AP1501A
150KHz , 5A P W M BUCK DC / D C CO N V E RT E R
AP1501A Rev. 10 1 of 14 SEPTEMBER 2009
DS31191 www.diodes.com © Diodes Incorporated
• Output voltage: 3.3V, 5V, 12V and adjustable output
version
• Adjustabl e vers i o n outp ut vo lt ag e r an ge , 1.23 V to
37V+4%
• 150Khz +15% fixed switching frequency
• Voltage mode non-synchronous PWM control
• Thermal-shutdown and current-limit protection
• ON/OFF shutdown control input
• Operating voltage can be up to 40V
• Output load current: 5A
• Low power stand by mode
• Built-in switching transistor on chip
• Lead Free packages: TO263-5L and TO220-5L(R)
• TO263-5L and TO220-5L(R): Available in “Green”
Molding Compound (No Br, Sb)
• Lead Free Finish/ RoHS Compliant (Note 1)
The AP1501A series are monolithic ICs that are designed for a
step-down DC/DC converter, and possess the ability to drive a
5A load without additional transistor component. Due to reducing
the number of external component, the board space can be
saved easily. The external shutdown function can be controlled
by logic level and then come into standby mode. The internal
compensation makes feedback control have good line and load
regulation without external design. Regarding protected function,
thermal shutdown is to prevent over temperature operating from
damage, and current limit is against over current operating of the
output switch. The AP1501A series operates at a switching
frequency of 150Khz thus allowing smaller sized filter
components than what would be needed with lower frequency
switching regulators. Other features include a guaranteed
+4% tolerance on output voltage under specified input voltage
and output load con ditions, and +15% on the oscilla tor frequency .
The output version includes fixed 3.3V, 5V, 12V, and an
adjustable type. The packages are available in a standard 5-lead
TO263 and TO220 packages.
• Simple High-efficiency step-down regulator
• On-card switching regulators
• Positive to negative converter
Typical Application Circuit
(1) Fixed Type Circuit
12
35
4
12V
DC Input
Cin
Capacitor
FB
SD D1
Schottky
Diode
Vin
Gnd
Output
AP1501A
-33
Co
Capacitor
Inductor
L1
18uH 3.3V/5A
Output Load
Features General Description
Applications
AP1501A
150KHz , 5A P W M BUCK DC / D C CO N V E RT E R
AP1501A Rev. 10 2 of 14 SEPTEMBER 2009
DS31191 www.diodes.com © Diodes Incorporated
Typical Application Circuit (Continued)
(2) Adjustable Type Circuit
12
35
4
12V
DC Input
Cin
Capacitor
FB
SD D1
Schottky Diode
Vin
Gnd
Output
AP1501A
Co
Capacitor
L1
22uH 5V/ 5A
Output Load
R2 R1
Vout = VFB
×
(1 + R2
R1 )
VFB = 1.23V
R2 = 1K ~ 3K
(3) Delay Start Circuit
12
35
4
12V
DC Input
Cin
Capacitor
FB
SD D1
Schottky D iode
Vin
Gnd
Output
AP1501A
Co
Capacitor
L1
22uH 5V/ 5A
Ou tpu t L o ad
R2 R1
CDELAY
0.1uF
10K
RDELAY
AP1501A
150KHz , 5A P W M BUCK DC / D C CO N V E RT E R
AP1501A Rev. 10 3 of 14 SEPTEMBER 2009
DS31191 www.diodes.com © Diodes Incorporated
Lead-free
Lead-free
Lead-free
Lead-free
Package
K5 : TO263-5L
Output Version
AP1501A - XX XXX X - X
Packing
U : Tube
13 : Tape & Reel
Blank : Adjustable
33 : 3.3V
50 : 5.0V
12 : 12V
Lead Free
L : Lead Free
T5 : TO220-5L
T5R : TO220-5L(R)
G : Green
Device Package
Code Packaging
(Note 2)
Tube 13” Tape and Reel
Quantity Part Number
Suffix Quantity Part Number
Suffix
AP1501A-XXK5L-U K5 TO263-5L 50 -U NA NA
AP1501A-XXK5L-13 K5 TO263-5L NA NA 800/Tape & Reel -13
AP1501A-XXK5G-U K5 TO263-5L 50 -U NA NA
AP1501A-XXK5G-13 K5 TO263-5L NA NA 800/Tape & Reel -13
AP1501A-XXT5L-U T5 TO220-5L 50 -U NA NA
AP1501A-XXT5G-U T5 TO220-5L 50 -U NA NA
AP1501A-XXT5RL-U T5R TO220-5L(R) 50 -U NA NA
AP1501A-XXT5RG-U T5R TO220-5L(R) 50 -U NA NA
Notes: 1. EU Dire ctive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at
http://www.diodes.com/products/lead_free.html
2. Pad layout as shown on Diodes Inc. suggested pad layout document AP02001, which can be found on our website at
http://www.diodes.com/datasheets/ap02001.pdf.
