Datasheet NCP1403SNT1G Datasheet

NCP1403

15 V/50 mA PFM Step-Up
DC-DC Converter

The NCP1403 is a monolithic PFM step-up DC-DC converter. This
device is designed to boost a single Lithium or two cell AA/AAA
battery voltage up to 15 V (with internal MOSFET) output for
handheld applications. A pullup Chip Enable feature is built with this
device to extend battery-operating life. Besides, the device can also be
incorporated in step-down, and voltage-inverting configurations.
This device is available in space-saving TSOP-5 package.

Features

•82% Efficiency at V

•78% Efficiency at V

•Low Operating Current of 19 mA (No Switching)

•Low Shutdown Current of 0.3 mA

•Low Startup Voltage of 1.3 V Typical at 0 mA

•Output Voltage up to 15 V with Built-in 16 V MOSFET Switch

•PFM Switching Frequency up to 300 kHz

•Chip Enable

•Low Profile and Minimum External Parts

•Micro Miniature TSOP-5 Package

•Pb-Free Package is Available

= 15 V, I

OUT

= 15 V, I

OUT

= 50 mA, VIN = 5.0 V

OUT

= 30 mA, VIN = 3.6 V

OUT

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5

1

TSOP-5

SN SUFFIX

CASE 483

MARKING DIAGRAM AND

PIN CONNECTIONS

CE

FB

VDD

1

G

2

3

5

DCEAYWG

LX

GND

4

Typical Applications

•LCD Bias

•Personal Digital Assistants (PDA)

•Digital Still Camera

•Handheld Games

•Hand-held Instrument

(Top View)

DCE =Specific Device Marking
A = Assembly Location
Y = Year
W = Work Week
G = Pb-Free Package
(Note: Microdot may be in either location)

ORDERING INFORMATION

Device Package Shipping

NCP1403SNT1 TSOP-5 3000/Tape & Reel

NCP1403SNT1G TSOP-5

(Pb-Free)

†For information on tape and reel specifications,

including part orientation and tape sizes, please
refer to our Tape and Reel Packaging Specifications
Brochure, BRD8011/D.

3000/Tape & Reel

†

© Semiconductor Components Industries, LLC, 2007

May, 2007 - Rev. 6

1 Publication Order Number:

NCP1403/D

NCP1403

V

1.8 V to 5.5 V

V

IN

2.7 V to 5.5 V

C

4.7 mF
10 V

Enable

IN

Enable

1

C

1

10 mF

L

47 mH

+

CE

1

FB

2

VDD

3

NCP1403

LX

5

750 pF to

2000 pF

GND

4

Figure 1. Typical Step-Up Application Circuit 1

CE

1

FB

2

VDD

3

L

22 mH

NCP1403

LX

GND

D MBR0520LT1

5

4

D MBR0520LT1

C

C

R

FB1

R

FB2

C

2

2.2 mF
16 V

ZD

+

V

OUT

C

2

33
mF

+ 0.8

V

OUT

15 V

R

FB1

ǒ

) 1

R

FB2

White LED x 4

Ǔ

Figure 2. Typical Step-Up Application Circuit 2

LX VDD

VLx Limit

PFM ON/OFF
Timing Control

Driver

Soft Start

Comparator

Figure 3. Representative Block Diagram

PFM

CE

UVLO

-

+

Vref

GND

FB

LED

+

0.8V
R

S

I

R

S

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2

NCP1403

PIN FUNCTION DESCRIPTIONS

Pin Symbol Description

1 CE Chip Enable Pin

1. The chip is enabled if a voltage which is equal to or greater than 0.9 V is applied.

2. The chip is disabled if a voltage which is less than 0.3 V is applied.

3. The chip will be enabled if it is left floating.

2 FB PFM comparator inverting input, and is connected to off-chip resistor divider which sets output voltage.

3 VDD Power supply pin for internal circuit.

4 GND Ground pin.

5 LX External inductor connection pin.

MAXIMUM RATINGS

Rating Symbol Value Unit

Power Supply Voltage (Pin 3) V

DD

Input/Output Pin

LX (Pin 5)
LX Peak Sink Current
FB (Pin 2)

V

LX

I

LX

V

FB

CE (Pin 1)

Input Voltage Range
Input Current Range

V

CE

I

CE

Power Dissipation and Thermal Characteristics

Maximum Power Dissipation @ TA = 25°C
Thermal Resistance Junction-to-Air

Operating Ambient Temperature Range T

Operating Junction Temperature Range T

Storage Temperature Range T

P

D

R

q

JA

A

J

stg

Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the
Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect
device reliability.

1. This device series contains ESD protection and exceeds the following tests:
Human Body Model (HBM) "2.0 kV per JEDEC standard: JESD22-A114 for all pins except LX pin.
Human Body Model (HBM) "1.5 kV for LX pin.
Machine Model (MM) "200 V per JEDEC standard: JESD22-A115 for all pins.

2. Latchup Current Maximum Rating: "150 mA per JEDEC standard: JESD78.

3. Moisture Sensitivity Level (MSL): 1 per IPC/JEDEC standard: J-STD-020A.

-0.3 to 6.0 V

-0.3 to 16.0
600

mA

-0.3 to 6.0

-0.3 to 6.0
150

500
250

mA

mW

°C/W

-40 to +85 °C

-40 to +150 °C

-55 to +150 °C

V

V

V

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3

NCP1403

ELECTRICAL CHARACTERISTICS (V

= 15 V, TA =25°C, for min/max values unless otherwise noted.)

