© Semiconductor Components Industries, LLC, 2007
May, 2007 - Rev. 8
1Publication Order Number:
NCP1402/D
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
startup 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 Startup 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 A (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
•Pb-Free Packages are Available
Typical Applications
•Cellular Telephones
•Pagers
•Personal Digital Assistants (PDA)
•Electronic Games
•Portable Audio (MP3)
•Camcorders
•Digital Cameras
•Handheld Instruments
ORDERING INFORMATION
SOT23-5
(TSOP-5, SC59-5)
SN SUFFIX
CASE 483
1
5
PIN CONNECTIONS AND
MARKING DIAGRAM
1
3GND
CE
2
OUT
NC 4
LX
5
(Top View)
xxx = Marking
A = Assembly Location
Y = Year
W = Work Week
G= Pb-Free Package
See detailed ordering and shipping information in the ordering
information section on page 18 of this data sheet.
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xxxAYW G
G
(Note: Microdot may be in either location)
NCP1402
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2
1
3
GND
CE
2
OUT
NC
4
LX
5
NCP1402
Figure 1. Typical Step-Up Converter Application
VOUT
Vin
POWER
SWITCH
OUT
2
-
+
VOLTAGE
REFERENCE SOFT-ST ART
PFM
CONTROLLER
PFM
OSCILLATOR
DRIVER
VLX LIMITER
PFM
COMPARATOR
NC
3
GND
4
LX
5
1 CE
Figure 2. Representative Block Diagram
PIN FUNCTION DESCRIPTIONS
Pin # Symbol Pin 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 OUT Output voltage monitor pin, also the power supply pin of the device
3 NC No internal connection to this pin
4 GND Ground pin
5 LX External inductor connection pin to power switch drain
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3
ABSOLUTE MAXIMUM RATINGS
Rating Symbol Value Unit
Power Supply Voltage (Pin 2) VOUT 6.0 V
Input/Output Pins
LX (Pin 5)
LX Peak Sink Current
VLX
ILX
-0.3 to 6.0
400
V
mA
CE (Pin 1)
Input Voltage Range
Input Current Range
VCE
ICE
-0.3 to 6.0
-150 to 150
V
mA
Thermal Resistance, Junction-to-Air RJA 250 °C/W
Operating Ambient Temperature Range (Note 2) TA-40 to +85 °C
Operating Junction Temperature Range TJ-40 to +125 °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.
NOTES:
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) *TA
RJA
3. Latchup 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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4
ELECTRICAL CHARACTERISTICS (For all values TA = 25°C, unless otherwise noted.)
Characteristic Symbol Min Typ Max Unit
OSCILLATOR
Switch On Time (current limit not asserted) ton 3.6 5.5 7.6 s
Switch Minimum Off Time toff 1.0 1.45 1.9 s
Maximum Duty Cycle DMAX 70 78 85 %
Minimum Startup Voltage (IO = 0 mA) Vstart - 0.8 0.95 V
Minimum Startup Voltage Temperature Coefficient (TA = -40°C to 85°C) Vstart - -1.6 - mV/°C
Minimum Operation Hold Voltage (IO = 0 mA) Vhold 0.3 - - V
Soft-Start Time (VOUT u 0.8 V) tSS 0.3 2.0 - ms
LX (PIN 5)
Internal Switching N-Channel FET Drain Voltage VLX - - 6.0 V
LX Pin On-State Sink Current (VLX = 0.4 V)
Device Suffix:
19T1
27T1
30T1
33T1
40T1
50T1
ILX
110
130
130
130
130
130
145
180
190
200
210
215
-
-
-
-
-
-
mA
Voltage Limit VLXLIM 0.45 0.65 0.9 V
Off-State Leakage Current (VLX = 6.0 V, TA = -40°C to 85°C) ILKG - 0.5 1.0 A
CE (PIN 1)
CE Input Voltage (VOUT = VSET x 0.96)
High State, Device Enabled
Low State, Device Disabled
VCE(high)
VCE(low)
0.9
-
-
-
-
0.3
V
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)
ICE(high)
ICE(low)
-0.5
-0.5
0
0.15
0.5
0.5
A
TOTAL DEVICE
Output Voltage
Device Suffix:
19T1
27T1
30T1
33T1
40T1
50T1
VOUT
1.853
2.632
2.925
3.218
3.900
4.875
1.9
2.7
3.0
3.3
4.0
5.0
1.948
2.768
3.075
3.383
4.100
5.125
V
Output Voltage Temperature Coefficient (TA = -40°C to +85°C)
Device Suffix:
19T1
27T1
30T1
33T1
40T1
50T1
VOUT
-
-
-
-
-
-
150
150
150
150
150
150
-
-
-
-
-
-
ppm/°C
Operating Current 2 (VOUT = VCE = VSET +0.5 V, Note 5) IDD2 - 13 15 A
Off-State Current (VOUT = 5.0 V, VCE = 0 V, TA = -40°C to +85°C, Note 6) IOFF - 0.6 1.0 A
Operating Current 1 (VOUT = VCE = VSET x 0.96)
Device Suffix:
