AP1506
150KHz, 3A PWM BUCK DC/DC CONVERTER
AP1506 Rev. 2 1 of 13 NOVEMBER 2006
www.diodes.com © Diodes Incorporated
Lead-free
Lead-free
Lead-free
• 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
• TO220-5L, TO263-5L Packages
• Low Power standby mode
• Built-in Switching Transistor On Chip
• Lead Free Finish/RoHS Compliant (Note 1)
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
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 to prevent over current operating of the output 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 TO-220 or a 5-lead TO-263.
• Simple High-Efficiency Step-Down Regulator
• On-Card Switching Regulators
• Positive to Negative Converter
Ordering Information
Package
T5: TO220-5L
K5: TO263-5L
Output Version
AP1506 XX X X X
Packing
-U : Tube
-13 : Taping
Blank : Adjustable
33 : 3.3V
50 : 5.0V
12 : 12V
T5R: TO220-5L(R)
Lead Free
L : Lead Free Package
Note: 1. RoHS revision 13.2.2003. Glass and High Temperature Solder Exemptions Applied, see EU Directive Annex Notes 5 and 7.
Note: 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.
Features General Description
Applications
Tube 13” Tape and Reel
Device (Note 2) Package
Code Packaging Quantity Part Number
Suffix Quantity Part Number
Suffix
AP1506-XXK5 K5 TO263-5L NA NA 800/Tape & Reel -13
AP1506-XXT5 T5 TO220-5L 50 -U NA NA
AP1506-XXT5R T5R TO220-5L(R) 50 -U NA NA
AP1506
150KHz, 3A PWM BUCK DC/DC CONVERTER
AP1506 Rev. 2 2 of 13 NOVEMBER 2006
www.diodes.com © Diodes Incorporated
TO220-5L
( Top View )
1 V
IN
5 SD
4 FB
3 GND
2 Output
( Top View )
TO263-5L
1 V
IN
5 SD
4 FB
3 GND
2 Output
Metal Tab GND
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 Assignments Pin Descriptions
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 Rev. 2 3 of 13 NOVEMBER 2006
www.diodes.com © Diodes Incorporated
Absolute Maximum Ratings
Symbol Parameter Rating Unit
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 Dissipation Internally Limited W
TST Storage Temperature -65 to +150 oC
TOP Operating Temperature -40 to +125 oC
VOP Operating Voltage +4.5 to +22 V
AP1506
150KHz, 3A PWM BUCK DC/DC CONVERTER
AP1506 Rev. 2 4 of 13 NOVEMBER 2006
www.diodes.com © 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
-50
IFB Feedback Bias Current VFB = 1.3V
(Adjustable version only) - -10
-100 nA
127 150 173
FOSC Oscillator Frequency 110 - 173 KHz
FSCP Oscillator Frequency of
Short Circuit Protect
When current limit occurred
and VFB < 0.5V, Ta = 25 oC 10 30 50 KHz
1.6
VSAT Saturation Voltage
IOUT = 3A
No outside circuit
VFB = 0V force driver on
- 1.4
1.7 V
Max. Duty Cycle (ON) VFB = 0V force driver on - 100 -
DC Min. Duty Cycle (OFF) VFB = 12V force driver off - 0 - %
5.5
ICL Current Limit
Peak current
No outside circuit
VFB = 0 force driver on
3.6 4.5 6.5 A
Output = 0V No outside circuit
VFB = 12 force driver off - - -200 UA
IL
Output = -1V
Output
Leakage
Current VIN = 22V - -5 - MA
IQ Quiescent Current VFB = 12 force driver off - 5 10 MA
150
ISTBY Standby Quiescent
Current ON /OFF pin = 5V
VIN = 22V - 70
200 UA
VIL Low (regulator ON) - 0.6
VIH
ON /OFF Pin Logic Input
Threshold Voltage High (regulator OFF) 2.0 1.3 - V
IH ON /OFF Pin Logic
Input Current VLOGIC = 2.5V (OFF) - - -0.01
IL ON /OFF Pin Input
Current VLOGIC = 0.5V (ON) - -0.1 -1
UA
TO220-5L - 2.5 -
θJC Thermal Resistance
Junction to Case TO263-5L - 3.5 -
oC/W
TO220-5L - 28 -
θJA Thermal Resistance
Junction to Ambient TO263-5L
with a copper
area of
approximately
3in2
- 23 -
oC/W
AP1506
150KHz, 3A PWM BUCK DC/DC CONVERTER
AP1506 Rev. 2 5 of 13 NOVEMBER 2006
www.diodes.com © Diodes Incorporated
Electrical Characteristics (Continued)
Specifications with boldface type are for full opera ting tem perat ur e range, the other type are for TJ = 25ºC.
