AP1512/A
50KHz, 2A/3A PWM BUCK DC/DC CONVERTER
AP1512/A Rev. 4 1 of 12 MAY 2008
www.diodes.com © Diodes Incorporated
Lead-free
Features General Description
The AP1512/A is a monolithic IC designed for use as a
step-down DC/DC converter w ith the ability of driving a 2A (3A for
AP1512A) load without additional transistor components. The
board space is reduced since AP1512/A requires few external
components. The external shutdown function is controlled by
logic level and can be put into standby mode. The internal
compensation ensures feedback control has good line and load
regulation without external design. Both an integrated Thermal
shutdown and Current Limit function are provided to prevent
damage from exceeding temperature operation and against
exceeding the current operating of the output switch. The
AP1512/A operates at a switching frequency of 50KHz 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%
tolerance on the oscillator frequency. The AP151 2/A offers fixed
output voltages of 3.3V, 5V, 12V, plus Adjustable. The package is
available in a standard 5-lead TO263 package.
• Output voltage: 3.3V, 5V, 12V and adjustable output
version
• Adjustable version output voltage range, 1.23V to
37V+4%
• 50KHz +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 60V
• Output load current: 2A (for AP1512)
3A (for AP1512A)
• Low power standby mode
• Built-in switching transistor on chip
• Lead Free Finish/ RoHS Compliant (Note 1)
Applications
• Simple High-efficiency step-down regulator
• On-card switching regulators
• Positive to negative converter
Ordering Information
Package
K5 : TO263-5L
Output Version
AP1512 X - XX XX X X
Packing
-U : Tube
-13 : Tape & Reel
Blank : Adjustable
33 : 3.3V
50 : 5.0V
12 : 12V
Part Number
Blank : 2A
A : 3A
Lead Free
L : Lead Free
Tube 13” Tape and Reel
Device Package
Code Packaging
(Note 2) Quantity Part Number
Suffix Quantity Part Number
Suffix
AP1512X-XXK5 K5 TO263-5L 50 -U 800/Tape & Reel -13
Notes: 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied, see EU Directive 2002/95/EC Annex Notes.
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.
AP1512/A
50KHz, 2A/3A PWM BUCK DC/DC CONVERTER
AP1512/A Rev. 4 2 of 12 MAY 2008
www.diodes.com © Diodes Incorporated
( Top View )
TO263-5L
1 VIN
5 SD
4 FB
3 GND
2 Output
Metal Tab GND
Current
Source
bias 1.235V
Reference 2.5V
Regulator
50KHz
OSC.
Start
up
+
+
_
+
_
Thermal
Limit
Pre-driver
Comp
Comp
Gnd
Output
VIN
SD
FB
220mV
200mV
2A
Switch
+
_
_
Amp Comp
Frequecy
compen-
sation (3A for
AP1512A)
Pin Assignments Pin Descriptions
Name Description
VIN Operating voltage input
Output Switching output
GND Ground
FB Output voltage feedback control
SD ON/OFF Shutdown
Block Diagram
AP1512/A
50KHz, 2A/3A PWM BUCK DC/DC CONVERTER
AP1512/A Rev. 4 3 of 12 MAY 2008
www.diodes.com © Diodes Incorporated
Absolute Maximum Ratings
Symbol Parameter Rating Unit
ESD HBM Human Body Model ESD Protection 4.5 KV
ESD MM Machine Model ESD Protection 450 V
VCC Supply Voltage +63 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
TST Storage Temperature -65 to +150 oC
TJ Operating Junction Temperature -40 to +125 oC
VOP Operating Volt age +4.5 to +60 V
Recommended Operating Conditions
Symbol Parameter Min Max Unit
VIN Input Voltage 4.5 60 V
IOUT Output Current 0 2 A
TA Operating Ambient Temperature -20 85 o
C
AP1512/A
50KHz, 2A/3A PWM BUCK DC/DC CONVERTER
AP1512/A Rev. 4 4 of 12 MAY 2008
www.diodes.com © Diodes Incorporated
Electrical Characteristics (All Output Voltage Versions)
Unless otherwise specified, VIN = 30V for all version. ILOAD = 0.5A
Specifications with boldface type are for full operating temperature range, the other type are for TA = 25ºC.
