© Semiconductor Components Industries, LLC, 2007
May, 2007 - Rev. 6
1Publication Order Number:
NCP1403/D
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 VOUT = 15 V, IOUT = 50 mA, VIN = 5.0 V
•78% Efficiency at VOUT = 15 V, IOUT = 30 mA, VIN = 3.6 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
Typical Applications
•LCD Bias
•Personal Digital Assistants (PDA)
•Digital Still Camera
•Handheld Games
•Hand-held Instrument
TSOP-5
SN SUFFIX
CASE 483
MARKING DIAGRAM AND
PIN CONNECTIONS
1
3GND
CE
2
FB
VDD 4
LX
5
(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)
1
5
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DCEAYWG
G
Device Package Shipping†
ORDERING INFORMATION
NCP1403SNT1 TSOP-5 3000/Tape & Reel
†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.
NCP1403SNT1G TSOP-5
(Pb-Free)
3000/Tape & Reel
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Figure 1. Typical Step-Up Application Circuit 1
NCP1403
GND
4
LX
5
VDD
3
FB
2
CE
1
+
Enable
VIN
1.8 V to 5.5 V
C1
10 mF
L47 mHD MBR0520LT1
750 pF to
2000 pF CC
RFB1
RFB2
+C2
33
mF
VOUT
15 V
VOUT +0.8ǒRFB1
RFB2 )1Ǔ
Figure 2. Typical Step-Up Application Circuit 2
NCP1403
GND
4
LX
5
VDD
3
FB
2
CE
1
Enable
VIN
2.7 V to 5.5 V
C1
4.7 mF
10 V
L22 mHD MBR0520LT1
C2
2.2 mF
16 V
ILED +0.8V
RS
White LED x 4
RS
ZD
Figure 3. Representative Block Diagram
+
-
PFM
Comparator
PFM ON/OFF
Timing Control
VLx Limit UVLO
Soft Start
Vref
LX VDD
CE GND
FB
Driver
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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) VDD -0.3 to 6.0 V
Input/Output Pin
LX (Pin 5)
LX Peak Sink Current
FB (Pin 2)
VLX
ILX
VFB
-0.3 to 16.0
600
-0.3 to 6.0
V
mA
V
CE (Pin 1)
Input Voltage Range
Input Current Range
VCE
ICE
-0.3 to 6.0
150
V
mA
Power Dissipation and Thermal Characteristics
Maximum Power Dissipation @ TA = 25°C
Thermal Resistance Junction-to-Air
PD
RqJA
500
250
mW
°C/W
Operating Ambient Temperature Range TA-40 to +85 °C
Operating Junction Temperature Range TJ-40 to +150 °C
Storage Temperature Range Tstg -55 to +150 °C
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.
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ELECTRICAL CHARACTERISTICS (VOUT = 15 V, TA =25°C, for min/max values unless otherwise noted.)
Characteristic Symbol Min Typ Max Unit
ON/OFF TIMING CONTROL
Minimum Off Time (VDD = 3.0 V, VFB = 0 V) toff 0.8 1.3 1.5 ms
Maximum On Time (Current not asserted) ton 4.0 6.0 8.4 ms
Maximum Duty Cycle DMAX 75 83 91 %
Minimum Startup Voltage (IOUT = 0 mA) Vstart - 1.3 1.8 V
Minimum Startup Voltage Temperature Coefficient (TA = -40 to +85°C) DVstart - 1.6 - mV/°C
Minimum Supply Voltage (IOUT = 0 mA) Vhold - 1.2 1.7 V
Soft-Start Time tSS 0.5 10 - ms
LX (PIN 5)
Internal Switch Voltage (Note 4) VLX 0.5 - 16 V
LX Pin On-State Sink Current (VLX = 0.4 V, VDD = 3.0 V) ILX 100 130 - mA
Voltage Limit (When VLX reaches VLXLIM, the LX switch is turned off by the LX
switch protection circuit)
VLXLIM 0.55 0.75 1.0 V
Off-State Leakage Current (VLX = 16 V) ILKG - 0.1 1.0 mA
CE (PIN 1)
CE Input Voltage (VDD = 3.0 V, VFB = 0 V)
High State, Device Enabled
Low State, Device Enabled
VCE(high)
VCE(low)
0.9
-
-
-
-
0.3
V
V
CE Input Current
High State, Device Enabled (VDD = VCE = 5.5 V)
Low State, Device Enabled (VDD = 5.5 V, VCE = VFB = 0 V)
ICE(high)
ICE(low)
-0.5
-0.5
0
-0.1
0.5
0.5
mA
mA
TOTAL DEVICE
Supply Voltage VDD 1.2 - 5.5 V
Feedback Voltage VFB 0.76 0.8 0.84 V
Feedback Pin Bias Current (VFB = 0.8 V) IFB - 15 30 nA
Operating Current 1 (VFB = 0 V, VDD = VCE = 3.0 V) IDD1 - 130 200 mA
Operating Current 2 (VDD = VCE = VFB = 3.0 V, Not switching) IDD2 - 19 25 mA
Off-state Current (VDD = 5.0 V, VCE = 0 V, internal 100 nA pullup current source) IOFF - 0.3 0.8 mA
