All limits are used to calculate Average Outgoing Quality Level (AOQL).

Note 6: The V

OUT

pin is forced to 200 mV above the typical V

OUT

. This is to insure that the internal switches are off.

Note 7: The output capacitor C

OUT

is fully discharged before measurement.

Typical Performance Characteristics Unless otherwise specified T

A

= 25˚C.

V

OUT

vs. V

IN

DS200188-41

V

OUT

vs. V

IN

DS200188-42

LM3354

www.national.com 4

Typical Performance Characteristics Unless otherwise specified T

A

= 25˚C. (Continued)

V

OUT

vs. V

IN

DS200188-4

V

OUT

vs. V

IN

DS200188-5

V

OUT

vs. V

IN

DS200188-34

V

OUT

vs. V

IN

DS200188-35

V

OUT

vs. V

IN

DS200188-36

V

OUT

vs. V

IN

DS200188-37

LM3354

www.national.com5

Typical Performance Characteristics Unless otherwise specified T

A

= 25˚C. (Continued)

Efficiency vs. V

IN

DS200188-20

Efficiency vs. V

IN

DS200188-38

Efficiency vs. V

IN

DS200188-39

Efficiency vs. V

IN

DS200188-43

Operating Quiescent
Current vs. V

IN

DS200188-24

Switching Frequency vs. V

IN

DS200188-23

LM3354

www.national.com 6

Typical Performance Characteristics Unless otherwise specified T

A

= 25˚C. (Continued)

Maximum V

OUT

Ripple vs. C

OUT

DS200188-32

Maximum V

OUT

Ripple vs. C

OUT

DS200188-30

Load Transient Response

DS200188-14

LM3354

www.national.com7

Applications Information

Operating Principle

The LM3354 is designed to provide a step-up/step-down
voltage regulation in battery powered systems. It combines
switched capacitor circuitry, reference, comparator, and
shutdown logic in a single 10-pin MSOP package. The
LM3354 can provide a regulated voltage between 1.8V and

5.0V from an input voltage between 2.5V and 5.5V. It can
supply a load current up to 90 mA (refer to

Electrical Char-

acteristics

).

As shown in

Figure 1

, the LM3354 employs two feedback
loops to provide regulation in the most efficient manner
possible. The first loop is from V

OUT

through the comparator

COMP, the AND gate G

1

, the phase generator, and the

switch array. The comparator’s output is high when V

OUT

is

less than the reference V

REF

. Regulation is provided by
gating the clock to the switch array. In this manner, charge is
transferred to the output only when needed. The second
loop controls the gain configuration of the switch array. This
loop consists of the comparator, the digital control block, the
phase generator, and the switch array. The digital control
block computes the most efficient gain from a set of five
gains based on inputs from the A/D and the comparator. The
gain signal is sent to the phase generator which then sends
the appropriate timing and configuration signals to the switch
array.This dual loop provides regulation over a wide range of
loads efficiently.

Since efficiency is automatically optimized, the curves for
V

OUT

vs. VINand Efficiency vs. VINin the Typical Perfor­mance Characteristics section exhibit small variations. The
reason is that as input voltage or output load changes, the
digital control loops are making decisions on how to optimize
efficiency. As the switch array is reconfigured, small varia­tions in output voltage and efficiency result. In all cases
where these small variations are observed, the part is oper­ating correctly; minimizing output voltage changes and opti­mizing efficiency.

Charge Pump Capacitor Selection

A 0.33 µF ceramic capacitor is suggested for C1 and C2. To
ensure proper operation over temperature variations, an
X7R dielectric material is recommended.

Filter Capacitor Selection

a) CAPACITOR TECHNOLOGIES

The three major technologies of capacitors that can be used
as filter capacitors for LM3354 are: i) tantalum, ii) ceramic
and iii) polymer electrolytic technologies.

i) Tantalum

Tantalum capacitors are widely used in switching regulators.
Tantalum capacitors have the highest CV rating of any tech­nology; as a result, high values of capacitance can be ob­tained in relatively small package sizes. It is also possible to
obtain high value tantalum capacitors in very low profile
(

<

1.2 mm) packages. This makes the tantalums attractive
for low-profile, small size applications. Tantalums also pos­sess very good temperature stability; i.e., the change in the
capacitance value, and impedance over temperature is rela­tively small. However, the tantalum capacitors have relatively
high ESR values which can lead to higher voltage ripple and
their frequency stability (variation over frequency) is not very
good, especially at high frequencies (