19T1
27T1
30T1
33T1
40T1
50T1
IDD1
-
-
-
-
-
-
30
39
42
45
55
70
50
60
60
60
100
100
A
5. VSET means setting of output voltage.
6. CE pin is integrated with an internal 10 M pullup resistor.
NCP1402
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5
100
60
80
40
20
0
3.0
2.0
3.5
2.5
1.5
4.0
40
0
1.9
604020
VOUT
, OUTPUT VOLTAGE (V)
1.6
IO, OUTPUT CURRENT (mA)
Figure 3. NCP1402SN19T1 Output Voltage vs.
Output Current
Figure 4. NCP1402SN30T1 Output Voltage vs.
Output Current
VOUT
, OUTPUT VOLTAGE (V)
6.0
5.0
4.0
3.0
1.0
Figure 5. NCP1402SN50T1 Output Voltage vs.
Output Current
IO, OUTPUT CURRENT (mA)
Figure 6. NCP1402SN19T1 Efficiency vs.
Output Current
IO, OUTPUT CURRENT (mA)
EFFICIENCY (%)
VOUT
, OUTPUT VOLTAGE (V)
Figure 7. NCP1402SN30T1 Efficiency vs.
Output Current
IO, OUTPUT CURRENT (mA)
Figure 8. NCP1402SN50T1 Efficiency vs.
Output Current
IO, OUTPUT CURRENT (mA)
EFFICIENCY (%)
2.1
20
60
0
80
100
Vin = 0.9 V
NCP1402SN19T1
L = 47 H
TA = 25°C
IO, OUTPUT CURRENT (mA)
1.7
1.8
2.0
80 100 120 140 160 180 200 0 604020 80 100 120 140 160 180 200
2.0
0604020 80 100 120 140 160 180 200 0 604020 80 100 120 140 160 180 200
0604020 80 100 120 140 160 180 200
100
60
80
40
20
0
0604020 80 100 120 140 160 180 200
EFFICIENCY (%)
Vin = 1.2 V
Vin = 1.5 V Vin = 0.9 V
Vin = 1.2 V
Vin = 1.5 V
Vin = 2.5 V
Vin = 2.0 V
NCP1402SN30T1
L = 47 H
TA = 25°C
Vin = 0.9 V
Vin = 1.2 V
Vin = 1.5 V
Vin = 4.0 V
Vin = 2.0 V
Vin = 3.0 V Vin = 0.9 V Vin = 1.2 V
Vin = 1.5 V
Vin = 0.9 V Vin = 1.2 V Vin = 1.5 V
Vin = 2.0 V
Vin = 2.5 V
Vin = 0.9 V
Vin = 1.2 V Vin = 1.5 V Vin = 2.0 V
Vin = 3.0 V
Vin = 4.0 V
NCP1402SN19T1
L = 47 H
TA = 25°C
NCP1402SN50T1
L = 47 H
TA = 25°C
NCP1402SN50T1
L = 47 H
TA = 25°C
NCP1402SN30T1
L = 47 H
TA = 25°C
NCP1402
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6
100
60
80
40
20
00
20
40
60
80
100
3.1
2.9
2.8
3.0
2.7
3.2
60
-50
2.0
250-25
VOUT
, OUTPUT VOLTAGE (V)
1.6
TEMPERATURE (°C)
Figure 9. NCP1402SN19T1 Output Voltage vs.
Temperature
Figure 10. NCP1402SN30T1 Output Voltage vs.
Temperature
VOUT
, OUTPUT VOLTAGE (V)
5.2
5.1
5.0
4.9
4.8
4.7
Figure 11. NCP1402SN50T1 Output Voltage vs.