Pin Assignments
( Top View )
1 VIN
5 SD
4 FB
3 Gnd
2 Output
Met al T ab GND
TO263-5L
1 VIN
5 SD
4 FB
3 Gnd
2 Output
( Top View )
TO220-5L/TO220-5L(R)
Ordering Information
AP1501A
150KHz , 5A P W M BUCK DC / D C CO N V E RT E R
AP1501A Rev. 10 4 of 14 SEPTEMBER 2009
DS31191 www.diodes.com © Diodes Incorporated
Pin Descriptions
Current
Source
bias
1.235V
Reference
2.5V
Regulator
150kHz
OSC.
Start
up
+
+
_
+
_
Thermal
Shutdown
Pre-driver
Comp
Comp
Gnd
Output
VIN
SD
FB
220mV200mV
5A
Switch
+
_
_
Amp
Comp
Freq.
Compensation
Name Description
VIN Operating voltage input
Output Switching output
Gnd Ground
FB Output voltage feedback control
SD ON/OFF shutdown
Block Diagram
AP1501A
150KHz , 5A P W M BUCK DC / D C CO N V E RT E R
AP1501A Rev. 10 5 of 14 SEPTEMBER 2009
DS31191 www.diodes.com © Diodes Incorporated
Absolute Maximum Ratings
Symbol Parameter Rating Unit
ESD MM Machine Model ESD Protection 400 V
VCC Supply Voltage +45 V
VSD ON/OFF Pin input voltage -0.3 to +40 V
VFB Feedback Pin voltage -0.3 to +40 V
VOUT Output voltage to Ground -1 V
PD Power dissipation Internally limited W
TST Storage temperature -65 to +150 oC
TJ Operating Junction Temperature -20 to +125 oC
Recommended Operating Conditions
Symbol Parameter Rating Units
VOP Operating v oltage 4.5 to 40 V
TA Operat ing Ambient Temp erature -20 to 85 oC
AP1501A
150KHz , 5A P W M BUCK DC / D C CO N V E RT E R
AP1501A Rev. 10 6 of 14 SEPTEMBER 2009
DS31191 www.diodes.com © Diodes Incorporated
Electrical Characteristics ( All Output Voltage Versions )
Unless otherwise specified, VIN = 12V for 3.3V, 5V, adjustable version and VIN = 24V for the 12V version. ILOAD = 0.5A
Specifications with boldface type are for full operating temperature range, the other type are for TJ = 25ºC.