OUT

Characteristic Symbol Min Typ Max Unit

ON/OFF TIMING CONTROL

Minimum Off Time (V

= 3.0 V, VFB = 0 V) t

DD

Maximum On Time (Current not asserted) t

Maximum Duty Cycle D

Minimum Startup Voltage (I

= 0 mA) V

OUT

Minimum Startup Voltage Temperature Coefficient (TA = -40 to +85°C) DV

Minimum Supply Voltage (I

= 0 mA) V

OUT

Soft-Start Time t

LX (PIN 5)

Internal Switch Voltage (Note 4) V

LX Pin On-State Sink Current (VLX = 0.4 V, V

Voltage Limit (When VLX reaches V
switch protection circuit)

LXLIM

= 3.0 V) I

DD

, the LX switch is turned off by the LX

Off-State Leakage Current (VLX = 16 V) I

CE (PIN 1)

CE Input Voltage (V

= 3.0 V, VFB = 0 V)

DD

High State, Device Enabled
Low State, Device Enabled

CE Input Current
High State, Device Enabled (V
Low State, Device Enabled (VDD = 5.5 V, VCE = V

= VCE = 5.5 V)

DD

FB

= 0 V)

TOTAL DEVICE

Supply Voltage V

Feedback Voltage V

Feedback Pin Bias Current (VFB = 0.8 V) I

Operating Current 1 (V

FB

Operating Current 2 (VDD = V

Off-state Current (V

= 5.0 V, VCE = 0 V, internal 100 nA pullup current source) I

DD

4. Recommend maximum V

= 0 V, V

OUT

= V

DD

= V

CE

FB

up to 15 V.

= 3.0 V) I

CE

= 3.0 V, Not switching) I

off

on

MAX

start

hold

SS

LX

V

LXLIM

LKG

V

CE(high)

V

CE(low)

I

CE(high)

I

CE(low)

DD

FB

DD1

DD2

OFF

start

LX

FB

0.8 1.3 1.5

4.0 6.0 8.4

75 83 91 %

- 1.3 1.8 V

- 1.6 - mV/°C

- 1.2 1.7 V

0.5 10 - ms

0.5 - 16 V

100 130 - mA

0.55 0.75 1.0 V

- 0.1 1.0

0.9

-

-0.5

-0.5

-

-

0

-0.1

-

0.3

0.5

0.5

1.2 - 5.5 V

0.76 0.8 0.84 V

- 15 30 nA

- 130 200

- 19 25

- 0.3 0.8

ms

ms

mA

V
V

mA
mA

mA

mA

mA

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4

NCP1403

TYPICAL CHARACTERISTICS

17.0

16.5

16.0

15.5

15.0

14.5

, OUTPUT VOLTAGE (V)

14.0

OUT

V

13.5

13.0

14.0

13.5

13.0

12.5

12.0

11.5

, OUTPUT VOLTAGE (V)

11.0

OUT

V

10.5

10.0

15.4

L = 47 mH
V

= 15 V

OUT

C

= 33 mF

OUT

TA = 25°C
Figure 1

1.8 V

2.4 V

3.6 V

4.0 V

3.0 V

I

, OUTPUT CURRENT (mA) I

OUT

Figure 4. Output Voltage versus Output

L = 47 mH
V

OUT

C

OUT

TA = 25°C
Figure 1

1.8 V

= 12 V
= 33 mF

2.4 V

I

OUT

Current (V

, OUTPUT CURRENT (mA)

OUT

3.0 V

= 15 V)

3.6 V

Figure 6. Output Voltage versus Output

Current (V

OUT

= 12 V)

VIN = 5.5

V

5.0 V

706050403020100

VIN = 5.5

V

5.0 V

4.0 V

706050403020100

100

Vin = 5.5 V

80

2.4 V

60

1.8 V

40

EFFICIENCY (%)

20

3.0 V

3.6 V

4.0 V

L = 47 mH
V

OUT

C

OUT

TA = 25°C
Figure 1

5.0 V

= 15 V

= 33 mF

0

80 80

, OUTPUT CURRENT (mA)

OUT

706050403020100

Figure 5. Efficiency versus Output Current

(V

= 15 V)

OUT

100

VIN = 5.5

V

80

60

1.8 V

2.4 V

3.0 V

3.6 V

4.0 V

5.0 V

L = 47 mH
V

= 12 V

EFFICIENCY (%)

40

C

OUT

OUT

= 33 mF
TA = 25°C
Figure 1

20

80

I

, OUTPUT CURRENT (mA)

OUT

706050403020100

Figure 7. Efficiency versus Output Current

(V

= 12 V)

OUT

12.4

80

15.2

I

= 5 mA

15.0

14.8

, OUTPUT VOLTAGE (V)

14.6

OUT

V

OUT

I

OUT

= 0 mA

L = 47 mH
V
C
TA = 25°C
Figure 1

14.4

Vin, INPUT VOLTAGE (V)

Figure 8. Output Voltage versus Input Voltage

(V

= 15 V)