Temperature
TEMPERATURE (°C)
Figure 12. NCP1402SN19T1 Operating
Current 1 vs. Temperature
TEMPERATURE (°C)
IDD1, OPERATING CURRENT 1 (mA)
VOUT
, OUTPUT VOLTAGE (V)
Figure 13. NCP1402SN30T1 Operating
Current 1 vs. Temperature
TEMPERATURE (°C)
Figure 14. NCP1402SN50T1 Operating
Current 1 vs. Temperature
TEMPERATURE (°C)
IDD1, OPERATING CURRENT 1 (mA)
IDD1, OPERATING CURRENT 1 (mA)
2.1
20
80
40
0
100
TEMPERATURE (°C)
1.7
1.8
1.9
50 75 100 -50 250-25 50 75 10
0
-50 250-25 50 75 100 -50 250-25 50 75 10
0
-50 250-25 50 75 100 -50 250-25 50 75 100
NCP1402SN19T1
VOUT = 1.9 V x 0.96
Open-Loop Test
NCP1402SN30T1
VOUT = 3.0 V x 0.96
Open-Loop Test
NCP1402SN50T1
VOUT = 5.0 V x 0.96
Open-Loop Test
NCP1402SN19T1
VOUT = 1.9 V x 0.96
Open-Loop Test
NCP1402SN30T1
VOUT = 3.0 V x 0.96
Open-Loop Test
NCP1402SN50T1
VOUT = 5.0 V x 0.96
Open-Loop Test
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1.5
-50
6.5
25
5.5
0-25
ton, SWITCH ON TIME (s)
5.0
TEMPERATURE (°C)
Figure 15. NCP1402SN19T1 Switch On Time
vs. Temperature
Figure 16. NCP1402SN30T1 Switch On Time
vs. Temperature
ton, SWITCH ON TIME (s)
7.0
6.5
6.0
5.5
5.0
4.5
Figure 17. NCP1402SN50T1 Switch On Time
vs. Temperature
TEMPERATURE (°C)
Figure 18. NCP1402SN19T1 Minimum Switch
Off Time vs. Temperature
TEMPERATURE (°C)
toff, MINIMUM SWITCH OFF TIME (s)
ton, SWITCH ON TIME (s)
Figure 19. NCP1402SN30T1 Minimum Switch
Off Time vs. Temperature
TEMPERATURE (°C)
Figure 20. NCP1402SN50T1 Minimum Switch
Off Time vs. Temperature
TEMPERATURE (°C)
toff, MINIMUM SWITCH OFF TIME (s)
7.5
1.6
1.4
1.7
1.9
TEMPERATURE (°C)
6.0
7.0
50 75 100
6.5
5.5
5.0
7.5
6.0
7.0
-50 250-25 50 75 100
-50 250-25 50 75 100
-50 250-25 50 75 100 -50 250-25 50 75 100
1.5
1.6
1.4
1.3
1.7
1.8
1.5
1.6
1.4
1.3
1.7
1.8
toff, MINIMUM SWITCH OFF TIME (s)
NCP1402SN19T1
VOUT = 1.9 V x 0.96
Open-Loop Test
NCP1402SN30T1
VOUT = 3.0 V x 0.96
Open-Loop Test
NCP1402SN50T1
VOUT = 5.0 V x 0.96
Open-Loop Test
NCP1402SN19T1
VOUT = 1.9 V x 0.96
Open-Loop Test
NCP1402SN30T1
VOUT = 3.0 V x 0.96
Open-Loop Test
NCP1402SN50T1
VOUT = 5.0 V x 0.96
Open-Loop Test
-50 250-25 50 75 100
1.8
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8
250
230
190
210
170
150
200
225
250
275
300
160
90
60
DMAX, MAXIMUM DUTY CYCLE (%)
40
TEMPERATURE (°C)
Figure 21. NCP1402SN19T1 Maximum Duty
Cycle vs. Temperature
Figure 22. NCP1402SN30T1 Maximum Duty
Cycle vs. Temperature
100
70
60
90
50
40
Figure 23. NCP1402SN50T1 Maximum Duty
Cycle vs. Temperature
TEMPERATURE (°C)
Figure 24. NCP1402SN19T1 LX Pin On-State
Current vs. Temperature
TEMPERATURE (°C)
ILX, LX PIN ON-STATE CURRENT (mA)
Figure 25. NCP1402SN30T1 LX Pin On-State
Current vs. Temperature
TEMPERATURE (°C)
Figure 26. NCP1402SN50T1 LX Pin On-State
Current vs. Temperature
TEMPERATURE (°C)
100
120
180
140
100
200
TEMPERATURE (°C)
50
70
80