4. Recommend maximum VOUT up to 15 V.
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TYPICAL CHARACTERISTICS
Figure 4. Output Voltage versus Output
Current (VOUT = 15 V)
Figure 5. Efficiency versus Output Current
(VOUT = 15 V)
IOUT
, OUTPUT CURRENT (mA) IOUT
, OUTPUT CURRENT (mA)
706050403020100
13.0
13.5
14.0
14.5
15.0
15.5
16.0
17.0
706050403020100
0
20
40
60
100
Figure 6. Output Voltage versus Output
Current (VOUT = 12 V)
Figure 7. Efficiency versus Output Current
(VOUT = 12 V)
Figure 8. Output Voltage versus Input Voltage
(VOUT = 15 V)
Figure 9. Output Voltage versus Input Voltage
(VOUT = 12 V)
Vin, INPUT VOLTAGE (V)
6.05.53.53.02.52.0
14.4
14.6
14.8
15.0
15.4
VOUT
, OUTPUT VOLTAGE (V)
80 80
80
EFFICIENCY (%)
15.2
VOUT
, OUTPUT VOLTAGE (V)
16.5
L = 47 mH
VOUT = 15 V
COUT = 33 mF
TA = 25°C
Figure 1
L = 47 mH
VOUT = 15 V
COUT = 33 mF
TA = 25°C
Figure 1
VIN = 5.5
V
5.0 V
4.0 V
3.6 V
3.0 V
2.4 V
1.8 V
Vin = 5.5 V
5.0 V
4.0 V
3.6 V
3.0 V
2.4 V
1.8 V
5.04.54.0
L = 47 mH
VOUT = 15 V
COUT = 33 mF
TA = 25°C
Figure 1
IOUT = 5 mA
IOUT = 0 mA
Vin, INPUT VOLTAGE (V)
6.05.53.53.02.52.0
11.4
11.6
11.8
12.0
12.4
12.2
VOUT
, OUTPUT VOLTAGE (V)
5.04.54.0
L = 47 mH
VOUT = 12 V
COUT = 33 mF
TA = 25°C
Figure 1
IOUT = 5 mA
IOUT = 0 mA
IOUT
, OUTPUT CURRENT (mA)
706050403020100
20
40
60
100
80
80
EFFICIENCY (%)
L = 47 mH
VOUT = 12 V
COUT = 33 mF
TA = 25°C
Figure 1
VIN = 5.5
V5.0 V
4.0 V
3.6 V
3.0 V
2.4 V
1.8 V
IOUT
, OUTPUT CURRENT (mA)
706050403020100
10.0
10.5
11.0
11.5
12.0
12.5
13.0
14.0
VOUT
, OUTPUT VOLTAGE (V)
80
13.5 L = 47 mH
VOUT = 12 V
COUT = 33 mF
TA = 25°C
Figure 1 VIN = 5.5
V
5.0 V
4.0 V
3.6 V
3.0 V
2.4 V
1.8 V
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TYPICAL CHARACTERISTICS
Figure 10. No Load Input Current versus
Input Voltage
Figure 11. Current Limit versus Input Voltage
VIN, INPUT VOLTAGE (V) VIN, INPUT VOLTAGE (V)
654321
0
100
200
300
400
500
654321
0
100
200
300
600
Figure 12. Switch-On Resistance versus Input
Voltage
Figure 13. Startup/Hold Voltage versus Output
Current
VIN, INPUT VOLTAGE (V) IOUT
, OUTPUT CURRENT (mA)
654321
2
3
4
6
3086420
0.5
1.0
1.5
4.0
4.5
5.0
Figure 14. Feedback Voltage versus Ambient
Temperature
Figure 15. Maximum Duty Cycle versus
Ambient Temperature
TA, AMBIENT TEMPERATURE(°C) TA, AMBIENT TEMPERATURE (°C)
1007550250-25-50
0.74
0.76
0.78
0.80
0.84
1007550250-25-50
50
60
70
80
90
100
IIN, NO LOAD INPUT CURRENT (mA)
500
ILIM, CURRENT LIMIT (mA)
RDS(on), SWITCH-ON RESISTANCE (W)
VSTART/VHOLD, STARTUP/HOLD VOLTAGE (V)
0.82
VFB, FEEDBACK VOLTAGE (V)
DMAX, MAXIMUM DUTY CYCLE (%)
5
600
700
800
900
1000
VOUT = 15 V
L = 47 mH
D = MBR0520LT1
CIN = 10 mF
COUT = 33 mF
IOUT = 0 mA
TA = 25°C
Figure 1
TA = 25°C
400
1
VOUT = 15 V