OUT

OUT

OUT

= 15 V

= 33 mF

5.04.54.0

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12.2

I

= 5 mA

I

OUT

OUT

= 0 mA

L = 47 mH
V

= 12 V

OUT

C

= 33 mF

OUT

TA = 25°C
Figure 1

12.0

11.8

, OUTPUT VOLTAGE (V)

11.6

OUT

V

11.4

6.05.53.53.02.52.0

5.04.54.0

6.05.53.53.02.52.0

Vin, INPUT VOLTAGE (V)

Figure 9. Output Voltage versus Input Voltage

(V

= 12 V)

OUT

5

NCP1403

TYPICAL CHARACTERISTICS

1000

V

900

800

700

600

500

OUT

L = 47 mH
D = MBR0520LT1
C

IN

C

OUT

I

OUT

TA = 25°C
Figure 1

400

300

200

, NO LOAD INPUT CURRENT (mA)

100

IN

I

0

VIN, INPUT VOLTAGE (V) VIN, INPUT VOLTAGE (V)

Figure 10. No Load Input Current versus

Input Voltage

6

5

4

3

2

, SWITCH-ON RESISTANCE (W)

DS(on)

1

R

VIN, INPUT VOLTAGE (V) I

Figure 12. Switch-On Resistance versus Input

Voltage

= 15 V

= 10 mF

= 33 mF

= 0 mA

V

= 15 V

OUT

TA = 25°C

600

500

400

300

200

, CURRENT LIMIT (mA)

LIM

I

100

0

654321

5.0

4.5

4.0

3.5

3.0

2.5

2.0

, STARTUP/HOLD VOLTAGE (V)

1.5

HOLD

1.0

/V

0.5

START

654321

V

Figure 13. Startup/Hold Voltage versus Output

TA = 25°C

Figure 11. Current Limit versus Input Voltage

V

= 15 V

OUT

L = 47 mH
C

= 33 mF

OUT

TA = 25°C
Figure 1

V

START

V

HOLD

16141210 2018 28262422

, OUTPUT CURRENT (mA)

OUT

Current

654321

3086420

0.84

0.82

0.80

0.78

, FEEDBACK VOLTAGE (V)

0.76

FB

V

0.74

TA, AMBIENT TEMPERATURE(°C) TA, AMBIENT TEMPERATURE (°C)

Figure 14. Feedback Voltage versus Ambient

Temperature

100

90

80

70

60

, MAXIMUM DUTY CYCLE (%)

MAX

D

50

1007550250-25-50

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6

1007550250-25-50

Figure 15. Maximum Duty Cycle versus

Ambient Temperature

NCP1403

TYPICAL CHARACTERISTICS

9

8

7

6

5

, MAXIMUM SWITCH ON TIME (ms)

on

t

4

TA, AMBIENT TEMPERATURE (°C) TA, AMBIENT TEMPERATURE (°C)

1007550250-25-50

5

4

3

2

1

, MINIMUM SWITCH OFF TIME (ms)

off

t

0

1007550250-25-50

Figure 16. Maximum Switch On Time Figure 17. Minimum Switch Off Time

170

150

130

25

23

21

, OPERATING CURRENT 1 (mA)

DD1

I

OFF-STATE CURRENT (mA)

off,

I

110

0.8

0.6

0.4

0.2

90

70

TA, AMBIENT TEMPERATURE (°C) TA, AMBIENT TEMPERATURE (°C)

Figure 18. Operating Current 1 versus

Ambient Temperature

1

0

TA, AMBIENT TEMPERATURE (°C) TA, AMBIENT TEMPERATURE (°C)

VDD = VCE = 3.0 V

VFB = 0 V

VDD = 5.0 V

VCE = 0 V

19

VDD = VCE = 3.0 V

17

, OPERATING CURRENT 2 (mA)

DD2

I

1007550250-25-50

15

VFB = 3.0 V
NOT SWITCHING

1007550250-25-50

Figure 19. Operating Current 2 versus

Ambient Temperature

25

15

5

-5

-15

, CE HIGH INPUT CURRENT (nA)

-25

CE(high)

1007550250-25-50

I

VDD = 5.5 V

VCE = 5.5 V

1007550250-25-50

Figure 20. Off-State Current versus Ambient

Temperature

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Figure 21. CE High Input Current versus

