CD54-470L (ON)
200 mA/ PFM Step-Up Micropower Switching Regulator

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NCP1402
200 mA, PFM Step−Up
Micropower Switching
Regulator
The NCP1402 series are monolithic micropower step−up DC to DC
converter that are specially designed for powering portable equipment
from one or two cell battery packs.These devices are designed to
start−up with a cell voltage of 0.8 V and operate down to less than
0.3 V. With only three external components, this series allow a simple
means to implement highly efficient converters that are capable of up
to 200 mA of output current at Vin = 2.0 V, VOUT = 3.0 V.
Each device consists of an on−chip PFM (Pulse Frequency
Modulation) oscillator, PFM controller, PFM comparator, soft−start,
voltage reference, feedback resistors, driver, and power MOSFET
switch with current limit protection. Additionally, a chip enable
feature is provided to power down the converter for extended battery
life.
The NCP1402 device series are available in the Thin SOT−23−5
package with five standard regulated output voltages. Additional
voltages that range from 1.8 V to 5.0 V in 100 mV steps can be
manufactured.
Features
Extremely Low Start−Up Voltage of 0.8 V
Operation Down to Less than 0.3 V
High Efficiency 85% (Vin = 2.0 V, VOUT = 3.0 V, 70 mA)
Low Operating Current of 30 mA (VOUT = 1.9 V)
Output Voltage Accuracy ± 2.5%
Low Converter Ripple with Typical 30 mV
Only Three External Components Are Required
Chip Enable Power Down Capability for Extended Battery Life
Micro Miniature Thin SOT−23−5 Packages
Typical Applications
Cellular Telephones
Pagers
Personal Digital Assistants (PDA)
Electronic Games
Portable Audio (MP3)
Camcorders
Digital Cameras
Handheld Instruments
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5
1
SOT23−5
(TSOP−5, SC59−5)
SN SUFFIX
CASE 483
PIN CONNECTIONS AND
MARKING DIAGRAM
CE 1
OUT 2
NC 3
5 LX
4 GND
xxx = Marking
Y = Year
W = Work Week
(Top View)
ORDERING INFORMATION
See detailed ordering and shipping information in the ordering
information section on page 3 of this data sheet.
© Semiconductor Components Industries, LLC, 2003
November, 2003 − Rev. 5
1
Publication Order Number:
NCP1402/D


CD54-470L (ON)
200 mA/ PFM Step-Up Micropower Switching Regulator

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OUT
2
NC
3
GND
4
NCP1402
Vin
CE LX
15
OUT NCP1402
2
NC GND
34
VOUT
Figure 1. Typical Step−Up Converter Application
VLX LIMITER
PFM
COMPARATOR
+
VOLTAGE
REFERENCE
SOFT−START
DRIVER
PFM
CONTROLLER
PFM
OSCILLATOR
LX
5
POWER
SWITCH
1 CE
Figure 2. Representative Block Diagram
PIN FUNCTION DESCRIPTIONS
Pin #
1
2
3
4
5
Symbol
CE
OUT
NC
GND
LX
Pin Description
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
Output voltage monitor pin, also the power supply pin of the device
No internal connection to this pin
Ground pin
External inductor connection pin to power switch drain
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200 mA/ PFM Step-Up Micropower Switching Regulator

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NCP1402
ORDERING INFORMATION
Device
Output Voltage
Device Marking
Package
Shipping
NCP1402SN19T1
1.9 V
DAU
NCP1402SN27T1
2.7 V
DAE
NCP1402SN30T1
NCP1402SN33T1
3.0 V
3.3 V
DAF
DAG
SOT23−5
3000 Units Per Reel
NCP1402SN40T1
4.0 V
DCR
NCP1402SN50T1
5.0 V
DAH
NOTE: The ordering information lists five standard output voltage device options. Additional device with output voltage ranging from 1.8 V to
5.0 V in 100 mV increments can be manufactured. Contact your ON Semiconductor representative for availability.
ABSOLUTE MAXIMUM RATINGS
Rating
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁPower Supply Voltage (Pin 2)
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁInput/Output Pins
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁLX (Pin 5)
Á ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁLX Peak Sink Current
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁCE (Pin 1)
Input Voltage Range
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁInput Current Range
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁThermal Resistance Junction to Air
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁOperating Ambient Temperature Range (Note 2)
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁOperating Junction Temperature Range
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁStorage Temperature Range
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁNOTES:
Symbol
VOUT
VLX
ILX
VCE
ICE
RθJA
TA
TJ
Tstg
Value
6.0
−0.3 to 6.0
400
−0.3 to 6.0
−150 to 150
250
−40 to +85
−40 to +125
−55 to +150
Unit
V
V
mA
V
mA
°C/W
°C
°C
°C
1. This device series contains ESD protection and exceeds the following tests:
Human Body Model (HBM) ±2.0 kV per JEDEC standard: JESD22−A114.