-50 250-25 50 75 100 -50 250-25 50 75 100
-50 250-25 50 75 100-50 250-25 50 75 100
-50 250-25 50 75 100 -50 250-25 50 75 100
175
NCP1402SN19T1
VOUT = 1.9 V x 0.96
Open-Loop Test
NCP1402SN30T1
VOUT = 3.0 V x 0.96
Open-Loop Test
NCP1402SN50T1
VOUT = 5.0 V x 0.96
Open-Loop Test
NCP1402SN19T1
VOUT = 1.9 V x 0.96
VLX = 0.4 V
Open-Loop Test
NCP1402SN50T1
VOUT = 5.0 V x 0.96
VLX = 0.4 V
Open-Loop Test
NCP1402SN30T1
VOUT = 3.0 V x 0.96
VLX = 0.4 V
Open-Loop Test
DMAX, MAXIMUM DUTY CYCLE (%)
100
90
80
70
60
50
40
DMAX, MAXIMUM DUTY CYCLE (%)
80
ILX, LX PIN ON-STATE CURRENT (mA)
ILX, LX PIN ON-STATE CURRENT (mA)
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0.8
0.2
0.0
1.0
0.4
0.6
-50 250-25 50 75 100
3.0
2.5
1.0
1.5
0.5
0.0
2.5
0.8
0.2
VLXLIM, VLX VOLTAGE LIMIT (V)
0.0
TEMPERATURE (°C)
Figure 27. NCP1402SN19T1 VLX Voltage Limit
vs. Temperature
Figure 28. NCP1402SN30T1 VLX Voltage Limit
vs. Temperature
VLXLIM, VLX VOLTAGE LIMIT (V)
Figure 29. NCP1402SN50T1 VLX Voltage Limit
vs. Temperature
TEMPERATURE (°C)
Figure 30. NCP1402SN19T1 Switch-on
Resistance vs. Temperature
TEMPERATURE (°C)
VLXLIM, VLX VOLTAGE LIMIT (V)
Figure 31. NCP1402SN30T1 Switch-on
Resistance vs. Temperature
TEMPERATURE (°C)
Figure 32. NCP1402SN50T1 Switch-on
Resistance vs. Temperature
TEMPERATURE (°C)
RDS(on), SWITCH-ON RESISTANCE ()
1.0
1.5
3.0
2.0
1.0
3.5
4.0
TEMPERATURE (°C)
0.4
0.6
0.8
0.2
0.0
1.0
0.4
0.6
-50 250-25 50 75 100
-50 250-25 50 75 100 -50 250-25 50 75 100
-50 250-25 50 75 100 -50 250-25 50 75 100
RDS(on), SWITCH-ON RESISTANCE ()R
DS(on), SWITCH-ON RESISTANCE ()
2.0
3.0
2.5
1.0
1.5
0.5
0.0
2.0
NCP1402SN19T1
VOUT = 1.9 V x 0.96
VLX = 0.4 V
Open-Loop Test
NCP1402SN19T1
Open-Loop Test
NCP1402SN30T1
Open-Loop Test
NCP1402SN50T1
Open-Loop Test
NCP1402SN50T1
VOUT = 5.0 V x 0.96
VLX = 0.4 V
Open-Loop Test
NCP1402SN30T1
VOUT = 3.0 V x 0.96
VLX = 0.4 V
Open-Loop Test
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1.5
0.5
1.0
0.0
2.0
1.5
0.5
1.0
0.0
2.0
1.5
0.5
1.0
0.0
2.0
0.8
0.4
0.0
1.0
0.2
0.6
-50
0.8
50
0.4
25-25
Vstart/Vhold, STARTUP/HOLD VOLTAGE (V)
0.0
Figure 33. NCP1402SN19T1 Startup/Hold
Voltage vs. Temperature
Figure 34. NCP1402SN30T1 Startup/Hold
Voltage vs. Temperature
Figure 35. NCP1402SN50T1 Startup/Hold
Voltage vs. Temperature
Figure 36. NCP1402SN19T1 Startup/Hold
Voltage vs. Output Current
IO, OUTPUT CURRENT (mA)
Vstart/Vhold, STARTUP/HOLD VOLTAGE (V)
Figure 37. NCP1402SN30T1 Startup/Hold
Voltage vs. Output Current
1.0
040503020 6010 70
Vstart
NCP1402SN19T1
L = 22 H
COUT = 10 F
IO = 0 mA
TEMPERATURE (°C)
0.2
0.6
75 100
Figure 38. NCP1402SN50T1 Startup/Hold
Voltage vs. Output Current
0
Vhold
-50 5025-25
Vstart/Vhold, STARTUP/HOLD VOLTAGE (V)
Vstart
NCP1402SN30T1
L = 22 H
COUT = 10 F
IO = 0 mA
TEMPERATURE (°C)
75 1000
Vhold
-50
0.8
50
0.4
25-25
Vstart/Vhold, STARTUP/HOLD VOLTAGE (V)