Ambient Temperature

7

NCP1403

TYPICAL CHARACTERISTICS

L = 47 mH, CIN = 10 mF, C

1. V

= 15 V, 10 V/div

OUT

OUT

= 33 mF, I

2. VLX, 10 V/div

3. VIN = 0 V to 3.6 V, 5 V/div

Figure 22. Startup Waveforms Figure 23. Chip Enable Waveforms

L = 47 mH, CIN = 10 mF, C

1. V

= 15 V (AC Coupled), 100 mV/div

OUT

2. VIN = 3.6 V to 5.5 V, 2.0 V/div

OUT

Figure 24. Line Transient Response Figure 25. Load Transient Response

= 33 mF, I

OUT

OUT

= 20 mA

= 10 mA

L = 47 mH, CIN = 10 mF, C

OUT

mA

1. V

= 15 V, 10 V/div

OUT

2. VLX, 10 V/div

3. VCE = 0 V to 3.3 V, 5 V/div

L = 47 mH, CIN = 10 mF, C

1. V

= 15 V (AC Coupled), 50 mV/div

OUT

2. I

= 1.0 mA to 15 mA, 10 mA/div

OUT

= 33 mF, VIN = 3.6 V, I

= 33 mF, VIN = 3.6 V

OUT

OUT

= 20

L = 47 mH, CIN = 10 mF, C
V, I

= 10 mA

OUT

1. VLX, 5.0 V/div

2. IL, 200 mA/div

3. V

, 50 mV/div

ripple

= 33 mF, VIN = 3.6 V, V

OUT

OUT

= 15

L = 47 mH, CIN = 10 mF, C
V, I

= 30 mA

OUT

1. VLX, 5.0 V/div

2. IL, 200 mA/div

3. V

, 50 mV/div

ripple

= 33 mF, VIN = 3.6 V, V

OUT

OUT

= 15

Figure 26. Operating Waveforms (Medium Load) Figure 27. Operating Waveforms (Heavy Load)

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8

NCP1403

DETAILED OPERATING DESCRIPTION

Operation

The NCP1403 is monolithic DC-DC switching converter
optimized for single Lithium or two cells AA/AAA size
batteries powered portable products.

The NCP1403 device consists of startup circuit, chip
enable circuit, PFM comparator, voltage reference, PFM
on/off timing control circuit, driver, current limit circuit, and
open-drain MOSFET switch. The device operating current
is typically 130 mA, and can be further reduced to about 0.3
mA when the chip is disabled (VCE < 0.3 V).

The operation of NCP1403 can be best understood by
referring to the block diagram and typical application circuit
1 in Figures 3 and 1. The PFM comparator monitors the
output voltage via the external feedback resistor divider by
comparing the feedback voltage with the reference voltage.
When the feedback voltage is lower than the reference
voltage, the PFM control and driver circuit turns on the
N-Channel MOSFET switch and the current ramps up in the
inductor. The switch will remain on for the maximum
on-time, 6.0 ms, or until the current limit is reached,
whichever occurs first. The MOSFET switch is then turned
off and energy stored in the inductor will be discharged to the
output capacitor and load through the Schottky diode. The
MOSFET switch will be turned off for at least the minimum
off-time, 1.3 ms, and will remain off if the feedback voltage
is higher than the reference voltage and output capacitor will
be discharged to sustain the output current, until the
feedback voltage is again lower than reference voltage. This
switching cycle is then repeated to attain voltage regulation.

Soft Start

There is a soft start circuit in NCP1403. When power is
applied to the device, the soft start circuit pumps up the
output voltage to approximately 1.5 V at a fixed duty cycle,
the level at which the converter can operate normally. With
the soft start circuit, the output voltage overshoot is
minimized and the startup capability with heavy loads is also
improved.

ON/OFF Timing Control

The maximum on-time is typically 6.0 ms, whereas, the
minimum off-time is typically 1.3 ms. Owing to the current
limit circuit, the on-time can be shorter. The switching
frequency can be up to 300 kHz.

Voltage Reference and Output Voltage

The internal voltage reference is trimmed to 0.8 V at an
accuracy of ±5.0%. The voltage reference is connected to the
non-inverting input of the PFM comparator and the
inverting input of the PFM comparator is connected to the
FB pin. The output voltage can be set by connected an
external resistor voltage divider from the V

OUT

to the
FB pin. With the internal 16 V MOSFET switch, the output
voltage can be set between VIN to 15 V.

LX Limit

The LX Limit is a current limit feature which is achieved
by monitoring the voltage at the LX pin during the MOSFET
switch turn-on period. When the switch is turned on, current
ramps up in the inductor, and the voltage at the LX pin will
increase according to the Ohm's Law due to the On-state
resistance of the MOSFET. When the VLX is greater than

0.75 V, the switch will be turned off. With the current limit
circuit, saturation of inductor is prevented and output
voltage overshoot during startup can also be minimized.

N-Channel MOSFET Switch

The NCP1403 is built-in with a 16 V open drain
N-Channel MOSFET switch which allows high output
voltage up to 15 V to be generated from simple step-up
topology.

Enable / Disable Operation

The NCP1403 offers IC shut-down mode by the chip
enable pin (CE pin) to reduce current consumption. An
internal 100 nA pullup current source tied the CE pin to
OUT pin by default i.e. user can float the pin CE for
permanent “ON”. When voltage at pin CE is equal to or
greater than 0.9 V, the chip will be enabled, which means the
device is in normal operation. When voltage at pin CE is less
than 0.3 V, the chip is disabled, which means IC is shutdown.
During shutdown, the IC supply current reduces to 0.3 mA
and LX pin enters high impedance state. However, the input
remains connected to the output through the inductor and the
Schottky diode, keeping the output voltage to one diode
forward voltage drop below the input voltage.

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9

NCP1403

APPLICATIONS CIRCUIT INFORMATION

External Component Selection

Inductor

The NCP1403 is designed to work well with a range of
inductance values, the actual inductance value depends on
the specific application, output current, efficiency, and
output ripple voltage. For step up conversion, the device
works well with inductance ranging from 22 mH to 47 mH.
Inductor with small DCR, usually less than 1.0 W, should be
used to minimize loss. It is necessary to choose an inductor
with saturation current greater than the peak switching
current in the application.