Machine Model (MM) ±200 V per JEDEC standard: JESD22−A115.
2. The maximum package power dissipation limit must not be exceeded.
PD
+
TJ(max) *
RqJA
TA
3. Latch−up Current Maximum Rating: ±150 mA per JEDEC standard: JESD78.
4. Moisture Sensitivity Level: MSL 1 per IPC/JEDEC standard: J−STD−020A.
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200 mA/ PFM Step-Up Micropower Switching Regulator

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NCP1402
ELECTRICAL CHARACTERISTICS (For all values TA = 25°C, unless otherwise noted.)
Characteristic
Symbol
Min
OSCILLATOR
Switch On Time (current limit not asserted)
Switch Minimum Off Time
Maximum Duty Cycle
Minimum Start−up Voltage (IO = 0 mA)
Minimum Start−up Voltage Temperature Coefficient (TA = −40°C to 85°C)
Minimum Operation Hold Voltage (IO = 0 mA)
Soft−Start Time (VOUT u 0.8 V)
LX (PIN 5)
Internal Switching N−Channel FET Drain Voltage
LX Pin On−State Sink Current (VLX = 0.4 V)
Device Suffix:
19T1
27T1
30T1
33T1
40T1
50T1
Voltage Limit
Off−State Leakage Current (VLX = 6.0 V, TA = −40°C to 85°C)
CE (PIN 1)
CE Input Voltage (VOUT = VSET x 0.96)
High State, Device Enabled
Low State, Device Disabled
CE Input Current (Note 6)
High State, Device Enabled (VOUT = VCE = 6.0 V)
Low State, Device Disabled (VOUT = 6.0 V, VCE = 0 V)
TOTAL DEVICE
Output Voltage
Device Suffix:
19T1
27T1
30T1
33T1
40T1
50T1
Output Voltage Temperature Coefficient (TA = −40°C to +85°C)
Device Suffix:
19T1
27T1
30T1
33T1
40T1
50T1
Operating Current 2 (VOUT = VCE = VSET +0.5 V, Note 5)
Off−State Current (VOUT = 5.0 V, VCE = 0 V, TA = −40°C to +85°C, Note 6)
Operating Current 1 (VOUT = VCE = VSET x 0.96)
Device Suffix:
19T1
27T1
30T1
33T1
40T1
50T1
5. VSET means setting of output voltage.
6. CE pin is integrated with an internal 10 Mpull−up resistor.
ton
toff
DMAX
Vstart
DVstart
Vhold
tSS
VLX
ILX
VLXLIM
ILKG
VCE(high)
VCE(low)
ICE(high)
ICE(low)
VOUT
DVOUT
IDD2
IOFF
IDD1
3.6
1.0
70
0.3
0.3
110
130
130
130
130
130
0.45
0.9
−0.5
−0.5
1.853
2.632
2.925
3.218
3.900
4.875
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4
Typ
5.5
1.45
78
0.8
−1.6
2.0
145
180
190
200
210
215
0.65
0.5
0
0.15
1.9
2.7
3.0
3.3
4.0
5.0
150
150
150
150
150
150
13
0.6
30
39
42
45
55
70
Max Unit
7.6 ms
1.9 ms
85 %
0.95 V
− mV/°C
−V
− ms
6.0 V
mA
0.9 V
1.0 µA
V
0.3
µA
0.5
0.5
1.948
2.768
3.075
3.383
4.100
5.125
15
1.0
50
60
60
60
100
100
V
ppm/°C
µA
µA
µA


CD54-470L (ON)
200 mA/ PFM Step-Up Micropower Switching Regulator

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NCP1402
2.1
NCP1402SN19T1
L = 47 µH
2.0 TA = 25°C
1.9
Vin = 0.9 V
Vin = 1.5 V
1.8 Vin = 1.2 V
1.7
4.0
NCP1402SN30T1
L = 47 µH
3.5 TA = 25°C
3.0
Vin = 0.9 V
Vin = 1.5 V
2.5 Vin = 1.2 V
Vin = 2.5 V
Vin = 2.0 V
2.0
1.6
0 20 40 60 80 100 120 140 160 180 200
IO, OUTPUT CURRENT (mA)
Figure 3. NCP1402SN19T1 Output Voltage vs.
Output Current
1.5
0 20 40 60 80 100 120 140 160 180 200
IO, OUTPUT CURRENT (mA)
Figure 4. NCP1402SN30T1 Output Voltage vs.
