AP1506
150KHz, 3A PWM BUCK DC/DC CONVERTER
AP1506
Document number: DS31015 Rev. 7 - 2 1 of 14
www.diodes.com June 2010
© Diodes Incorporated
Description
The AP1506 series are monolithic IC designed for a step-
down DC/DC converter, and own the ability of driving a 3A
load without external transistor. Due to reducing the number
of external components, the board space c an be save d easil y.
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 to prevent over
current operating of the o utput switch. If current limit function
occurred and VFB is down to 0.5V below, the switching
frequency will be reduced. The AP1506 series operate 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 conditions, and +15% on the
oscillator frequency. The output version included fixed 3.3V,
5V, 12V, and an adjustable type. The packages are available
in a standard 5-lead TO263 and TO220.
Features
• Output Voltage: 3.3V, 5V, 12V and Adjustable Output
Version
• Adjustable Version Output Voltage Range, 1.23V to
18V+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 22V
• Output Load Current: 3A
• Lead Free packages: TO263-5L and TO220-5L(R)
• TO263-5L and TO 220-5L(R): Available in “Green”
Molding Compound (No Br, Sb)
• Low Power standby mode
• Built-in Switching Transistor On Chip
• Lead Free Finish/RoHS Compliant (Note 1)
Pin Assignments
( Top View )
1 VIN
5 SD
4 FB
3 Gnd
2 Output
Metal Tab GND
TO263-5L
1 VIN
5 SD
4 FB
3 Gnd
2 Output
( Top View )
TO220-5L/TO220-5L(R)
Applications
• Simple High-Efficiency Step-Down Regulator
• On-Card Switching Regulators
• Positive to Negative Converter
Notes: 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at
http://www.diodes.com/products/lead_free.html.
AP1506
150KHz, 3A PWM BUCK DC/DC CONVERTER
AP1506
Document number: DS31015 Rev. 7 - 2 2 of 14
www.diodes.com June 2010
© Diodes Incorporated
Typical Application Circuit
(1) Fixed Type Circuit
12
3
5
4
12V
DC Input
CIN
Capacitor
FB
SD D1*
Schottky Diode
VIN
GND
Output
AP1506
-33
Co
Capacitor
Inductor
L1
33uH 3.3V/3A
Output Load
(2) Adjustable Type Circuit
12
35
4
12V
DC Input
CIN
Capacitor
FB
SD D1*
Schottky Diode
VIN
GND
Output
AP1506
Co
Capacitor
L1
47uH 5V/ 3A
Output Load
R2 R1
Vout = VFB
×
(1 + R2
R1 )
VFB = 1.23V
R2 = 1K ~ 3K
(3) Delay Start Circuit
12
3
5
4
12V
DC Input
CIN
Capacitor
FB
SD D1*
Schottky Diode
VIN
GND
Output
AP1506
Co
Capacitor
L1
47uH 5V / 3A
Output Load
R2 R1
C
DELAY
0.1uF
10K
RDELAY
Notes: 2. For up to 2A = DFLS230L (Vf = 0.42V)
For up to 3A = B340LA, B340LB (Vf = 0.45V)
AP1506
150KHz, 3A PWM BUCK DC/DC CONVERTER
AP1506
Document number: DS31015 Rev. 7 - 2 3 of 14
www.diodes.com June 2010
© Diodes Incorporated
Pin Descriptions
Functional Block Diagram
Current
Source
bias
1.235V
Reference
2.5V
Regulator
150KHz
OSC.