0.0
1.0
Vstart
NCP1402SN50T1
L = 22 H
COUT = 10 F
IO = 0 mA
TEMPERATURE (°C)
0.2
0.6
75 1000
Vhold
Vstart
NCP1402SN19T1
L = 47 H
COUT = 68 F
TA = 25°C
Vhold
80 90 100
IO, OUTPUT CURRENT (mA)
Vstart/Vhold, STARTUP/HOLD VOLTAGE (V)
040503020 6010 70
Vstart
Vhold
80 90 100
IO, OUTPUT CURRENT (mA)
Vstart/Vhold, STARTUP/HOLD VOLTAGE (V)
040503020 6010 70
Vstart
Vhold
80 90 100
NCP1402SN50T1
L = 47 H
COUT = 68 F
TA = 25°C
NCP1402SN30T1
L = 47 H
COUT = 68 F
TA = 25°C
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Figure 39. NCP1402SN19T1 Operating
Waveforms (Medium Load)
Figure 40. NCP1402SN19T1 Operating
Waveforms (Heavy Load)
Figure 41. NCP1402SN30T1 Operating
Waveforms (Medium Load)
Figure 42. NCP1402SN30T1 Operating
Waveforms (Heavy Load)
Figure 43. NCP1402SN50T1 Operating
Waveforms (Medium Load)
Figure 44. NCP1402SN50T1 Operating
Waveforms (Heavy Load)
VOUT = 1.9 V, Vin = 1.2 V, IO = 30 mA, L = 47 H, COUT = 68 F
1. VLX, 1.0 V/div
2. VOUT
, 20 mV/div, AC coupled
3. IL, 100 mA/div
2 s/div
VOUT = 3.0 V, Vin = 1.2 V, IO = 30 mA, L = 47 H, COUT = 68 F
1. VLX, 2.0 V/div
2. VOUT
, 20 mV/div, AC coupled
3. IL, 100 mA/div
5 s/div
VOUT = 3.0 V, Vin = 1.2 V, IO = 70 mA, L = 47 H, COUT = 68 F
1. VLX, 2.0 V/div
2. VOUT
, 20 mV/div, AC coupled
3. IL, 100 mA/div
VOUT = 1.9 V, Vin = 1.2 V, IO = 70 mA, L = 47 H, COUT = 68 F
1. VLX, 1.0 V/div
2. VOUT
, 20 mV/div, AC coupled
3. IL, 100 mA/div
5 s/div
2 s/div
2 s/div
VOUT = 5.0 V, Vin = 1.5 V, IO = 30 mA, L = 47 H, COUT = 68 F
1. VLX, 2.0 V/div
2. VOUT
, 20 mV/div, AC coupled
3. IL, 100 mA/div
2 s/div
VOUT = 5.0 V, Vin = 1.5 V, IO = 60 mA, L = 47 H, COUT = 68 F
1. VLX, 2.0 V/div
2. VOUT
, 20 mV/div, AC coupled
3. IL, 100 mA/div
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Figure 45. NCP1402SN19T1 Load Transient
Response
Figure 46. NCP1402SN19T1 Load Transient
Response
Figure 47. NCP1402SN30T1 Load Transient
Response
Figure 48. NCP1402SN30T1 Load Transient
Response
Figure 49. NCP1402SN50T1 Load Transient
Response
Figure 50. NCP1402SN50T1 Load Transient
Response
Vin = 1.2 V, L = 47 H, COUT = 68 F
1. VOUT = 1.9 V (AC coupled), 100 mV/div
2. IO = 0.1 mA to 80 mA
Vin = 1.2 V, L = 47 H, COUT = 68 F
1. VOUT = 1.9 V (AC coupled), 100 mV/div
2. IO = 80 mA to 0.1 mA
Vin = 2.4 V, L = 47 H, COUT = 68 F
1. VOUT = 5.0 V (AC coupled), 100 mV/div
2. IO = 0.1 mA to 80 mA
Vin = 2.4 V, L = 47 H, COUT = 68 F
1. VOUT = 5.0 V (AC coupled), 100 mV/div
2. IO = 80 mA to 0.1 mA
Vin = 1.5 V, L = 47 H, COUT = 68 F
1. VOUT = 3.0 V (AC coupled), 100 mV/div
2. IO = 0.1 mA to 80 mA
Vin = 1.5 V, L = 47 H, COUT = 68 F
1. VOUT = 3.0 V (AC coupled), 100 mV/div
2. IO = 80 mA to 0.1 mA
NCP1402
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2.5
1.0
3.0
1.5
2.0
3.5
0
60
604020
Vripple, RIPPLE VOLTAGE (mV)
0
Figure 51. NCP1402SN19T1 Ripple Voltage vs.