TA = 25°C
16141210 2018 28262422
2.5
3.0
3.5
2.0
VOUT = 15 V
L = 47 mH
COUT = 33 mF
TA = 25°C
Figure 1 VSTART
VHOLD
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TYPICAL CHARACTERISTICS
Figure 16. Maximum Switch On Time Figure 17. Minimum Switch Off Time
TA, AMBIENT TEMPERATURE (°C) TA, AMBIENT TEMPERATURE (°C)
1007550250-25-50
4
5
6
7
8
9
1007550250-25-50
0
1
2
3
5
Figure 18. Operating Current 1 versus
Ambient Temperature
Figure 19. Operating Current 2 versus
Ambient Temperature
Figure 20. Off-State Current versus Ambient
Temperature
Figure 21. CE High Input Current versus
Ambient Temperature
ton, MAXIMUM SWITCH ON TIME (ms)
4
toff, MINIMUM SWITCH OFF TIME (ms)
TA, AMBIENT TEMPERATURE (°C) TA, AMBIENT TEMPERATURE (°C)
1007550250-25-50
70
90
110
130
150
170
1007550250-25-50
15
17
19
21
25
IDD1, OPERATING CURRENT 1 (mA)
23
IDD2, OPERATING CURRENT 2 (mA)
TA, AMBIENT TEMPERATURE (°C) TA, AMBIENT TEMPERATURE (°C)
1007550250-25-50
0
0.2
0.4
0.6
0.8
1
1007550250-25-50
-25
-15
-5
5
25
Ioff, OFF-STATE CURRENT (mA)
15
ICE(high), CE HIGH INPUT CURRENT (nA)
VDD = VCE = 3.0 V
VFB = 0 V
VDD = VCE = 3.0 V
VFB = 3.0 V
NOT SWITCHING
VDD = 5.0 V
VCE = 0 V
VDD = 5.5 V
VCE = 5.5 V
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Figure 22. Startup Waveforms Figure 23. Chip Enable Waveforms
Figure 24. Line Transient Response Figure 25. Load Transient Response
Figure 26. Operating Waveforms (Medium Load) Figure 27. Operating Waveforms (Heavy Load)
L = 47 mH, CIN = 10 mF, COUT = 33 mF, VIN = 3.6 V, IOUT = 20
mA
1. VOUT = 15 V, 10 V/div
2. VLX, 10 V/div
3. VCE = 0 V to 3.3 V, 5 V/div
L = 47 mH, CIN = 10 mF, COUT = 33 mF, IOUT = 20 mA
1. VOUT = 15 V, 10 V/div
2. VLX, 10 V/div
3. VIN = 0 V to 3.6 V, 5 V/div
L = 47 mH, CIN = 10 mF, COUT = 33 mF, IOUT = 10 mA
1. VOUT = 15 V (AC Coupled), 100 mV/div
2. VIN = 3.6 V to 5.5 V, 2.0 V/div
L = 47 mH, CIN = 10 mF, COUT = 33 mF, VIN = 3.6 V
1. VOUT = 15 V (AC Coupled), 50 mV/div
2. IOUT = 1.0 mA to 15 mA, 10 mA/div
L = 47 mH, CIN = 10 mF, COUT = 33 mF, VIN = 3.6 V, VOUT = 15
V, IOUT = 10 mA
1. VLX, 5.0 V/div
2. IL, 200 mA/div
3. Vripple, 50 mV/div
L = 47 mH, CIN = 10 mF, COUT = 33 mF, VIN = 3.6 V, VOUT = 15
V, IOUT = 30 mA
1. VLX, 5.0 V/div
2. IL, 200 mA/div
3. Vripple, 50 mV/div
TYPICAL CHARACTERISTICS
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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 VOUT 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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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:
Lv(VIN *VS)
ILIM @ton(MAX)
where VS = 0.75 V which is the MOSFET saturation voltage,
and ILIM is the current limit which can be referred to in