Symbol Parameter Conditions VMin. Typ. VMax. Unit
1.193 1.23 1.267
FB
V Output
Feedback
5V < VIN < 22V
0.2A < ILOAD < 3A
VOUT programmed
for 3V 1.18 - 1.28
V
AP1506-ADJ
η Efficiency VIN = 12V, ILOAD =
3A - 74 - %
3.168 3.3 3.432
OUT
V Output
Voltage
5.5V < VIN < 22V
0.2A < ILOAD < 3A 3.135 - 3.465
V
AP1506-3.3V
η Efficiency VIN = 12V, ILOAD =
3A - 75 - %
4.8 5 5.2
OUT
V Output
Voltage
8V < VIN < 22V
0.2A < ILOAD < 3A 4.75 - 5.25
V
AP1506-5V
η Efficiency VIN = 12V, ILOAD =
3A - 80 - %
11.52 12 12.48
OUT
V Output
Voltage
15V < VIN < 22V
0.2A < ILOAD < 3A 11.4 - 12.6
V
AP1506-12V
η Efficiency VIN = 16V, ILOAD =
3A - 89 - %
AP1506
150KHz, 3A PWM BUCK DC/DC CONVERTER
AP1506 Rev. 2 6 of 13 NOVEMBER 2006
www.diodes.com © 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) (°C)
Efficiency (%)
A
P1506 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
Temperature (TA) (°C)
Efficiency (%)
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) (°C)
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) (°C)
Switch Current Limit (A)
AP1506 Supply Current vs. Temperature
(Vcc = 12V, No Load, Von/off = 0V (Switch ON), Von/off = 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) (°C)
Supply Current (mA)
Sw itch ON
30
35
40
45
50
55
60
-50 -30 -10 10 30 50 70 90 110 130 150
Temperature (TA) (°C)
Supply Current (uA)
Switch OFF
AP1506
150KHz, 3A PWM BUCK DC/DC CONVERTER
AP1506 Rev. 2 7 of 13 NOVEMBER 2006
www.diodes.com © 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) (°
C)
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 vs. Temperature
(Vcc = 12V, Io = 500mA, Vout = 5V)
140
145
150
155
160
165
170
-50 -30 -10 10 30 50 70 90 110 130 150
Temperature (TA) (°C)
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) (°C)
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) (°C)
Vout (V)
AP1506
150KHz, 3A PWM BUCK DC/DC CONVERTER
AP1506 Rev. 2 8 of 13 NOVEMBER 2006
www.diodes.com © Diodes Incorporated
Typical Application Circuit (TO packages)
(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
V
in
GND
Output
AP1506
Co
Capacitor
L1
47uH 5V / 3A
Output Load
R2 R1
C
DELAY
0.1uF
10K
RDELAY
Note: 3. 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 Rev. 2 9 of 13 NOVEMBER 2006
www.diodes.com © Diodes Incorporated
Function 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 regulator.
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
loop.
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 wired to the ground pin.
Thermal Considerations
The AP1506 is available in two packages: a 5-pin TO-220 and a
5-pin surface mount TO-263.
The TO-220 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 (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 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 sided,
multi-layer PC board with large copper areas and/or airflow will
be recommended.
The AP1506 (TO-263 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 Rev. 2 10 of 13 NOVEMBER 2006
www.diodes.com © 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)
"02" = 2002
"01" = 2001
YY WW X X
Xth week: 01~52
~
L: Lead Free Package
(2) TO220-5L
1506-XX
Output Type:
1506: ADJ
1506-33: 3.3V
1506-50: 5.0V
1506-12: 12V
Logo
ID code
Year:
(Top view)
"02" = 2002
"01" = 2001
YY WW X X
Xth week: 01~52
~
L: Lead Free Package
AP1506
150KHz, 3A PWM BUCK DC/DC CONVERTER
AP1506 Rev. 2 11 of 13 NOVEMBER 2006
www.diodes.com © Diodes Incorporated
Package Information
(1) Package Ty pe: TO220-5L
AP1506
150KHz, 3A PWM BUCK DC/DC CONVERTER
AP1506 Rev. 2 12 of 13 NOVEMBER 2006
www.diodes.com © Diodes Incorporated
Package Information (Continued)
(2) Package Ty pe: TO263-5L
AP1506
150KHz, 3A PWM BUCK DC/DC CONVERTER
AP1506 Rev. 2 13 of 13 NOVEMBER 2006
www.diodes.com © Diodes Incorporated
Package Information (Continued)
(3) Package Type: TO220-5L(R) Mechanical drawing
IMPORTANT NOTICE
LIFE SUPPORT
Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes without further
notice to any product herein. Diodes Incorporated does not assume any liability arising out of the application or use of any product described herein; neither
does it convey any license under its patent rights, nor the rights of others. The user of products in such applications shall assume all risks of such use and will
agree to hold Diodes Incorporated and all the companies whose products are represented on our website, harmless against all damages.
Diodes Incorporated products are not authorized for use as critical components in life support devices or systems without the expressed written approval of the
President of Diodes Incorporated.