Output Current
6.0
5.0
4.0 Vin = 1.2 V
Vin = 0.9 V
3.0
Vin = 1.5 V
Vin = 4.0 V
Vin = 2.0 V
Vin = 3.0 V
100
80 Vin = 1.5 V
60
Vin = 0.9 V Vin = 1.2 V
40
2.0 NCP1402SN50T1
L = 47 µH
TA = 25°C
1.0
0 20 40 60 80 100 120 140 160 180 200
IO, OUTPUT CURRENT (mA)
Figure 5. NCP1402SN50T1 Output Voltage vs.
Output Current
20 NCP1402SN19T1
L = 47 µH
TA = 25°C
0
0 20 40 60 80 100 120 140 160 180 200
IO, OUTPUT CURRENT (mA)
Figure 6. NCP1402SN19T1 Efficiency vs.
Output Current
100
80
60
Vin = 0.9 V
40
Vin = 1.2 V
Vin = 2.5 V
Vin = 2.0 V
Vin = 1.5 V
100
80
Vin = 1.2 V
60
Vin = 0.9 V
40
Vin = 1.5 V
Vin = 4.0 V
Vin = 3.0 V
Vin = 2.0 V
20 NCP1402SN30T1
L = 47 µH
TA = 25°C
0
0 20 40 60 80 100 120 140 160 180 200
IO, OUTPUT CURRENT (mA)
Figure 7. NCP1402SN30T1 Efficiency vs.
Output Current
20 NCP1402SN50T1
L = 47 µH
TA = 25°C
0
0 20 40 60 80 100 120 140 160 180 200
IO, OUTPUT CURRENT (mA)
Figure 8. NCP1402SN50T1 Efficiency vs.
Output Current
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200 mA/ PFM Step-Up Micropower Switching Regulator

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NCP1402
2.1 3.2
2.0 3.1
1.9 3.0
1.8 2.9
1.7 NCP1402SN19T1
VOUT = 1.9 V x 0.96
Open−Loop Test
1.6
−50
−25
0
25
50
TEMPERATURE (°C)
75 100
Figure 9. NCP1402SN19T1 Output Voltage vs.
Temperature
2.8 NCP1402SN30T1
VOUT = 3.0 V x 0.96
Open−Loop Test
2.7
−50
−25
0
25
50
TEMPERATURE (°C)
75 100
Figure 10. NCP1402SN30T1 Output Voltage vs.
Temperature
5.2
NCP1402SN50T1
VOUT = 5.0 V x 0.96
5.1 Open−Loop Test
5.0
100
NCP1402SN19T1
VOUT = 1.9 V x 0.96
80 Open−Loop Test
60
4.9 40
4.8 20
4.7
−50
−25
0 25 50
TEMPERATURE (°C)
75 100
Figure 11. NCP1402SN50T1 Output Voltage vs.
Temperature
0
−50 −25
0
25 50
TEMPERATURE (°C)
75 100
Figure 12. NCP1402SN19T1 Operating
Current 1 vs. Temperature
100
NCP1402SN30T1
VOUT = 3.0 V x 0.96
80 Open−Loop Test
100
NCP1402SN50T1
VOUT = 5.0 V x 0.96
80 Open−Loop Test
60 60
40 40
20 20
0
−50 −25
0 25 50
TEMPERATURE (°C)
75
Figure 13. NCP1402SN30T1 Operating
Current 1 vs. Temperature
100
0
−50 −25
0 25 50
TEMPERATURE (°C)
75 100
Figure 14. NCP1402SN50T1 Operating
Current 1 vs. Temperature
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200 mA/ PFM Step-Up Micropower Switching Regulator

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NCP1402
7.5 7.5
7.0 7.0
6.5 6.5
6.0 6.0
5.5 NCP1402SN19T1
VOUT = 1.9 V x 0.96
Open−Loop Test
5.0
−50
−25
0
25
50
TEMPERATURE (°C)
75 100
Figure 15. NCP1402SN19T1 Switch On Time
vs. Temperature
5.5 NCP1402SN30T1
VOUT = 3.0 V x 0.96
Open−Loop Test
5.0
−50
−25
0
25
50
TEMPERATURE (°C)
75 100
Figure 16. NCP1402SN30T1 Switch On Time
vs. Temperature
7.0 1.9
6.5 1.8
6.0 1.7
5.5 1.6
5.0 NCP1402SN50T1
VOUT = 5.0 V x 0.96
Open−Loop Test
4.5
−50
−25
0
25
50
TEMPERATURE (°C)
75 100
Figure 17. NCP1402SN50T1 Switch On Time
vs. Temperature
1.5 NCP1402SN19T1
VOUT = 1.9 V x 0.96
Open−Loop Test
1.4
−50 −25
0
25
50
TEMPERATURE (°C)
75 100