If 22 mH inductance is used, lower profile surface mount
inductor can be selected for the same current rating.
Moreover, it permits the converter to switch at higher
frequency up to 300 kHz since the inductor current will ramp
up faster and hit the current limit at a shorter time for smaller
inductance value. However, current output are slightly
lower because the off-time is limited by the minimum
off-time. If 47 mH inductance is selected, higher efficiency
and output current capability are achieved, but the converter
will switch at a lower frequency and the inductor size will be
slightly larger for the same current rating.

For lower inductance value, the inductor current
ramp-down time will be shorter than the minimum off-time.
Consequently, the converter can only operate in
discontinuous conduction mode and lower output current
can be generated. For higher inductance value, if the
inductance is sufficiently large, the maximum on-time will
expire before the current limit is reached. As a result, the
available output power and output current are reduced.
Besides, instability may occur when operation enters CCM.

To ensure the current limit is reached before the maximum
on-time expires, L can be selected according to the
inequality below:

(V

IN *VS

L v

where VS = 0.75 V which is the MOSFET saturation voltage,
and I
Figure 11, and t

is the current limit which can be referred to in

LIM

on(MAX)

If the above condition is satisfied, IPK = I
is the peak inductor current. Then, step-up converter with
inductor satisfy the following condition will operate in
DCM only,

I

LIM @ L

(V

If the IPK = I

) VD* V

OUT

, step-up converter with inductor satisfy

LIM

the following condition will operate in CCM at maximum
output current,

I

LIM @ L

(V

OUT

) VD* V

where VD is the Schottky diode forward voltage drop,
t

off(MIN)

= 1.3 ms.

I

LIM

= 6.0 ms.

)

@ t

IN)

IN)

on(MAX)

v t

off(MIN)

u t

off(MIN)

LIM

; where I

PK

For step-up converter operates in DCM only, the
maximum output current can be calculated from the
equation below:

2

(I

)

L

I

OUT(MAX)

+

2(V

) VD* VIN)

OUT

LIM

ǒ

ǒ

I

LIM

VIN*V

L

S

Ǔ

) t

off(MIN)

For step-up converter operates in CCM, the maximum
output current can be calculated from the equation below:

I

OUT(MAX)

Diode

+ǒI

LIM

*

) VD* VIN) t

OUT

off(MIN)

2L

(V

IN *VS)

Ǔ

@

(V

) VD* VS)

OUT

(V

The diode is the main source of loss in DC-DC converters.
The most importance parameters which affect their
efficiency are the forward voltage drop, VF, and the reverse
recovery time, trr. The forward voltage drop creates a loss
just by having a voltage across the device while a current
flowing through it. The reverse recovery time generates a
loss when the diode is reverse biased, and the current appears
to actually flow backwards through the diode due to the
minority carriers being swept from the P-N junction. A
Schottky diode with the following characteristics is
recommended:

1. Small forward voltage, VF < 0.3 V

2. Small reverse leakage current

3. Fast reverse recovery time / switching speed

4. Rated current larger than peak inductor current,
I

> I

rated

PK

5. Reverse voltage larger than output voltage,
V

Input Capacitor

reverse

> V

OUT

The input capacitor can stabilize the input voltage and
minimize peak current ripple from the source. The value of
the capacitor depends on the impedance of the input source
used. Small ESR (Equivalent Series Resistance) Tantalum
or ceramic capacitor with value of 10 mF should be suitable.

Output Capacitor

The output capacitor is used for sustaining the output
voltage when no current is delivering from the input, and
smoothing the ripple voltage. Low ESR Tantalum capacitor
should be used to reduce output ripple voltage since the
output ripple voltage is dominated by the ESR value of the
Tantalum capacitor. In general, a 22 mF to 47ĂmF low ESR
(0.2 W to 0.4 W) Tantalum capacitor should be appropriate.
The output ripple voltage can be approximately given by the
following equation:

V

Feedback Resistors

ripple

[ (IPK* I

OUT

) @ ESR

Choose the RFB2 value from the range 10 kW to 200 kW
for positive output voltage. The value of R

can then be

FB1

calculated from the equation below:

V

OUT

R

FB1

+ R

FB2

ǒ

0.8

1% tolerance resistors should be used for both R
R

for better V

FB2

OUT

accuracy.

* 1

Ǔ

and

FB1

Ǔ

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10

NCP1403

Output Voltage Higher than 15 V

NCP1403 can be used to generate output voltage higher
than 15 V by adding an external high voltage N-Channel
MOSFET in series with the internal MOSFET switch as
shown in Figure 33. The drain-to-source breakdown
voltage of the external MOSFET must be at least 1V higher
than the output voltage. The diode D1 helps the external
MOSFET to turn off and ensures that most of the voltage
across the external MOSFET during the switch-off period.
Since the high voltage external MOSFET is in series with the
internal MOSFET, higher break down voltage is achieved
but the current capability is not increased.

There is an alternative application circuit shown in Figure
35 which can output voltage up to 30 V. For this circuit, a
diode-capacitor charge-pump voltage doubler constructed
by D2, D3 and C1 is added. During the internal MOSFET
switch-on time, the LX pin is shorted to ground and D2 will
charge up C1 to the stepped up voltage at the cathode of D1.
During the MOSFET switch-off time, the voltage at V

OUT

will be almost equal to the double of the voltage at the
cathode of D1. The V

is monitored by the FB pin via the

OUT

resistor divider and can be set by the resistor values. Since
the maximum voltage at the cathode of D1 is 15V, the
maximum V

is 30 V. The value of C1 can be in the range

OUT

of 0.47 mF to 2.2 mF.