Output Current
Figure 52. NCP1402SN30T1 Ripple Voltage vs.
Output Current
Figure 53. NCP1402SN50T1 Ripple Voltage vs.
Output Current
Figure 54. NCP1402SNXXT1 Operating
Current 1 vs. Output Voltage
VOUT
, OUTPUT VOLTAGE (V)
IDD1, OPERATING CURRENT 1 (mA)
Figure 55. NCP1402SNXXT1 Pin On-state
Current vs. Output Voltage
Figure 56. NCP1402SNXXT1 Switch-On
Resistance vs. Output Voltage
80
13425
Vin = 1.2 V
NCP1402SN19T1
L = 47 H
COUT = 68 F
TA = 25°C
85°C
IO, OUTPUT CURRENT (mA)
20
40
100
80 100 120 140 160 180 200
Vin = 0.9 V
Vin = 1.5 V
0
60
604020
Vripple, RIPPLE VOLTAGE (mV)
0
80
Vin = 1.2 V
NCP1402SN30T1
L = 47 H
COUT = 68 F
TA = 25°C
IO, OUTPUT CURRENT (mA)
20
40
100
80 100 120 140 160 180 20
0
Vin = 0.9 V Vin = 1.5 V
0
60
604020
Vripple, RIPPLE VOLTAGE (mV)
0
80
Vin = 1.2 V
NCP1402SN50T1
L = 47 H
COUT = 68 F
TA = 25°C
IO, OUTPUT CURRENT (mA)
20
40
100
80 100 120 140 160 180 200
Vin = 0.9 V
Vin = 1.5 V
Vin = 2.0 V
Vin = 2.5 V
Vin = 2.0 V
Vin = 3.0 V
Vin = 4.0 V
60
0
80
20
40
100
6
25°C
-40 °C
NCP1402SNXXT1
VOUT = VSET x 0.96
Open-loop Test
VOUT
, OUTPUT VOLTAGE (V)
RDS(ON), SWITCH-ON RESISTANCE ()
13425
85°C
6
25°C
-40 °C
NCP1402SNXXT1
VOUT = VSET x 0.96
VLX = 0.4 V
Open-loop Test
VOUT
, OUTPUT VOLTAGE (V)
ILX, LX PIN ON-STATE CURRENT (mA)
13425
85°C
220
100
260
140
180
300
6
25°C
-40 °C
NCP1402SNXXT1
VOUT = VSET x 0.96
VLX = 0.4 V
Open-loop Test
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300
200
0
400
0
125
321
Iin(no load), NO LOAD INPUT CURRENT (A)
0
Vin, INPUT VOLTAGE (V)
Figure 57. NCP1402SNXXT1 No Load Input
Current vs. Input Voltage
Figure 58. NCP1402SNXXT1 Maximum Output
Current vs. Input Voltage
IO(max), MAX. OUTPUT CURRENT (mA)
150
0
1.9 V
NCP1402SNXXT1
L = 47 H
IO = 0 mA
TA = 25°C
Vin, INPUT VOLTAGE (V)
25
50
75
100
45
100
6
2.7 V
3.0 V
3.3 V
5.0 V
1.9 V
2.7 V
3.0 V
3.3 V 5.0 V
NCP1402SNXXT1
L = 47 H
TA = 25°C
123 45
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 A
(VOUT = 1.9 V), and can be further reduced to about 0.6 A
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 startup 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 pullup 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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APPLICATIONS CIRCUIT INFORMATION
1
3
GND
CE
2
OUT
NC
4
LX
5
NCP1402
Figure 59. Typical Application Circuit
VOUT
C2
68 F
D1
L1
47 H
C1
10 F
Vin
Step-up Converter Design Equations
NCP1402 step-up DC-DC converter designed to operate
in continuous conduction mode can be defined by:
Calculation Equation
LvMǒVin2
VOUTIOmaxǓ
IPK (Vin *Vs)ton
L)Imin
Imin (ton )toff)IO
toff *(Vin *VS)ton
2L
toff
(Vin *Vs)ton
(VOUT )VF*Vin)
Q(IL*IO)toff
Vripple [Q
COUT )(IL*IO)ESR
*NOTES:
IPK - Peak inductor current
Imin - Minimum inductor current
IO- Desired dc output current
IOmax - Desired maximum dc output current
IL- Average inductor current
Vin - Nominal operating dc input voltage