Figure 18. NCP1402SN19T1 Minimum Switch
Off Time vs. Temperature
1.8 1.8
1.7 1.7
1.6 1.6
1.5 1.5
1.4 NCP1402SN30T1
VOUT = 3.0 V x 0.96
Open−Loop Test
1.3
−50 −25
0
25
50
TEMPERATURE (°C)
75 100
Figure 19. NCP1402SN30T1 Minimum Switch
Off Time vs. Temperature
1.4 NCP1402SN50T1
VOUT = 5.0 V x 0.96
Open−Loop Test
1.3
−50 −25
0
25
50
TEMPERATURE (°C)
75 100
Figure 20. NCP1402SN50T1 Minimum Switch
Off Time vs. Temperature
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200 mA/ PFM Step-Up Micropower Switching Regulator

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NCP1402
100
90
80
70
60
50
NCP1402SN19T1
VOUT = 1.9 V x 0.96
Open−Loop Test
40
−50 −25
0
25
50
TEMPERATURE (°C)
75 100
Figure 21. NCP1402SN19T1 Maximum Duty
Cycle vs. Temperature
100
90
80
70
60
NCP1402SN30T1
50 VOUT = 3.0 V x 0.96
Open−Loop Test
40
−50 −25
0
25
50
TEMPERATURE (°C)
75 100
Figure 22. NCP1402SN30T1 Maximum Duty
Cycle vs. Temperature
100
90
80
70
60
NCP1402SN50T1
50 VOUT = 5.0 V x 0.96
Open−Loop Test
40
−50 −25
0
25
50
TEMPERATURE (°C)
75 100
Figure 23. NCP1402SN50T1 Maximum Duty
Cycle vs. Temperature
200
180
160
140
NCP1402SN19T1
120 VOUT = 1.9 V x 0.96
VLX = 0.4 V
Open−Loop Test
100
−50
−25
0
25
50
TEMPERATURE (°C)
75 100
Figure 24. NCP1402SN19T1 LX Pin On−State
Current vs. Temperature
250 300
230 275
210 250
190
NCP1402SN30T1
170 VOUT = 3.0 V x 0.96
VLX = 0.4 V
Open−Loop Test
150
−50 −25
0
25
50
TEMPERATURE (°C)
75 100
Figure 25. NCP1402SN30T1 LX Pin On−State
Current vs. Temperature
225
NCP1402SN50T1
200 VOUT = 5.0 V x 0.96
VLX = 0.4 V
Open−Loop Test
175
−50
−25
0
25
50
TEMPERATURE (°C)
75 100
Figure 26. NCP1402SN50T1 LX Pin On−State
Current vs. Temperature
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200 mA/ PFM Step-Up Micropower Switching Regulator

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NCP1402
1.0 1.0
0.8 0.8
0.6 0.6
0.4 0.4
0.2
NCP1402SN19T1
Open−Loop Test
0.0
−50
−25
0
25 50
TEMPERATURE (°C)
75 100
Figure 27. NCP1402SN19T1 VLX Voltage Limit
vs. Temperature
0.2
NCP1402SN30T1
Open−Loop Test
0.0
−50
−25
0
25 50
TEMPERATURE (°C)
75 100
Figure 28. NCP1402SN30T1 VLX Voltage Limit
vs. Temperature
1.0
0.8
0.6
0.4
0.2
NCP1402SN50T1
Open−Loop Test
0.0
−50
−25
0
25 50
TEMPERATURE (°C)
75 100
Figure 29. NCP1402SN50T1 VLX Voltage Limit
vs. Temperature
4.0
3.5
3.0
2.5
2.0
NCP1402SN19T1
1.5 VOUT = 1.9 V x 0.96
VLX = 0.4 V
Open−Loop Test
1.0
−50 −25
0
25
50
TEMPERATURE (°C)
75 100
Figure 30. NCP1402SN19T1 Switch−on
Resistance vs. Temperature
3.0
2.5
2.0
1.5
1.0
NCP1402SN30T1
0.5
VOUT = 3.0 V x 0.96
VLX = 0.4 V
Open−Loop Test
0.0
−50 −25
0
25
50
TEMPERATURE (°C)
75 100
Figure 31. NCP1402SN30T1 Switch−on
Resistance vs. Temperature
3.0
2.5
2.0
1.5
1.0
NCP1402SN50T1
0.5
VOUT = 5.0 V x 0.96
VLX = 0.4 V
Open−Loop Test
0.0
−50 −25
0
25
50
TEMPERATURE (°C)
75 100
Figure 32. NCP1402SN50T1 Switch−on
Resistance vs. Temperature