Negative Voltage Generation

The NCP1403 can be used to produce a negative voltage
output by adding a diode-capacitor charge-pump circuit
(D2, D3, and C1) to the LX pin as shown in Figure 32. The
feedback voltage resistor divider is still connected to the
positive output to monitor the positive output voltage and a
small value capacitor is used at C2. When the internal
MOSFET switches off, the voltage at the LX pin charges up
the capacitor through diode D2. When the MOSFET
switches on, the capacitor C1 is effectively connected like a
reversed battery and C1 discharges the stored charges
through the R
charge up C

OUT

of the internal MOSFET and D3 to

ds(on)

and builds up a negative voltage at V

OUT

Since the negative voltage output is not directly monitored
by the NCP1403, the output load regulation of the negative
output is not as good as the standard positive output circuit.
The resistance values of the resistors of the voltage divider
can be one-tenth of those used in the positive output circuit
in order to improve the regulation at light load.

For the application circuit in Figure 36, it is actually the
combination of the application circuits in Figures 32 and 33.

Step-Down Converter

NCP1403 can be configured as a simple step-down
converter by using the open-drain LX pin to drive an
external P-Channel MOSFET as shown in Figure 34. The
resistor RGS is used to switch off the P-Channel MOSFET
during the switch-off period. Too small resistance value
should not be used for RGS, otherwise, the efficiency will be
reduced.

White LED Driver

The NCP1403 can be used as a constant current LED
driver which can drive up to 4 white LEDs in series as shown
in Figure 2. The LED current can be set by the resistance
value of RS. The desired LED current can be calculated by
the equation below:

+

0.8
R

S

I

LED

Moreover, the brightness of the LEDs can be adjusted by
a DC voltage or a PWM signal with an additional circuit
illustrated below:

To FB Pin To LED

DC/PWM
Signal

GND

R2

C1

0.1 mF

D2

R1

100 k

C2

820 pF

With this additional circuit, the maximum LED current is
set by the above equation. The value of R2 can be obtained
by the following equation:

V

* VD* 0.8

R2 +

V

is the maximum voltage of the control signal, V

MAX

is the diode forward voltage, I
LED current and I

MAX

(I

LED(MAX)*ILED(MIN)

ǒ

LED(MIN)

)R

S

R1

LED(MAX)

Ǔ

is the maximum

is the minimum LED current. If
a PWM control signal is used, the signal frequency from 4
kHz to 40 kHz can be applied.

In case the LEDs fail, the feedback voltage will become
zero. The NCP1403 will then switch at maximum duty cycle
and result in a high output voltage which will cause the LX
pin voltage to exceed its maximum rating. A Zener diode can
be added across the output and FB pin to limit the voltage at
the LX pin. The Zener voltage should be higher than the total
forward voltage of the LED string.

.

PCB Layout Hints

The schematic, PCB trace layout, and component
placement of the step-up DC-DC converter demonstration
board are shown in Figure 28 to Figure 31 for PCB layout
design reference.

Grounding

One point grounding should be used for the output power
return ground, the input power return ground, and the device
switch ground to reduce noise. The input ground and output
ground traces must be thick and short enough for current to
flow through. A ground plane should be used to reduce
ground bounce.

R

S

D

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11

NCP1403

Power Signal Traces

Low resistance conducting paths should be used for the
power carrying traces to reduce power loss so as to improve
efficiency (short and thick traces for connecting the inductor
L can also reduce stray inductance). Besides, the length and
area of all the traces with connection to the LX pin should
be minimized. e.g., short and thick traces listed below should
be used in the PCB:

1. Trace from VIN to L

2. Trace from L to LX pin of the IC

3. Trace from L to anode pin of Schottky diode

4. Trace from cathode pin of Schottky diode to
V

.

OUT

TP1

V

IN

1.8 V to 5.0 V

+

C1

10 mF

C3

R1

CE

1

FB

2

External Feedback Resistors

Feedback resistors should be located as close to the FB pin
as possible to minimize noise picked up by the FB pin. The
ground connection of the feedback resistor divider should be
connected directly to the GND pin.

Input Capacitor

The input capacitor should be located close to both the V
to the inductor and the VDD pin of the IC.

Output Capacitor

The output capacitor should be placed close to the output
terminals to obtain better smoothing effect on output ripple
voltage.