Symbol Parameter Conditions Min Typ. Max Unit
IFB Feedback Bias Current
VFB = 1.3V
(Adjustable version only) 40
60 nA
100
FOSC Oscillator Frequency 127 150 173 Khz
110 173
VSAT Saturation Voltage IOUT = 5A
no outside circuit
VFB = 0V force driver on 1.5
1.6 V
1.7
DC Max. Duty Cycle(ON) VFB = 0V force driver on 100 %
Min. Duty Cycle(OFF) VFB = 12V forc e dr i v er of f 0
ICL Current Limit peak curre nt
no outside circuit
VFB = 0 forc e driver on 5.5 6.0 6.5 A
7.5
IL Output = 0V Output
Leakage
Current
no outside circuit
VFB = 12 force driver off (Note 3) 200 uA
Output = -1V VIN = 40V 2 60 mA
IQ Quiescent Current VFB = 12 force driver off 5 10 mA
ISTBY Standby Quiescent
Current ON/OFF pin = 5V
VIN = 40V 150
250 uA
300
VIL ON/OFF Pin Logic Input
Thres h old Voltage
Low (regulator ON) 1.3 0.6 V
VIH High (regulator OFF) 2.0
IH ON/OFF Pin Logic
Input Current VLOGIC = 2.5V (O F F ) 15 25 uA
IL ON/OFF Pin Input
Current VLOGIC = 0.5V (ON) 0.02 5
θJA Thermal Resistance
Junction-to-Ambient
TO263-5L (Note 4) 37 oC/W
TO220-5L(R) (Note 4) 31
θJC Thermal Resistance
Junction-to-Case
TO263-5L (Note 4) 6
oC/W
TO220-5L(R) (Note 4) 5
Notes: 3. Feedback pin removed from output and connected to 0V to force the output transistor switch ON. Feedback pin removed from output
and connected to 12V for the 3.3V, 5V, and the ADJ. version, and 15V for the 12V version, to force the output transistor s witch OFF.
4. Test condition: Device mounted with copper area of approximately 3in2, 1oz, no air flow.
AP1501A
150KHz , 5A P W M BUCK DC / D C CO N V E RT E R
AP1501A Rev. 10 7 of 14 SEPTEMBER 2009
DS31191 www.diodes.com © Diodes Incorporated
Electrical Characteristics ( Continued )
Specifications with boldface type are for full operating temperature range, the other type are for TJ = 25ºC.
Symbol Parameter Conditions Typ. Limit Unit
AP1501A-ADJ FB
V Output
Feedback
5V < VIN < 40V
0.2A < ILOAD < 5A
VOUT programmed for 3V 1.23 1.193/1.18
1.267/1.28
V
VMIN
VMAX
η Efficiency VIN = 12V, ILOAD=5A 72 %
AP1501A-3.3V OUT
V Output V oltage 5.5V < VIN < 40V
0.2A < ILOAD < 5A 3.3 3.168/3.135
3.432/3.465
V
VMIN
VMAX
η Efficiency VIN = 12V, ILOAD=5A 71 %
AP1501A-5V OUT
V Output V oltage 8V < VIN < 40V
0.2A < ILOAD < 5A 5 4.8/4.75
5.2/5.25
V
VMIN
VMAX
η Efficiency VIN = 12V, ILOAD = 5A 78 %
AP1501A-12V OUT
V Output Voltage 15V < VIN < 40V
0.2A < ILOAD < 5A 12 11.52/11.4
12.48/12.6
V
VMIN
VMAX
η Efficiency VIN = 16V, ILOAD = 5A 88 %
AP1501A
150KHz , 5A P W M BUCK DC / D C CO N V E RT E R
AP1501A Rev. 10 8 of 14 SEPTEMBER 2009
DS31191 www.diodes.com © Diodes Incorporated
Typical Performance Characteristics
Typical Perfor mance Ch aracteristi cs
Normalized Outpu t Vo l tag e
4.90
4.95
5.00
5.05
5.10
-50 -25 0 25 50 75 100 125
OUTPUT VOLTAGE CHANGE
VIN =20V, ILOAD=3A
Normalized at TJ = 25°C
JUNCTIO N T E M P E RATURE(°C)
JUNCTION TEMPERATURE(°C)
SWITCH CURRENT LIMIT (A)
Switch Current Limit
0.0
5.0
10.0
15.0
20.0
25.0
-50 -25 0 25 50 75 100 125
JUNCTION TEMPERATURE(°C)
SUPPLY CURRENT (m A )
Operating Quiescent Current
INPUT VOLTAGE
EFFICIENCY (%)
Efficiency
100
65
70
75
80
85
90
95
810152025
30 35 40
5V
3.3V
5A Load
1.2
1.3
1.4
1.5
1.6
1.7
2.0 345
SWITCH CURRENT(A)
SATURATION VOLTAGE (V)
1