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200 mA/ PFM Step-Up Micropower Switching Regulator

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NCP1402
1.0
Vstart
0.8
1.0
Vstart
0.8
0.6 NCP1402SN19T1
L = 22 µH
COUT = 10 µF
0.4 IO = 0 mA
0.6 NCP1402SN30T1
L = 22 µH
COUT = 10 µF
0.4 IO = 0 mA
0.2
Vhold
0.0
−50
−25
0 25 50
TEMPERATURE (°C)
75 100
Figure 33. NCP1402SN19T1 Startup/Hold
Voltage vs. Temperature
0.2 Vhold
0.0
−50
−25
0 25 50
TEMPERATURE (°C)
75 100
Figure 34. NCP1402SN30T1 Startup/Hold
Voltage vs. Temperature
1.0
Vstart
0.8
0.6 NCP1402SN50T1
L = 22 µH
COUT = 10 µF
0.4 IO = 0 mA
0.2 Vhold
0.0
−50
−25
0 25 50
TEMPERATURE (°C)
75 100
Figure 35. NCP1402SN50T1 Startup/Hold
Voltage vs. Temperature
2.0
1.5 Vstart
1.0 Vhold
0.5 NCP1402SN19T1
L = 47 µH
COUT = 68 µF
TA = 25°C
0.0
0 10 20 30 40 50 60 70 80 90 100
IO, OUTPUT CURRENT (mA)
Figure 36. NCP1402SN19T1 Startup/Hold
Voltage vs. Output Current
2.0 2.0
1.5 Vstart
1.0
Vhold
NCP1402SN30T1
0.5 L = 47 µH
COUT = 68 µF
TA = 25°C
0.0
0 10 20 30 40 50 60 70 80 90 100
IO, OUTPUT CURRENT (mA)
Figure 37. NCP1402SN30T1 Startup/Hold
Voltage vs. Output Current
1.5
Vstart
1.0
0.5 Vhold
NCP1402SN50T1
L = 47 µH
COUT = 68 µF
TA = 25°C
0.0
0 10 20 30 40 50 60 70 80 90 100
IO, OUTPUT CURRENT (mA)
Figure 38. NCP1402SN50T1 Startup/Hold
Voltage vs. Output Current
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200 mA/ PFM Step-Up Micropower Switching Regulator

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NCP1402
5 ms/div
VOUT = 1.9 V, Vin = 1.2 V, IO = 30 mA, L = 47 mH, COUT = 68 mF
1. VLX, 1.0 V/div
2. VOUT, 20 mV/div, AC coupled
3. IL, 100 mA/div
Figure 39. NCP1402SN19T1 Operating
Waveforms (Medium Load)
5 ms/div
VOUT = 1.9 V, Vin = 1.2 V, IO = 70 mA, L = 47 mH, COUT = 68 mF
1. VLX, 1.0 V/div
2. VOUT, 20 mV/div, AC coupled
3. IL, 100 mA/div
Figure 40. NCP1402SN19T1 Operating
Waveforms (Heavy Load)
2 ms/div
VOUT = 3.0 V, Vin = 1.2 V, IO = 30 mA, L = 47 mH, COUT = 68 mF
1. VLX, 2.0 V/div
2. VOUT, 20 mV/div, AC coupled
3. IL, 100 mA/div
Figure 41. NCP1402SN30T1 Operating
Waveforms (Medium Load)
2 ms/div
VOUT = 3.0 V, Vin = 1.2 V, IO = 70 mA, L = 47 mH, COUT = 68 mF
1. VLX, 2.0 V/div
2. VOUT, 20 mV/div, AC coupled
3. IL, 100 mA/div
Figure 42. NCP1402SN30T1 Operating
Waveforms (Heavy Load)
2 ms/div
VOUT = 5.0 V, Vin = 1.5 V, IO = 30 mA, L = 47 mH, COUT = 68 mF
1. VLX, 2.0 V/div
2. VOUT, 20 mV/div, AC coupled
3. IL, 100 mA/div
Figure 43. NCP1402SN50T1 Operating
Waveforms (Medium Load)
2 ms/div
VOUT = 5.0 V, Vin = 1.5 V, IO = 60 mA, L = 47 mH, COUT = 68 mF
1. VLX, 2.0 V/div
2. VOUT, 20 mV/div, AC coupled
3. IL, 100 mA/div
Figure 44. NCP1402SN50T1 Operating
Waveforms (Heavy Load)
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NCP1402
Vin = 1.2 V, L = 47 mH, COUT = 68 mF
1. VOUT = 1.9 V (AC coupled), 100 mV/div
2. IO = 0.1 mA to 80 mA
Figure 45. NCP1402SN19T1 Load Transient
Response
Vin = 1.2 V, L = 47 mH, COUT = 68 mF