L1

47 mH

LX

5

NCP1403

D1

MBR0520LT1

+

C2

33 mF

TP3
V

OUT

15 V

IN

TP2

GND

Enable

R2

VDD

3

GND

4

Figure 28. Step-Up Converter Demonstration Board Schematic

TP4
GND

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12

NCP1403

Figure 29. Step-Up Converter Demonstration Board Top Layer Copper

Figure 30. Step-Up Converter Demonstration Board Bottom Layer Copper

Figure 31. Step-Up Converter Demonstration Board Top Layer Component Silkscreen

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13

NCP1403

Components Supplier

Parts Supplier Part Number Description Phone

L1 Sumida Electric Co. Ltd. CD43-470KC

D1 ON Semiconductor MBR0520LT1 Schottky Power Rectifier (852) 2689-0088

C1 Kemet Electronics Corp. T494A106K010AS

C2 Kemet Electronics Corp. T494C336K016AS

Low ESR Tantalum Capacitor 10 mF/10 V

Low ESR Tantalum Capacitor 33 mF/16 V

Inductor 47 mH

OTHER APPLICATIONS

L

V

IN

2.0 V to 5.5 V

C1

10 mF

L: CD43-470KC, Sumida
C1: T494A106K010AS, Kemet
C2: EMK107BJ104MA, Taiyo Yuden
C3: GMK316F225ZG, Taiyo Yuden
C4: T494D336K025AS, Kemet
D1, D2, D3: MBR0520LT1, ON Semiconductor

+

CE

VDD

1

FB

2

3

47 mH

NCP1403

LX

5

GND

6

D1

MBR0520LT1

C

C

3000 pF

C3

2.2 mF

MBR0520LT1 x 2

D3

D2

C2

0.1 mF

R

FB1

R

FB2

V

OUT

+

C4

33 mF

25 V

[*0.8

(852) 2880-6688

(852) 2305-1168

(852) 2305-1168

V

OUT

-15 V
6 mA at VIN = 2.0 V
40 mA at VIN = 5.5 V

R

FB1

ǒ

) 1Ǔ) 1

R

FB2

Figure 32. Positive-to-Negative Output Converter for Negative LCD Bias

V

IN

3.0 V to 5.5 V

C1

10 mF

10 V

L: CD43-470KC, Sumida
C1: T494A106K010AS, Kemet
C2: T494D226K035AS, Kemet
Q1: MGSF1N03T1, ON Semiconductor

NTHS5402T1, ON Semiconductor
D1: MBR0530T1, ON Semiconductor
D2: MMSD914T1, ON Semiconductor

+

CE

1

FB

2

VDD

3

L

47 mH

NCP1403

MGSF1N03T1

/

NTHS5402T1

LX

5

D2 MMSD914T1

GND

6

D1

Q1

750 pF to

2000 pF

MBR0530T1

C

C

R

R

V

FB1

FB2

OUT

V

OUT

Up to 29 V

+

6 mA at VIN = 3.0 V

C2

35 mA at VIN = 5.5 V

22 mF

35 V

R

FB1

ǒ

+ 0.8

R

FB2

) 1

Ǔ

Figure 33. Step-Up DC-DC Converter with 29 V Output Voltage

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14

NCP1403

V

IN

2.2 V to 4.2 V

C1

22 mF

10 V

L: CD43-101KC, Sumida
C1: T494C226K010AS, Kemet
C2: T494D686K006AS, Kemet
Q1: MGSF1P02ELT1, ON Semiconductor
D1: MBR0520LT1, ON Semiconductor

+

CE

FB

VDD

Figure 34. Step-down DC-DC Converter with 1.6 V Output Voltage for DSP Circuit

1

2

3

NCP1403

LX

5

GND

6

Q1

R

820

GS

MBR0520LT1

MGSF1P02LT1

D1

L 100

mH

C

C

750 pF to

2000 pF

V

68 mF

R

FB1

R

FB2

OUT

6 V

+ 0.8

+

C2

ǒ

R
R

V

OUT

1.6 V
200 mA
at VIN =

2.2 V

FB1

) 1

FB2

Ǔ

V

IN

1.8 V to 5.5 V

+

C1

10 mF

10 V

R

C

FB1

C

750 pF to

2000 pF

R

FB2

L: CD43-470KC, Sumida
C1: T494A106K010AS, Kemet
C2, C4: T494D106K020AS, Kemet
C3: GMK316F225ZG, Taiyo Yuden
D1, D2, D3: MBR0520LT1, ON Semiconductor

CE

1

FB

2

VDD

3

Figure 35. Step-Up DC-DC Converter with 30 V Output Voltage

L

47 mH

U1

NCP1403

LX

5

GND

6

C3

D1

2.2 mF

D3

D2
MBR0520LT1

MBR0520LT1

MBR0520LT1

V

OUT

30 V

+

2 mA at VIN = 1.8 V

C4

35 mA at VIN = 5.5 V

10 mF

20 V

+

C2

10 mF

20 V

V

+ 0.8

OUT

R

FB1

ǒ

R

FB2

) 1

Ǔ

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15

V

IN

3.5 V to 5.0 V

+

C1

10 mF

10 V

R

C

FB1

C

750 pF to

2000 pF

R

FB2

L: CD43-470KC, Sumida
C1: T494A106K010AS, Kemet
C2: UMK212F105ZG, Taiyo Yuden
C3: GMK316F225ZG, Taiyo Yuden
C4: T494D226K035AS, Kemet
Q1: MGSF1N03T1, ON Semiconductor/

NTHS5402T1, ON Semiconductor
D1, D2: MMSD914T1, ON Semiconductor
D3, D4: MBR0530T1, ON Semiconductor