>

1 MHz).

ii) Ceramic

Ceramic capacitors have the lowest ESR of the three tech­nologies and their frequency stability is exceptionally good.
These characteristics make the ceramics an attractive
choice for low ripple, high frequency applications. However,
the temperature stability of the ceramics is bad, except for
the X7R and X5R dielectric types. High capacitance values
(

>

1 µF) are achievable from companies such as
Taiyo-yuden which are suitable for use with regulators. Ce­ramics are taller and larger than the tantalums of the same
capacitance value.

iii) Polymer Electrolytic

Polymer electrolytic is a third suitable technology. Polymer
capacitors provide some of the best features of both the
ceramic and the tantalum technologies. They provide very
low ESR values while still achieving high capacitance val­ues. However, their ESR is still higher than the ceramics,
and their capacitance value is lower than the tantalums of
the same size. Polymers offer good frequency stability (com-

DS200188-3

FIGURE 1. Block Diagram

LM3354

www.national.com 8

Filter Capacitor Selection (Continued)

parable to ceramics) and good temperature stability (compa­rable to tantalums). The Aluminum Polymer Electrolytics
offered by Cornell-Dubilier and Panasonic, and the POS­CAPs offered by Sanyo fall under this category.

Table 1

compares the features of the three capacitor tech-

nologies.

TABLE 1. Comparison of Capacitor Technologies

Ceramic Tantalum

Polymer

Electrolytic

ESR Lowest High Low
Relative Height Low for Small Values (

<

10 µF); Taller for

Higher Values

Lowest Low

Relative Footprint Large Small Largest
Temperature Stability X7R/X5R-Acceptable Good Good
Frequency Stability Good Acceptable Good
V

OUT

Ripple Magnitude

@

<

50 mA Low High Low

V

OUT

Ripple Magnitude

@

>

100 mA Low Slightly Higher Low

dv/dt of V

OUT

Ripple@All Loads Lowest High Low

b) CAPACITOR SELECTION

i) Output Capacitor (C

OUT

)

The output capacitor C

OUT

directly affects the magnitude of

the output ripple voltage so C

OUT

should be carefully se-

lected. The graphs titled V

OUT

Ripple vs. C

OUT

in the Typical
Performance Characteristics section show how the ripple
voltage magnitude is affected by the C

OUT

value and the
capacitor technology. These graphs are taken at the gain at
which worst case ripple is observed. In general, the higher
the value of C

OUT

, the lower the output ripple magnitude. At

lighter loads, the low ESR ceramics offer a much lower V

OUT

ripple than the higher ESR tantalums of the same value. At
higher loads, the ceramics offer a slightly lower V

OUT

ripple
magnitude than the tantalums of the same value. However,
the dv/dt of the V

OUT

ripple with the ceramics and polymer
electrolytics is much lower than the tantalums under all load
conditions. The tantalums are suggested for very low profile,
small size applications. The ceramics and polymer electro­lytics are a good choice for low ripple, low noise applications
where size is less of a concern.

ii) Input Capacitor (C

IN

)

The input capacitor C

IN

directly affects the magnitude of the

input ripple voltage, and to a lesser degree the V

OUT

ripple.

A higher value C

IN

will give a lower VINripple. To optimize

low input and output ripple as well as size a 10 µF polymer
electrolytic or ceramic, or 15 µF tantalum capacitor is rec­ommended. This will ensure low input ripple at 90 mA load
current. If lower currents will be used or higher input ripple
can be tolerated then a smaller capacitor may be used to
reduce the overall size of the circuit. The lower ESR ceram­ics and polymer electrolytics achieve a lower V

IN

ripple than
the higher ESR tantalums of the same value. Tantalums
make a good choice for small size, very low profile applica­tions. The ceramics and polymer electrolytics are a good
choice for low ripple, low noise applications where size is
less of a concern. The 10 µF polymer electrolytics are physi­cally much larger than the 15 µF tantalums and 10 µF
ceramics.

iii) C

FIL

A 1 µF, X7R ceramic capacitor should be connected to pin
C

FIL

. This capacitor provides the filtering needed for the

internal supply rail of the LM3354.
Of the different capacitor technologies, a sample of vendors

that have been verified as suitable for use with the LM3354
are shown in

Table 2

.