1. VOUT = 1.9 V (AC coupled), 100 mV/div
2. IO = 80 mA to 0.1 mA
Figure 46. NCP1402SN19T1 Load Transient
Response
Vin = 1.5 V, L = 47 mH, COUT = 68 mF
1. VOUT = 3.0 V (AC coupled), 100 mV/div
2. IO = 0.1 mA to 80 mA
Figure 47. NCP1402SN30T1 Load Transient
Response
Vin = 1.5 V, L = 47 mH, COUT = 68 mF
1. VOUT = 3.0 V (AC coupled), 100 mV/div
2. IO = 80 mA to 0.1 mA
Figure 48. NCP1402SN30T1 Load Transient
Response
Vin = 2.4 V, L = 47 mH, COUT = 68 mF
1. VOUT = 5.0 V (AC coupled), 100 mV/div
2. IO = 0.1 mA to 80 mA
Figure 49. NCP1402SN50T1 Load Transient
Response
Vin = 2.4 V, L = 47 mH, COUT = 68 mF
1. VOUT = 5.0 V (AC coupled), 100 mV/div
2. IO = 80 mA to 0.1 mA
Figure 50. NCP1402SN50T1 Load Transient
Response
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NCP1402
100
NCP1402SN19T1
L = 47 µH
80 COUT = 68 mF
TA = 25°C
60
40 Vin = 1.5 V
Vin = 1.2 V
20
Vin = 0.9 V
0
0 20 40 60 80 100 120 140 160 180 200
IO, OUTPUT CURRENT (mA)
Figure 51. NCP1402SN19T1 Ripple Voltage vs.
Output Current
100
NCP1402SN30T1
L = 47 µH
80 COUT = 68 mF
TA = 25°C
60
Vin = 0.9 V
40
Vin = 1.2 V
Vin = 2.0 V
Vin = 1.5 V
Vin = 2.5 V
20
0
0 20 40 60 80 100 120 140 160 180 200
IO, OUTPUT CURRENT (mA)
Figure 52. NCP1402SN30T1 Ripple Voltage vs.
Output Current
100
Vin = 4.0 V
80
Vin = 2.0 V
60 Vin = 1.5 V
Vin = 1.2 V
40
Vin = 3.0 V
NCP1402SN50T1
20 L = 47 µH
COUT = 68 mF
Vin = 0.9 V
TA = 25°C
0
0 20 40 60 80 100 120 140 160 180 200
IO, OUTPUT CURRENT (mA)
Figure 53. NCP1402SN50T1 Ripple Voltage vs.
Output Current
100
80
85°C
25°C
60
−40°C
40
20 NCP1402SNXXT1
VOUT = VSET x 0.96
Open−loop Test
0
123 4 56
VOUT, OUTPUT VOLTAGE (V)
Figure 54. NCP1402SNXXT1 Operating
Current 1 vs. Output Voltage
300
−40°C
260
220 25°C
85°C
180
NCP1402SNXXT1
140 VOUT = VSET x 0.96
VLX = 0.4 V
Open−loop Test
100
123 4 5
VOUT, OUTPUT VOLTAGE (V)
Figure 55. NCP1402SNXXT1 Pin On−state
Current vs. Output Voltage
6
3.5
NCP1402SNXXT1
VOUT = VSET x 0.96
3.0 VLX = 0.4 V
Open−loop Test
2.5
85°C
2.0
25°C
1.5 −40°C
1.0
1
23 4 5
VOUT, OUTPUT VOLTAGE (V)
Figure 56. NCP1402SNXXT1 Switch−On
Resistance vs. Output Voltage
6
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NCP1402
150
5.0 V
125
100
3.3 V
75
3.0 V
50 2.7 V
25 1.9 V
NCP1402SNXXT1
L = 47 µH
IO = 0 mA
TA = 25°C
0
0 12
34
5
Vin, INPUT VOLTAGE (V)
Figure 57. NCP1402SNXXT1 No Load Input
Current vs. Input Voltage
6
400
3.3 V 5.0 V
3.0 V
300
2.7 V
200
1.9 V
100
NCP1402SNXXT1
L = 47 µH
TA = 25°C
0
0123 45
Vin, INPUT VOLTAGE (V)
Figure 58. NCP1402SNXXT1 Maximum Output
Current vs. Input Voltage
DETAILED OPERATING DESCRIPTION
Operation
The NCP1402 series are monolithic power switching
regulators optimized for applications where power drain
must be minimized. These devices operate as variable
frequency, voltage mode boost regulators and designed to
operate in continuous conduction mode. Potential
applications include low powered consumer products and
battery powered portable products.