Figure 11, and ton(MAX) = 6.0 ms.
If the above condition is satisfied, IPK = ILIM; where IPK
is the peak inductor current. Then, step-up converter with
inductor satisfy the following condition will operate in
DCM only,
ILIM @L
(VOUT )VD*VIN) vtoff(MIN)
If the IPK = ILIM, step-up converter with inductor satisfy
the following condition will operate in CCM at maximum
output current,
ILIM @L
(VOUT )VD*VIN) utoff(MIN)
where VD is the Schottky diode forward voltage drop,
toff(MIN) = 1.3 ms.
For step-up converter operates in DCM only, the
maximum output current can be calculated from the
equation below:
IOUT(MAX) +(ILIM)2L
2(VOUT )VD*VIN)ǒǒILIM L
VIN*VSǓ)toff(MIN)Ǔ
For step-up converter operates in CCM, the maximum
output current can be calculated from the equation below:
IOUT(MAX) +ǒILIM *
(VOUT )VD*VIN) toff(MIN)
2L Ǔ@
(VIN *VS)
(VOUT )VD*VS)
Diode
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,
Irated > IPK
5. Reverse voltage larger than output voltage,
Vreverse > VOUT
Input Capacitor
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:
Vripple [(IPK *IOUT)@ESR
Feedback Resistors
Choose the RFB2 value from the range 10 kW to 200 kW
for positive output voltage. The value of RFB1 can then be
calculated from the equation below:
RFB1 +RFB2ǒVOUT
0.8 *1Ǔ
1% tolerance resistors should be used for both RFB1 and
RFB2 for better VOUT accuracy.
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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 VOUT
will be almost equal to the double of the voltage at the
cathode of D1. The VOUT is monitored by the FB pin via the
resistor divider and can be set by the resistor values. Since
the maximum voltage at the cathode of D1 is 15V, the
maximum VOUT is 30 V. The value of C1 can be in the range
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 Rds(on) of the internal MOSFET and D3 to
charge up COUT and builds up a negative voltage at VOUT.
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:
ILED +0.8
RS
Moreover, the brightness of the LEDs can be adjusted by
a DC voltage or a PWM signal with an additional circuit
illustrated below:
R2
D2
C1
0.1 mF
820 pF
C2
100 k
R1
RS
GND
DC/PWM
Signal
To FB Pin To LED
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:
R2 +VMAX *VD*0.8
ǒ(ILED(MAX)*ILED(MIN))RS
R1 Ǔ
VMAX is the maximum voltage of the control signal, VD
is the diode forward voltage, ILED(MAX) is the maximum
LED current and ILED(MIN) 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.
NCP1403
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12
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
VOUT.
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 VIN
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.