2
3
1 : -40oC
2 : 25oC
3 : 125oC
Switch Saturation Voltage
5.5
6.0
6.5
7.0
7.5
-50 -25 0 25 50 75 100 125
VIN =12V, V
OUT=5V
SUPPLY VOLTAGE (V)
CURRENT (uA)
0.0
40.0
80.0
120.0
160.0
200.0
Shutdown Quiescent Current
10 20 30 40
VON/OFF=5V
1 : -40oC
2 : 25 oC
3 : 125oC
1
3
2
Switch ON
Switch OFF
AP1501A
150KHz , 5A P W M BUCK DC / D C CO N V E RT E R
AP1501A Rev. 10 9 of 14 SEPTEMBER 2009
DS31191 www.diodes.com © Diodes Incorporated
Typical Performance Characteristics (Continued)
JUNCTION TEMPERATURE(
o
C)
BIAS CURRENT (nA)
Feedback Pin Bias Current
1.45 10152022232425
ON/OFF PIN VOLTAGE (V)
CURRENT (uA)
ON/OFF Pin Current (Sinking)
0.0
30.0
60.0
90.0
120.0
150.0
V
IN
=40V
-40
o
C T
J
125
o
C
≤≤
0.0
10.0
20.0
30.0
40.0
50.0
-50 -25 0 25 50 75 100 125
Adjustable Version Only
0.0
1.0
2.0
3.0
4.0
5.0
-50 -25 0 25 50 75 100 125
JUNCTION TEMPERATURE (
o
C)
SUPPLY VOLTAGE (V)
Minimum Operating Supply Voltage
V
OUT
=1.23V
I
LOAD
=120mA
JUNCTION TEMPERATURE (
o
C)
THRESHOLD VOLTAGE (V)
ON/OFF Threshold Voltage
0.0
1.0
2.0
3.0
4.0
5.0
-50 -25 025 50 75 100 125
Switch Frequency
JUNCTION TEMPERATURE (
o
C)
FREQUENCY (kHz)
0.0
50.0
100.0
150.0
200.0
-50 -25 0 25 50 75 100 125
AP1501A
150KHz , 5A P W M BUCK DC / D C CO N V E RT E R
AP1501A Rev. 10 10 of 14 SEPTEMBER 2009
DS31191 www.diodes.com © Diodes Incorporated
Functional Description
Pin Functions
+VIN
This is the positive input supply for the IC switching regulator. A suitable
input bypass capacitor must be present at this pin to minimize voltage
transients and to supply the switching currents needed by the regulator.
Ground
Circuit ground.
Output
Internal switch. The voltage at this pin switches between (+VIN – VSAT)
and approximately – 0.5V, w ith a duty cycle of approx imately
VOUT / VIN. To minimize coupling to sensitive circuitry, the PC board
copper area connected to this pin should be kept a minimum.
Feedback
Senses the regulat ed output voltage to comp lete the feedback loop.
ON/OFF
Allows the switching regulator circuit to be shutdown using logic level
signals thus dropping the total input supply current to approximately
150uA. Pulling this pin below a threshold voltage of approximately
1.3V turns the regulator on, and pulling this pin above 1.3V (up to a
maximum of 40V) shuts the regulator down. If this shutdown feature is
not needed, the ON/OFF pin can be wired to the ground pin or it can be
left open, in either case the regulator will be in the ON condition.
Thermal Considera tions
The AP1501A is available in two packages, a 5-pin surface mount
TO-263 and TO-220.
The TO-220 package ne eds a heat s ink under mo st conditions. The size
of the heat sink depends on the input voltage, the output voltage, the
load current and the ambient temperature. The AP1501A junction
temperature rises abov e ambient tempe rature for a 5A load and d ifferent
input and output voltages. The data for these curves was taken with th e
AP1501A (TO-220 package) operating as a buck switching regulator in
an ambient temperature of 25oC (still air). These temperature rise
numbers are all approximate and there are many factors that can affect
these temperatures. Higher ambient temperatures require more heat
sinking.