The NCP1402 series are low noise variable frequency
voltage−mode DC−DC converters, and consist of soft−start
circuit, feedback resistor, reference voltage, oscillator, PFM
comparator, PFM control circuit, current limit circuit and
power switch. Due to the on−chip feedback resistor network,
the system designer can get the regulated output voltage
from 1.8 V to 5 V with a small number of external
components. The operating current is typically 30 mA
(VOUT = 1.9 V), and can be further reduced to about 0.6 mA
when the chip is disabled (VCE < 0.3 V).
The NCP1402 operation can be best understood by
examining the block diagram in Figure 2. PFM comparator
monitors the output voltage via the feedback resistor. When
the feedback voltage is higher than the reference voltage, the
power switch is turned off. As the feedback voltage is lower
than reference voltage and the power switch has been off for
at least a period of minimum off−time decided by PFM
oscillator, the power switch is then cycled on for a period of
on−time also decided by PFM oscillator, or until current
limit signal is asserted. When the power switch is on, current
ramps up in the inductor, storing energy in the magnetic
field. When the power switch is off, the energy in the
magnetic field is transferred to output filter capacitor and the
load. The output filter capacitor stores the charge while the
inductor current is high, then holds up the output voltage
until next switching cycle.
Soft Start
There is a soft start circuit in NCP1402. 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. What is more,
the start−up capability with heavy loads is also improved.
Regulated Converter Voltage (VOUT)
The VOUT is set by an internal feedback resistor network.
This is trimmed to a selected voltage from 1.8 to 5.0 V range
in 100 mV steps with an accuracy of $2.5%.
Current Limit
The NCP1402 series utilizes cycle−by−cycle current
limiting as a means of protecting the output switch
MOSFET from overstress and preventing the small value
inductor from saturation. Current limiting is implemented
by monitoring the output MOSFET current build−up during
conduction, and upon sensing an overcurrent conduction
immediately turning off the switch for the duration of the
oscillator cycle.
The voltage across the output MOSFET is monitored and
compared against a reference by the VLX limiter. When the
threshold is reached, a signal is sent to the PFM controller
block to terminate the power switch conduction. The current
limit threshold is typically set at 350 mA.
Enable / Disable Operation
The NCP1402 series offer IC shut−down mode by chip
enable pin (CE pin) to reduce current consumption. An
internal pull−up resistor 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 or greater than 0.9 V, the
chip will be enabled, which means the regulator is in normal
operation. When voltage at pin CE is less than 0.3 V, the chip
is disabled, which means IC is shutdown.
Important: DO NOT apply a voltage between 0.3 V and 0.9 V to pin CE as this is the CE pin’s hyteresis voltage
range. Clearly defined output states can only be obtained by applying voltage out of this range.
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NCP1402
APPLICATIONS CIRCUIT INFORMATION
Vin
C1
10 mF
L1
47 mH
CE LX
15
OUT NCP1402
2
NC GND
34
D1
VOUT
C2
68 mF
Figure 59. Typical Application Circuit
Step−up Converter Design Equations
NCP1402 step−up DC−DC converter designed to operate
in continuous conduction mode can be defined by:
Calculation
L
Equation
ǒ Ǔv M
Vin2
VOUT IOmax
IPK
(Vin
* Vs)ton
L
)
I
min
Imin
(ton
) toff)IO
toff
*
(Vin
* VS)ton
2L
toff
(Vin * Vs)ton
(VOUT ) VF * Vin)
DQ (IL * IO)toff
Vripple
[
DQ
COUT
)
(IL
*
IO)ESR
*NOTES:
IPK
Imin
IO
IOmax
IL
Vin
VOUT
VF
VS
DQ −
Vripple
ESR −
M−
Peak inductor current
Minimum inductor current
Desired dc output current
Desired maximum dc output current
Average inductor current
Nominal operating dc input voltage
Desired dc output voltage
Diode forward voltage
Saturation voltage of the internal FET switch
Charge stores in the COUT during charging up
Output ripple voltage
Equivalent series resistance of the output capacitor
An empirical factor, when VOUT 3.0 V,
M = 8 x 10−6, otherwise M = 5.3 x 10−6.
EXTERNAL COMPONENT SELECTION
Inductor
The NCP1402 is designed to work well with a 47 mH
inductor in most applications. 47 mH is a sufficiently low
value to allow the use of a small surface mount coil, but large
enough to maintain low ripple. Low inductance values
supply higher output current, but also increase the ripple and
reduce efficiency. Note that values below 27 mH is not
recommended due to NCP1402 switch limitations. Higher
inductor values reduce ripple and improve efficiency, but
also limit output current.