Start
up
+
-
Thermal
Shutdown
Pre-driver
Comp
GND
Output
SD
FB
220mV
200mV
3A
Switch
Frequecy
compen-
sation
+
-
Comp
+
-
Comp
+
-
Amp
VIN
Pin Name Description
VIN Operating Voltage Input
Output Switching Output
GND Ground
FB Output Voltage Feedback Control
SD ON/OFF Shutdown
AP1506
150KHz, 3A PWM BUCK DC/DC CONVERTER
AP1506
Document number: DS31015 Rev. 7 - 2 4 of 14
www.diodes.com June 2010
© Diodes Incorporated
Absolute Maximum Ratings
Symbol Parameter Rating Unit
ESD MM Machine Model ESD Protection 400 V
VCC Supply Voltage +24 V
VSD ON/OFF Pin Input Voltage -0.3 to +18 V
VFB Feedback Pin Voltage -0.3 to +18 V
VOUT Output Voltage to Ground -1 V
PD Power Dissip ation Internally Limited W
TST Storage Temperature -65 to +150 oC
TOP Operating Junction Temperature -40 to +125 oC
Recommended Operating Conditions
Symbol Parameter Min Max Unit
VOP Operating Voltage 4.5 22 V
TA Operating Ambient Temperature -20 85 oC
AP1506
150KHz, 3A PWM BUCK DC/DC CONVERTER
AP1506
Document number: DS31015 Rev. 7 - 2 5 of 14
www.diodes.com June 2010
© Diodes Incorporated
Electrical Characteristics (All Output Voltage Versions)
Unless otherwise specified, VIN = 12V for 3.3V, 5V, adjustable version and VIN = 18V 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) - -10
-50 nA
-100
FOSC Oscillator Frequency 127 150 173
KHz
110 - 173
FSCP Oscillator Frequency of
Short Circuit Protect When current limit occurred
and VFB < 0.5V, Ta = 25 oC 10 30 50 KHz
VSAT Saturation Voltage IOUT = 3A
No outside circuit
VFB = 0V force driver on - 1.4
1.6 V
1.7
DC Max. Duty Cycle (ON) VFB = 0V force driver on - 100 - %
Min. Duty Cycle (OFF) VFB = 12V force drive r off - 0 -
ICL Current Limit Peak current
No outside circuit
VFB = 0 force driver on 3.6 4.5 5.5 A
6.5
IL Output = 0V Output
Leakage
Current
No outside circuit
VFB = 12 force driver off - - -200
µA
Output = -1V VIN = 22V - -5 - mA
IQ Quiescent Current VFB = 12 force driver off - 5 10 mA
ISTBY Standby Quiescent
Current ON/OFF pin = 5V
VIN = 22V - 70
150 µA
200
VIL ON/OFF Pin Logic Input
Threshold 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 (OFF) - - -0.01 µA
IL ON/OFF Pin Input
Current VLOGIC = 0.5V (ON) - -0.1 -1
θJA Thermal Resistance
Junction to Ambient TO263-5L (Note 3) 37 - oC/W
TO220-5L(R) (Note 3) 31 -
θJC Thermal Resistance
Junction to Case TO263 -5L (Note 3) 6 - oC/W
TO220-5L(R) (Note 3) 5 -
Notes: 3. Test condition: Device mounted with copper area of approximately 3 in2, no air flow.
AP1506
150KHz, 3A PWM BUCK DC/DC CONVERTER
AP1506
Document number: DS31015 Rev. 7 - 2 6 of 14
www.diodes.com June 2010
© 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 VMin Typ. VMax Unit
AP1506-ADJ FB
V Output
Feedback
5V < VIN < 22V
0.2A < ILOAD < 3A
VOUT programmed for
3V
1.193 1.23 1.267 V
1.18 - 1.28
η Efficiency VIN = 12V, ILOAD = 3A - 74 - %
AP1506-3.3V OUT
V Output
Voltage 5.5V < VIN < 22V
0.2A < ILOAD < 3A 3.168 3.3 3.432 V
3.135 - 3.465
η Efficiency VIN = 12V, ILOAD = 3A - 75 - %
AP1506-5V OUT
V Output
Voltage 8V < VIN < 22V
0.2A < ILOAD < 3A 4.8 5 5.2 V
4.75 - 5.25
η Efficiency VIN = 12V, ILOAD = 3A - 80 - %
AP1506-12V OUT
V Output
Voltage 15V < VIN < 22V
0.2A < ILOAD < 3A 11.52 12 12.48 V
11.4 - 12.6
η Efficiency VIN = 16V, ILOAD = 3A - 89 - %
AP1506
150KHz, 3A PWM BUCK DC/DC CONVERTER
AP1506
Document number: DS31015 Rev. 7 - 2 7 of 14
www.diodes.com June 2010
© 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
presented at this pin to minimize voltage transients and to supply the switching currents needed by the reg ulator.
Ground
Circuit ground.
Output
Internal switch. The voltage at this pin switches between (+VIN – VSAT) and approximately – 0.5V, with a duty cycle
of approximately VOUT / VIN. To minimize coupling to sensitive circuitry, the PC board copper area connected to
this pin should be kept to a minimum.