Figure 28. Step-Up Converter Demonstration Board Schematic
NCP1403
GND
4
LX
5
VDD
3
FB
2
CE
1
TP1
VIN
1.8 V to 5.0 V
C1
10 mF
L1 47 mH
C3
R1
R2
+
C2
33 mF
TP3
VOUT
15 V
D1
MBR0520LT1
TP4
GND
+
Enable
TP2
GND
NCP1403
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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
NCP1403
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14
Components Supplier
Parts Supplier Part Number Description Phone
L1 Sumida Electric Co. Ltd. CD43-470KC Inductor 47 mH(852) 2880-6688
D1 ON Semiconductor MBR0520LT1 Schottky Power Rectifier (852) 2689-0088
C1 Kemet Electronics Corp. T494A106K010AS Low ESR Tantalum Capacitor 10 mF/10 V (852) 2305-1168
C2 Kemet Electronics Corp. T494C336K016AS Low ESR Tantalum Capacitor 33 mF/16 V (852) 2305-1168
OTHER APPLICATIONS
Figure 32. Positive-to-Negative Output Converter for Negative LCD Bias
NCP1403
GND
6
LX
5
VDD
3
FB
2
CE
1
+
VIN
2.0 V to 5.5 V
C1
10 mF
L47 mHMBR0520LT1 x 2
3000 pF
RFB1
RFB2
+C4
VOUT
-15 V
VOUT [*0.8ǒRFB1
RFB2 )1Ǔ)1
0.1 mF
C3 2.2 mF
D1
MBR0520LT1 D2
D3
33 mF
25 V
C2
6 mA at VIN = 2.0 V
40 mA at VIN = 5.5 V
CC
L: CD43-470KC, Sumida
C1: T494A106K010AS, Kemet
C2: EMK107BJ104MA, Taiyo Yuden
C3: GMK316F225ZG, Taiyo Yuden
C4: T494D336K025AS, Kemet
D1, D2, D3: MBR0520LT1, ON Semiconductor
Figure 33. Step-Up DC-DC Converter with 29 V Output Voltage
NCP1403
GND
6
LX
5
VDD
3
FB
2
CE
1
+
VIN
3.0 V to 5.5 V
C1
10 mF
10 V
L47 mHMBR0530T1
CC
RFB1
RFB2
+
C2
VOUT
VOUT +0.8ǒRFB1
RFB2 )1Ǔ
D1
D2 MMSD914T1
22 mF
35 V
NTHS5402T1
Q1
750 pF to
2000 pF
Up to 29 V
MGSF1N03T1
/
6 mA at VIN = 3.0 V
35 mA at VIN = 5.5 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
NCP1403
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Figure 34. Step-down DC-DC Converter with 1.6 V Output Voltage for DSP Circuit
NCP1403
GND
6
LX
5
VDD
3
FB
2
CE
1
+
VIN
2.2 V to 4.2 V
C1
22 mF
10 V
L 100
mH
MGSF1P02LT1
CC
RFB1
RFB2
+
C2
VOUT
VOUT +0.8ǒRFB1
RFB2 )1Ǔ
Q1
68 mF
6 V
D1 750 pF to
2000 pF
1.6 V
MBR0520LT1
RGS
820
L: CD43-101KC, Sumida
C1: T494C226K010AS, Kemet
C2: T494D686K006AS, Kemet
Q1: MGSF1P02ELT1, ON Semiconductor
D1: MBR0520LT1, ON Semiconductor
200 mA
at VIN =
2.2 V
Figure 35. Step-Up DC-DC Converter with 30 V Output Voltage
NCP1403
GND
6
LX
5
VDD
3
FB
2
CE
1
VIN
1.8 V to 5.5 V
C1
10 mF
10 V
L47 mHMBR0520LT1
CCRFB1
RFB2
+C4
VOUT
VOUT +0.8ǒRFB1
RFB2 )1Ǔ
D3
10 mF
20 V
D1
750 pF to
2000 pF
30 V
MBR0520LT1
U1
C3 2.2 mF
D2
MBR0520LT1
+C2
10 mF
20 V
+
L: CD43-470KC, Sumida
C1: T494A106K010AS, Kemet
C2, C4: T494D106K020AS, Kemet
C3: GMK316F225ZG, Taiyo Yuden
D1, D2, D3: MBR0520LT1, ON Semiconductor