The inductor should have small DCR, usually less than 1
W to minimize loss. It is necessary to choose an inductor with
saturation current greater than the peak current which the
inductor will encounter in the application.
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:
Small forward voltage, VF < 0.3 V
Small reverse leakage current
Fast reverse recovery time/ switching speed
Rated current larger than peak inductor current,
Irated > IPK
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.
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NCP1402
Output Capacitor
The output capacitor is used for sustaining the output
voltage when the internal MOSFET is switched on and
smoothing the ripple voltage. Low ESR capacitor should be
used to reduce output ripple voltage. In general, a 47 uF to
68 uF low ESR (0.15 W to 0.30 W) Tantalum capacitor
should be appropriate. For applications where space is a
critical factor, two parallel 22 uF low profile SMD ceramic
capacitors can be used.
An evaluation board of NCP1402 has been made in the
size of 23 mm x 20 mm only, as shown in Figures 60 and 61.
Please contact your ON Semiconductor representative for
availability. The evaluation board schematic diagram, the
artwork and the silkscreen of the surface−mount PCB are
shown below:
20 mm
23 mm
Figure 60. NCP1402 PFM Step−Up DC−DC Converter Evaluation Board Silkscreen
20 mm
23 mm
Figure 61. NCP1402 PFM Step−Up DC−DC Converter Evaluation Board Artwork (Component Side)
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NCP1402
Components Supplier
Parts
Inductor, L1
Schottky Diode, D1
Output Capacitor, C2
Input Capacitor, C1
Supplier
Sumida Electric Co. Ltd.
ON Semiconductor Corp.
Part Number
CD54−470L
MBR0520LT1
KEMET Electronics Corp. T494D686K010AS
KEMET Electronics Corp. T491C106K016AS
Description
Inductor 47 mH / 0.72 A
Schottky Power Rectifier
Low ESR Tantalum Capacitor
68 mF / 10 V
Low Profile Tantalum Capacitor
10 mF / 16 V
Phone
(852)−2880−6688
(852)−2689−0088
(852)−2305−1168
(852)−2305−1168
PCB Layout Hints
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 as shown in Figure 62, e.g. :
C2 GND, C1 GND, and U1 GND are connected at one point
in the evaluation board. The input ground and output ground
traces must be thick enough for current to flow through and
for reducing ground bounce.
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), e.g. : short and thick
traces listed below are used in the evaluation board:
1. Trace from TP1 to L1
2. Trace from L1 to Lx pin of U1
3. Trace from L1 to anode pin of D1
4. Trace from cathode pin of D1 to TP2
Output Capacitor
The output capacitor should be placed close to the output
terminals to obtain better smoothing effect on the output
ripple.
TP1
Vin
L1
47 µH
D1
MBR0520LT1
TP2
Vout
C1 + JP1
10 µF/16 V
Enable
On
Off
CE LX
15
OUT NCP1402
+
C2
68 µF/10 V
TP4
GND
2
NC GND
36
TP3
GND
Figure 62. NCP1402 Evaluation Board Schematic Diagram
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D
54
S 1 23
L
G
A
B
0.05 (0.002)
H
C
NCP1402
PACKAGE DIMENSIONS
SOT23−5
(TSOP−5, SC59−5)
SN SUFFIX
CASE 483−02
ISSUE C
J
KM
NOTES:
1. DIMENSIONING AND TOLERANCING PER
ANSI Y14.5M, 1982.
2. CONTROLLING DIMENSION: MILLIMETER.
3. MAXIMUM LEAD THICKNESS INCLUDES
LEAD FINISH THICKNESS. MINIMUM LEAD
THICKNESS IS THE MINIMUM THICKNESS
OF BASE MATERIAL.
4. A AND B DIMENSIONS DO NOT INCLUDE
MOLD FLASH, PROTRUSIONS, OR GATE
BURRS.
MILLIMETERS INCHES
DIM MIN MAX MIN MAX
A 2.90 3.10 0.1142 0.1220
B 1.30 1.70 0.0512 0.0669
C 0.90 1.10 0.0354 0.0433
D 0.25 0.50 0.0098 0.0197
G 0.85 1.05 0.0335 0.0413
H 0.013 0.100 0.0005 0.0040
J 0.10 0.26 0.0040 0.0102
K 0.20 0.60 0.0079 0.0236
L 1.25 1.55 0.0493 0.0610
M 0 _ 10 _ 0 _ 10 _
S 2.50 3.00 0.0985 0.1181
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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