CE

1

FB

2

VDD

3

Figure 36. Voltage Inverting DC-DC Converter with -28 V Output Voltage

L

47 mH

U1

NCP1403

NCP1403

D3

C3

2.2 mF / 50 V

LX

5

MMSD914T1

D1

GND

6

MBR0530T1 x 2

D4

D2

MMSD914T1

Q1
MGSF1N03T1
/
NTHS5402T1

V

[*0.8

OUT

ǒ

R
R

+

+

FB1
FB2

C4

22 mF

35 V

C2

1 mF
50 V

) 1Ǔ) 1

V

OUT

-28 V

9 mA at VIN = 3.3 V
20 mA at VIN = 5.0 V

VIN 1.8 V to 5.5 V

C1

10 mF

L1: CD43-470KC, Sumida
C1: T494A106K010AS, Kemet
C2, C5: T494C226K020AS, Kemet
C3: UMK107B102KZ, Taiyo Yuden
C4: TMK316BJ225ML, Taiyo Yuden
D1, D2, D3: MBR0520LT1, ON Semiconductor
R1: 390 kW
R2: 22 kW

10 V

ON

JPI

OFF

750 pF to

2000 pF

C3

CE

1

R1

FB

2

R2

VDD

3

Figure 37. +15 V, -15 V Outputs Converter for LCD Bias Supply

L1

47 mH

U1

NCP1403

LX

5

GND

6

MBR0520LT1

D2

C4

2.2 mF

V

+ 0.8

OUT1

V

[*V

OUT2

MBR0520LT1

D3

D1
MBR0520LT1

R

FB1

ǒ

R

FB2

OUT1

) 1

) 0.3

V

OUT2

-15 V

C5

+

22 mF

C2

+

22 mF
20 V

2 mA at VIN = 1.8 V
5 mA at VIN = 2.4 V

20 V

10 mA at VIN = 3.0 V

V

OUT1

15 V

2 mA at VIN = 1.8 V
5 mA at VIN = 2.4 V
10 mA at VIN = 3.0 V

Ǔ

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16

NCP1403

L1

VIN 1.8 V to 5.5 V

C1

+

10 mF

L1: CD43-470KC, Sumida
C1, C2: T494A106K010AS, Kemet
C3: UMK107B102KZ, Taiyo Yuden
C4, C5: TMK316BJ225ML, Taiyo Yuden
C6, C7: T494C226K020AS, Kemet
D1, D2, D3, D4, D5: MBR0520LT1, ON Semiconductor
R1: 390 kW
R2: 22 kW

10 V

ON

JPI

OFF

750 pF to

2000 pF

C3

CE

1

R1

FB

2

R2

VDD

3

Figure 38. +15 V, -7.5 V Outputs Converter for CCD Supply Circuit

47 mH

U1

NCP1403

LX

5

GND

6

MBR0520LT1

D3

C5

2.2 mF

MBR0520LT1

D1

MBR0520LT1

V

+ 0.8

OUT1

V

[*

OUT2

D4

MBR0520LT1

C4

2.2 mF

D2

R

FB1

ǒ

R

FB2

V

OUT1

2

MBR0520LT1

D5

+

C2

10 mF
10 V

Ǔ

) 1

V

OUT2

-7.5 V

C7

+

22 mF

C6

+

22 mF
20 V

5 mA at V

20 V

V

OUT1

15 V
20 mA at VIN = 3.0 V

= 3.0 V

IN

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17

NCP1403

PACKAGE DIMENSIONS

TSOP-5

SN SUFFIX

CASE 483-02

ISSUE G

NOTES:

1. DIMENSIONING AND TOLERANCING PER

NOTE 5

2X

2X

T0.10

T0.20

54

123

L

G

D

0.205XC AB

M

S

B

K

DETAIL Z

A

J

DETAIL Z

C

0.05

H

SEATING
PLANE

T

SOLDERING FOOTPRINT*

1.9

0.95

0.037

0.074

ASME Y14.5M, 1994.

2. CONTROLLING DIMENSION: MILLIMETERS.

3. MAXIMUM LEAD THICKNESS INCLUDES
LEAD FINISH THICKNESS. MINIMUM LEAD
THICKNESS IS THE MINIMUM THICKNESS
OF BASE MATERIAL.

4. DIMENSIONS A AND B DO NOT INCLUDE
MOLD FLASH, PROTRUSIONS, OR GATE
BURRS.

5. OPTIONAL CONSTRUCTION: AN
ADDITIONAL TRIMMED LEAD IS ALLOWED
IN THIS LOCATION. TRIMMED LEAD NOT TO
EXTEND MORE THAN 0.2 FROM BODY.

MILLIMETERS

DIM MIN MAX

A 3.00 BSC
B 1.50 BSC
C 0.90 1.10
D 0.25 0.50
G 0.95 BSC
H 0.01 0.10

J 0.10 0.26
K 0.20 0.60
L 1.25 1.55
M 0 10

__

S 2.50 3.00

2.4

0.094

1.0

0.039

0.7

0.028

SCALE 10:1

ǒ

inches

mm

Ǔ

*For additional information on our Pb-Free strategy and soldering

details, please download the ON Semiconductor Soldering and
Mounting Techniques Reference Manual, SOLDERRM/D.

The product described herein (NCP1403), may be covered by the following U.S. patents: 6,518,834. There may be other patents pending.

ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice
to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability
arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages.
“Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All
operating parameters, including “Typicals” must be validated for each customer application by customer's technical experts. SCILLC does not convey any license under its patent rights
nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications
intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should
Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates,
and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death
associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal
Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner.

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For additional information, please contact your local
Sales Representative

NCP1403/D

18