TABLE 2. Capacitor Vendor Information

Manufacturer Tel Fax Website

Ceramic Taiyo-yuden [phone] [phone] www.t-yuden.com

AVX [phone] [phone] www.avxcorp.com
Sprague/Vishay [phone] [phone] www.vishay.com

Tantalum

Nichicon [phone] [phone] www.nichicon.com

Polymer Electrolytic Cornell-Dubilier (ESRD) [phone] [phone] www.cornell-dubilier.com

Sanyo (POSCAP) [phone] [phone] www.sanyovideo.com

LM3354

www.national.com9

Maximum Load Under Start-Up

Due to the LM3354’s unique start-up sequence, it is not
able to start up under all load conditions. Starting with 60
mA or less will allow the part to start correctly under any
temperature or input voltage conditions. After the output is
in regulation, any load up to the maximum as specified in
the Electrical Characteristics may be applied. Using a
Power On Reset circuit, such as the LP3470, is recom­mended if greater start up loads are expected. Under
certain conditions the LM3354 can start up with greater
load currents without the use of a Power On Reset Circuit.

Thermal Protection

During output short circuit conditions, the LM3354 will draw
high currents causing a rise in the junction temperature.
On-chip thermal protection circuitry disables the charge
pump action once the junction temperature exceeds the
thermal trip point, and re-enables the charge pump when the
junction temperature falls back to a safe operating point.

Typical Application Circuits

DS200188-33

FIGURE 2. Basic Buck/Boost Regulator

DS200188-15

FIGURE 3. Low Output Noise and Ripple Buck/Boost Regulator

DS200188-40

FIGURE 4. White LED Driver

LM3354

www.national.com 10

Driving Light Emitting Diodes

The LM3354 can be used to drive LED’s of nearly any color.
The 4.1V option is ideal for driving the White LED’s required
for the backlight of small color displays.

Figure 4

shows the
circuit used to power White LED’s. The LED current is set by
the resistors R

B

by using the equation I

LED

= (4.1V − VF)/R

B

where VFis the typical forward voltage drop of the LED used.
The brightness of the diodes may be controlled using the

shutdown pin. A PWM signal on the shutdown pin may be
used to adjust the brightness by varying the duty cycle. A
signal between 60Hz and 200Hz may be used for best
linearity. In this case the equivalent LED current is approxi-

mately equal to the maximum current multiplied by the duty
cycle. Using frequencies above 200Hz may cause less linear
results as the charge and discharge time of the output
capacitor becomes more significant.

Layout Considerations

Due to the 1 MHz typical switching frequency of the LM3354,
careful board layout is a must. It is important to place the
capacitors as close to the IC as possible and to keep the
traces between the capacitors and the IC short and direct.
Use of a ground plane is recommended.

Figure 5

shows a

typical layout as used in the LM3354 evaluation board.

DS200188-16

FIGURE 5. Typical Layout, Top View (magnification 1.5X)

LM3354

www.national.com11

Physical Dimensions inches (millimeters) unless otherwise noted

LIFE SUPPORT POLICY

NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:

1. Life support devices or systems are devices or
systems which, (a) are intended for surgical implant
into the body, or (b) support or sustain life, and
whose failure to perform when properly used in
accordance with instructions for use provided in the
labeling, can be reasonably expected to result in a
significant injury to the user.

2. A critical component is any component of a life
support device or system whose failure to perform
can be reasonably expected to cause the failure of
the life support device or system, or to affect its
safety or effectiveness.

National Semiconductor
Corporation

Americas
Email: [e-mail]

National Semiconductor
Europe

Fax: [phone]

Email: [e-mail]
Deutsch Tel: [phone]
English Tel: [phone]
Français Tel: [phone]

National Semiconductor
Asia Pacific Customer
Response Group

Tel: [phone]
Fax: [phone]
Email: [e-mail]

National Semiconductor
Japan Ltd.

Tel: [phone]
Fax: [phone]

www.national.com

MSOP-10 Pin Package (MM)

For Ordering, Refer to Ordering Information Table

NS Package Number MUB10A

LM3354 Regulated 90mA Buck-Boost Switched Capacitor DC/DC Converter

National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.