The TO-263 surface mount package tab is designed to be soldered to
the copper on a printed ci rcuit board. The coppe r and the board are the
heat sink for this package and the other heat producing components,
such as the catch diode and inductor. The PC board copper area that
the package is soldered to should be at least 0.8 in2, and ideally should
have 2 or more square inches of 2 oz. Additional copper area improves
the thermal characteristics, but with copper areas greater than
approximately 6 in2, only small improvements in heat dissipation are
realized. If further thermal improvements are needed, double sided,
multilayer PC boards with large copper areas and/or airflow are
recommended.
The AP1501A (TO-263 package) junction temperature rise above
ambient temperature with a 2A load for various input and output v oltages.
This data was taken with the circuit operating as a buck switching
regulator with all components mounted on a PC board to simulate the
junction temperature under actu al oper ating c onditions. This curve can
be used for a quick ch eck for the a pproximate j unction temp erature for
various conditions, but be aware that there are many factors that can
affect the junction tempe ratu re. When load currents higher than 3A are
used, double sided or multilayer PC boards with large copper areas
and/or airflow might be needed , especially for high ambi ent temperatures
and high output voltage s.
For the best thermal performance, wide copper traces and generous
amounts of printed circuit board copper should be used in the board
layout. (Once exception to this is the output (switch) pin, which should not
have large areas of copper.) Large areas of copper provide the best
transfer of heat (lower thermal resistance) to the surrounding air, and
moving air lowers the the rmal resistance even fu rther.
Package thermal resistance and junction temperature rise numbers are
all approximate, and there are many factors that will affect these
numbers. Some of these factors include board size, shape, thickness,
position, location , and ev en board temperature. Other factors are, trace
width, total printed circuit copper area, copper thickness, single or
double-sided, multilayer board and the amount of solder on the board.
The effectiveness of the PC board t o dissipate he at also depend s on the
size, quantity and spac ing of othe r com ponents on the board, as well as
whether the surrounding air is still or moving.
Furthermore, some of these components such as the catch diode will
add heat to the PC board and the heat can vary as the input voltage
changes. For the inductor, depen ding on the p hysical si ze, type of core
material and the DC resistance, it could either act as a heat sink taking
heat away from the boa rd, or it could add heat to the board.
AP1501A
150KHz , 5A P W M BUCK DC / D C CO N V E RT E R
AP1501A Rev. 10 11 of 14 SEPTEMBER 2009
DS31191 www.diodes.com © Diodes Incorporated
Marking Information
(1) TO263-5L
1501A XX
Output Type :
1501A : ADJ
1501A33 : 3.3V
1501A50 : 5.0V
1501A12 : 12V
Logo
ID code
Year :
( Top View )
"09" = 2009
"08" = 2008
YY WW X X
Xth week : 01~52
~
L : Lead Free
G : Green
(2) TO220-5L(R)
1501AXX
Output Type :
1501A : ADJ
1501A33 : 3.3V
1501A50 : 5.0V
1501A12 : 12V
Logo
ID code
Year: "09" = 2009
"08" = 2008
YY WW X XXth week: 01~52
~
L : Lead Free
( Top View )
G : Green
AP1501A
150KHz , 5A P W M BUCK DC / D C CO N V E RT E R
AP1501A Rev. 10 14 of 14 SEPTEMBER 2009
DS31191 www.diodes.com © Diodes Incorporated
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DOCUMENT, INCLUDI NG, BUT NOT LIMITE D TO, THE I MPLIED WARRANTIE S OF MERCHA NTABILITY AND FIT NESS FOR A
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Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other
changes without further notice to this document and any product described herein. Diodes Incorporated does not assume any
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and mark i ngs noted herein m ay also be covere d b y one or more Uni te d S tates, i nte rn ational or fo re i gn trademarks.
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