VOUT - Desired dc output voltage
VF- Diode forward voltage
VS- Saturation voltage of the internal FET switch
Q - Charge stores in the COUT during charging up
Vripple - Output ripple voltage
ESR - Equivalent series resistance of the output capacitor
M - 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 H
inductor in most applications. 47 H 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 H 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
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 Equivalent Series Resistance (ESR) Tantalum or
ceramic capacitor with value of 10 F should be suitable.
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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 to 0.30 ) 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
20 mm
Figure 60. NCP1402 PFM Step-Up DC-DC Converter Evaluation Board Silkscreen
Figure 61. NCP1402 PFM Step-Up DC-DC Converter Evaluation Board Artwork (Component Side)
23 mm
23 mm
NCP1402
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Components Supplier
Parts Supplier Part Number Description Phone
Inductor, L1 Sumida Electric Co. Ltd. CD54-470L Inductor 47 H / 0.72 A (852)-2880-6688
Schottky Diode, D1 ON Semiconductor Corp. MBR0520LT1 Schottky Power Rectifier (852)-2689-0088
Output Capacitor, C2 KEMET Electronics Corp. T494D686K010AS Low ESR Tantalum Capacitor
68 F / 10 V (852)-2305-1 168
Input Capacitor, C1 KEMET Electronics Corp. T491C106K016AS Low Profile Tantalum Capacitor
10 F / 16 V (852)-2305-1 168
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.
1
3
GND
CE
2
OUT
NC
6
LX
5
NCP1402
On
TP1
TP4
TP2
TP3
Vin
GND
Vout
GND
C2
68 F/10 V
L1
47 H
JP1
Enable
C1
10 F/16 V Off
D1
MBR0520LT1
Figure 62. NCP1402 Evaluation Board Schematic Diagram
++
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ORDERING INFORMATION
Device Output Voltage Device Marking Package Shipping†
NCP1402SN19T1 1.9 V DAU SOT23-5
3000 Units Per Reel
NCP1402SN19T1G 1.9 V DAU SOT23-5
(Pb-Free)
NCP1402SN27T1 2.7 V DAE SOT23-5
NCP1402SN27T1G 2.7 V DAE SOT23-5
(Pb-Free)
NCP1402SN30T1 3.0 V DAF SOT23-5
NCP1402SN30T1G 3.0 V DAF SOT23-5
(Pb-Free)
NCP1402SN33T1 3.3 V DAG SOT23-5
NCP1402SN33T1G 3.3 V DAG SOT23-5
(Pb-Free)
NCP1402SN40T1 4.0 V DCR SOT23-5
NCP1402SN40T1G 4.0 V DCR SOT23-5
(Pb-Free)
NCP1402SN50T1 5.0 V DAH SOT23-5
NCP1402SN50T1G 5.0 V DAH SOT23-5
(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.
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.
NCP1402
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PACKAGE DIMENSIONS
SOT23-5
(TSOP-5, SC59-5)
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.
NCP1402/D
The product described herein (NCP1402), may be covered by the following U.S. patents: 6,518,834. There may be other patents pending.
PUBLICATION ORDERING INFORMATION
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