Feedback (FB)
Senses the regulated output voltage to complete the feedback loo p.
ON/OFF (SD)
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 18V) shuts the regulator down. If this shutdown
feature is not needed, the ON / OFF pin can be wire d to the ground pin.
Thermal Considerations
The AP1506 is available in two packages: a 5-pin TO220 and a 5 -pin surface mount TO263.
The TO220 package needs a heat sink under most conditions. The size of the heat sink depends on the input
voltage, the output voltage, the load current and the ambient temperature. The AP1506 junction temperature rises
above ambient temperature for a 3A load and different input and output voltages. The data for these curves was
taken with the AP1506 (TO220 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 temperature s re quire more heat sinking.
The TO263 surface mount package tab was designed to be soldering to the copper on a printed circuit board. The
copper 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 side d, multi-layer PC board with large
copper areas and/or airflow will be recommended.
AP1506
150KHz, 3A PWM BUCK DC/DC CONVERTER
AP1506
Document number: DS31015 Rev. 7 - 2 8 of 14
www.diodes.com June 2010
© Diodes Incorporated
Functional Description (Continued)
The AP1506 (TO263 package) junction temperature rises above ambient temperature with a 2A load for various
input and output voltages. 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 actual operating conditions. This
curve can be used for a quick check for the approximate junction temperature for various conditions, but be aware
that there are many factors that can affect the junction temperature. When load currents higher than 3A are used,
double sided or multi-layer PC boards with large copper areas and/or airflow might be needed, especially for high
ambient temperatures and high output voltages.
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 thermal resistance even further.
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 even board temperature. Other factors are: trace width, total printed circuit copper area, copper
thickness, single or double-sided, multi-layer board and the amount of solder on the board. The effectiveness of
the PC board to dissipate heat also depends on the size, quantity and spacing of other components 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,
depending on the physical size, type of core material and the DC resistance, it could either act as a heat sink
taking heat away from the board, or it could add heat to the board.
AP1506
150KHz, 3A PWM BUCK DC/DC CONVERTER
AP1506
Document number: DS31015 Rev. 7 - 2 9 of 14
www.diodes.com June 2010
© Diodes Incorporated
Typical Performance Characteristics
AP1506 Efficiency vs. Temperature
(VIN = 12V, VOUT = 5V, Io = 3A)
72
73
74
75
76
77
78
79
80
81
82
83
-50 -30 -10 10 30 50 70 90 110 130 150
Temperature (TA)
Efficiency (%)
AP1506 Efficiency vs. Temperature
(VIN = 12V, VOUT = 3.3V, Io = 3A)
70
71
72
73
74
75
76
77
78
-50 -30 -10 10 30 50 70 90 110 130 150
T emperature (TA) (oC)
Eff iciency (%)
AP1506 Saturation Voltage vs. Temperature
(Vcc = 12V, VFB = 0V, VSD = 0)
0.7
0.8
0.9
1
1.1
1.2
1.3
1.4
1.5
1.6
-50 -25 0 25 50 75 100 125
Temperature (TA) (oC)
Saturation Voltage (V)
3A
2A
1A
0.5A
AP1506 S witch Current L i mit vs. Temperature
(Vcc = 12V, VFB = 0V)
3
3.5
4
4.5
5
5.5
-50-30-101030507090
Temperature (TA) (oC)
Switch Current Limit (A)
AP1506 Supply Current vs. Temperature
(Vcc = 12V, No Load, Von
/
of
f
= 0V (Switch ON), Von/of
f
= 5V (Switch OFF))
5
6
7
8
9
10
11
12
13
14
15
-50 -30 -10 10 30 50 70 90 110 130 150
Temperature (TA) (oC)
Supply Current (mA)
Switch ON
30
35
40
45
50
55
60
-50 -30 -10 10 30 50 70 90 110 130 150
Temperature (TA) (oC)
Supply Current (uA)
Switch OFF
AP1506