2 mA at VIN = 1.8 V
35 mA at VIN = 5.5 V
NCP1403
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Figure 36. Voltage Inverting DC-DC Converter with -28 V Output Voltage
NCP1403
GND
6
LX
5
VDD
3
FB
2
CE
1
VIN
3.5 V to 5.0 V
C1
10 mF
10 V
L47 mH
CCRFB1
RFB2
VOUT [*0.8ǒRFB1
RFB2 )1Ǔ)1
750 pF to
2000 pF
U1
MBR0530T1 x 2
VOUT
D4
MMSD914T1
Q1
D1
MMSD914T1 C2
1 mF
50 V
2.2 mF / 50 V
C3 D2
D3
C4
22 mF
35 V
+
+
-28 V
MGSF1N03T1
/
NTHS5402T1
9 mA at VIN = 3.3 V
20 mA at VIN = 5.0 V
+
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
Figure 37. +15 V, -15 V Outputs Converter for LCD Bias Supply
NCP1403
GND
6
LX
5
VDD
3
FB
2
CE
1
VIN 1.8 V to 5.5 V
10 mF
10 V
L1 47 mH
C3 R1
R2
VOUT1 +0.8ǒRFB1
RFB2 )1Ǔ
750 pF to
2000 pF
U1
MBR0520LT1
VOUT2
D3
MBR0520LT1
D1 C2
22 mF
20 V
2.2 mF
C4
D2
C5
22 mF
20 V
+
+
-15 V
2 mA at VIN = 1.8 V
5 mA at VIN = 2.4 V
10 mA at VIN = 3.0 V
ON
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
VOUT2 [*VOUT1 )0.3
MBR0520LT1
JPI
OFF
VOUT1
15 V
2 mA at VIN = 1.8 V
5 mA at VIN = 2.4 V
10 mA at VIN = 3.0 V
C1
NCP1403
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Figure 38. +15 V, -7.5 V Outputs Converter for CCD Supply Circuit
NCP1403
GND
6
LX
5
VDD
3
FB
2
CE
1
VIN 1.8 V to 5.5 V
10 mF
10 V
L1 47 mH
C3 R1
R2
VOUT1 +0.8ǒRFB1
RFB2 )1Ǔ
750 pF to
2000 pF
U1
MBR0520LT1
VOUT2
D4
MBR0520LT1
D2 C6
22 mF
20 V
2.2 mF
C5
D3
C7
22 mF
20 V
+
+
-7.5 V
5 mA at VIN = 3.0 V
ON
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
VOUT2 [*VOUT1
2
MBR0520LT1
JPI
OFF
VOUT1
15 V
20 mA at VIN = 3.0 V
+
C1
+
C4 2.2 mF
C2
10 mF
10 V
MBR0520LT1
D1
MBR0520LT1
D5
NCP1403
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PACKAGE DIMENSIONS
TSOP-5
SN SUFFIX
CASE 483-02
ISSUE G
NOTES:
1. DIMENSIONING AND TOLERANCING PER
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.
DIM MIN MAX
MILLIMETERS
A3.00 BSC
B1.50 BSC
C0.90 1.10
D0.25 0.50
G0.95 BSC
H0.01 0.10
J0.10 0.26
K0.20 0.60
L1.25 1.55
M0 10
S2.50 3.00
123
54 S
A
G
L
B
D
H
C
J
__
0.7
0.028
1.0
0.039
ǒmm
inchesǓ
SCALE 10:1
0.95
0.037
2.4
0.094
1.9
0.074
*For additional information on our Pb-Free strategy and soldering
details, please download the ON Semiconductor Soldering and
Mounting Techniques Reference Manual, SOLDERRM/D.
SOLDERING FOOTPRINT*
0.20
5X
CAB
T0.10
2X
2X T0.20
NOTE 5
T
SEATING
PLANE
0.05
K
M
DETAIL Z
DETAIL Z
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.
NCP1403/D
The product described herein (NCP1403), may be covered by the following U.S. patents: 6,518,834. There may be other patents pending.
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