150KHz, 3A PWM BUCK DC/DC CONVERTER
AP1506
Document number: DS31015 Rev. 7 - 2 10 of 14
www.diodes.com June 2010
© Diodes Incorporated
Typical Performance Characteristics (Continued)
AP1506 Threshold Voltage vs. Temperature
(Vcc = 12V, Io = 100mA)
0.8
0.9
1
1.1
1.2
1.3
1.4
1.5
1.6
1.7
-50 -30 -10 10 30 50 70 90 110 130 150
Temperature (TA) (oC)
Threshold Voltage (V)
AP1506 ON/OFF Current vs. ON/OFF Voltage
(VIN = 12V)
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
10
036912151821
ON/OFF Voltage (V )
ON/OFF Current (nA)
AP1506 Frequency v s. Temperature
(Vcc = 12V, Ic = 500mA, VOUT = 5V)
140
145
150
155
160
165
170
-50 -30 -10 10 30 50 70 90 110 130 150
Temperature (TA) (oC)
Frequency (KHz)
AP1506 Feedback Current vs. Temperature
(Vcc = 12V, VOUT = 5V, VFB = 1.3V)
-50
-40
-30
-20
-10
0
10
-50 -30 -10 10 30 50 70 90 110 130 150
Temperature (TA) (oC)
Feedback Current (nA)
AP1506 Output Voltage vs. Temperature
(VIN = 12V, Io = 3A)
2.9
2.95
3
3.05
3.1
3.15
3.2
3.25
3.3
3.35
3.4
3.45
3.5
-40 -20 0 20 40 60 80 100 120 140 160
Temperature (TA) (oC)
Vout (V)
AP1506
150KHz, 3A PWM BUCK DC/DC CONVERTER
AP1506
Document number: DS31015 Rev. 7 - 2 11 of 14
www.diodes.com June 2010
© Diodes Incorporated
Ordering Information
Package
K5 : TO263- 5L
Output version
AP1506 - 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 4)
Tube/Bulk 13” Tape and Reel
Quantity Part Number
Suffix Quantity Part Number
Suffix
AP1506-XXK5L-13 K5 TO263-5L NA NA 800/Tape & Reel -13
AP1506-XXK5G-13 K5 TO263-5L NA NA 800/Tape & Reel -13
AP1506-XXT5L-U T5 TO220-5L 50 -U NA NA
AP1506-XXT5G-U T5 TO220-5L 50 -U NA NA
AP1506-XXT5RL-U T5R TO220-5L(R) 50 -U NA NA
AP1506-XXT5RG-U T5R TO220-5L(R) 50 -U NA NA
Notes: 4. 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.
AP1506
150KHz, 3A PWM BUCK DC/DC CONVERTER
AP1506
Document number: DS31015 Rev. 7 - 2 12 of 14
www.diodes.com June 2010
© Diodes Incorporated
Marking Information
(1) TO263-5L
1506-XX
Output Type:
1506 : ADJ
1506-33 : 3.3V
1506-50 : 5.0V
1506-12 : 12V
Logo
ID code
Year:
( Top view )
"08" = 2008
"07" = 2007
YY WW X X
Xth week: 01~52
~
L : Lead Free
G : Green
(2) TO220-5L(R)
1506-XX
Output Type:
1506 : ADJ
1506-33 : 3.3V
1506-50 : 5.0V
1506-12 : 12V
Logo
ID code
Year: "08" = 2008
"07" = 2007
YY WW X XXth week: 01~52
~
L : Lead Free
G : Green
( Top view )
AP1506
150KHz, 3A PWM BUCK DC/DC CONVERTER
AP1506
Document number: DS31015 Rev. 7 - 2 14 of 14
www.diodes.com June 2010
© Diodes Incorporated
IMPORTANT NOTICE
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DOCUMENT, INCLUDING, BUT N OT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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changes without further notice to this document and any product described herein. Diodes Incorporat ed does not assume an y liability
arising out of the application or use of this docum ent or any product described herein; neither does Diodes Incorporated convey an y
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Diodes Incorporated products are specifically not authorized for use as critical components in life support devic es or systems without
the express written approval of the Chief Executive Officer of Diodes Incorporated. As used herein:
A. Life support devices or systems are devices or systems which:
1. are intended to implant into the body, or
2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided
in the labeling can be reasonably expected to result in significant injury to the user.
B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected
to cause the failure of the life support device or to affect its safety or effectiveness.
Customers represent that they ha ve all necessary expertise in the safety and regulatory ramifications of their life support dev ices or
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