Symbol Parameter Conditions Min Typ. Max Unit
8
IB Feedback Bias Current VFB = 1.3V
(Adjustable version only) 5
10 μA
42.5 50 57.5
FOSC Oscillator Frequency 40 60 KHz
1.4
VSAT Saturation Voltage IOUT = 2A
no outside circuit
VFB = 0V force driver on 1.3
1.5 V
Max. Duty Cycle(ON) VFB = 0V force driver on 100
DC Min. Duty cycle(OFF) VFB = 12V force driver off 0 %
4.5
ICL Current Limit for AP1512 peak current
no outside circuit
VFB = 0V force driver on 2.5 3 5.5 A
5
ICL Current Limit for AP1512A peak current
no outside circuit
VFB = 0V force driver on 3.2 4 6 A
Output = 0 no outside circuit
VFB = 12V force driver off -250 uA
IL Output = -1
Output
leakage
current VIN = 60V -2 -60 mA
IQ Quiescent Current VFB = 12V force driver off 5 10 mA
450
500
ISTBY Standby Quiescent
Current ON/OFF pin = 5V
VIN = 60V 350 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 -5
IL ON/OFF pin input current VLOGIC = 0.5V (ON) -0.8 -10 uA
2.5
θJC Thermal Resistance TO263-5 L Junction to case 3.5
oC/W
28
θJA Thermal Resi st ance
With copper area of
approximately 3 in2 TO263-5L Junction to ambient 23
oC/W
AP1512/A
50KHz, 2A/3A PWM BUCK DC/DC CONVERTER
AP1512/A Rev. 4 5 of 12 MAY 2008
www.diodes.com © Diodes Incorporated
Electrical Characteristics (Continued)
AP1512
Symbol Parameter Conditions VMIN Typ. VMAX Unit
AP1512-ADJ FB
V Output
Feedback
10V < VIN < 60V
0.2A < ILOAD < 2A
VOUT programmed for 3V
1.193
1.18
1.23 1.267
1.28 V
AP1512-3.3V OUT
V Output voltage 10V < VIN < 60V
0.2A < ILOAD < 2A
3.168
3.135
3.3 3.432
3.465 V
AP1512-5V OUT
V Output voltage 10V < VIN < 60V
0.2A < ILOAD < 2A
4.8
4.75
5 5.2
5.25 V
OUT
V Output voltage 15V < VIN < 60V
0.2A < ILOAD < 2A
11.52
11.4
12 12.48
12.6 V
AP1512-12V
η Efficiency VIN = 30V, ILOAD = 2A 83 %
Specifications with boldface type are for full operating temperature range, the other type are for TA = 25ºC.
AP1512A
Symbol Parameter Conditions VMIN Typ. VMAX Unit
AP1512A-ADJ FB
V Output
Feedback
10V < VIN < 60V
0.2A < ILOAD
VOUT programmed for 3V
1.193
1.18
1.23 1.267
1.28 V
AP1512A-3.3V OUT
V Output voltage 10V < VIN < 60V
0.2A < ILOAD
3.168
3.135
3.3 3.432
3.465 V
AP1512A-5V OUT
V Output voltage 10V < VIN < 60V
0.2A < ILOAD
4.8
4.75
5 5.2
5.25 V
OUT
V Output voltage 15V < VIN < 60V
0.2A < ILOAD
11.52
11.4
12 12.48
12.6 V
AP1512A-12V
η Efficiency VIN = 30V, ILOAD = 3A 80 %
Specifications with boldface type are for full operating temperature range, the other type are for TA = 25ºC.
AP1512/A
50KHz, 2A/3A PWM BUCK DC/DC CONVERTER
AP1512/A Rev. 4 6 of 12 MAY 2008
www.diodes.com © Diodes Incorporated
Typical Performance Characteristics
AP1512A Current Limit vs. Temperature
( Vcc = 60V, Vout = 5V )
3
3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
4
-50 0 50 100 150
Temper atur e ( TA) ( °C)
Current Limit (A)
AP1512A Efficiency vs. Supply Voltage
( Vout = 5V, Iout = 3A )
0
10
20
30
40
50
60
70
80
90
100
0 122436486
S upply Volt age( V)
Efficiency(%)
0
AP1512 Efficiency vs. Temperature
( Vin = 12V, Vout = 5V, Io = 2A )
0
10
20
30
40
50
60
70
80
90
100
-50 -30 -10 10 30 50 70 90 110 130 150
T emperature ( TA) ( °C)
Ef f iciency (%)
AP1512 Efficiency vs. Temperature
( Vin = 12V, Vout = 3.3V, Io = 2A )
0
10
20
30
40
50
60
70
80
90
100
-50 -30 -10 10 30 50 70 90 110 130 150
Tem
p
erature
(
TA
)
(
°C
)
Eff iciency (%)
AP1512 Supply Current vs. Temperature
( Vcc = 12V, No Load, Von/off = 0V (Switch ON), Von/off = 5V (Switch OFF))
0
1
2
3
4
5
6
7
8
-40 -25 -10 5 20 35 50 65 80 95 110 125
Supply Current (mA)
T emperat ur e ( T A) (°C)
Sw itch ON
0
10
20
30
40
50
60
70
80
90
100
-40 -25 -10 5 20 35 50 65 80 95 110 125
Supply Cur r ent (uA )
Temperatur e ( TA) (°C)
Sw itch OFF
AP1512/A
50KHz, 2A/3A PWM BUCK DC/DC CONVERTER
AP1512/A Rev. 4 7 of 12 MAY 2008
www.diodes.com © Diodes Incorporated
Typical Performance Characteristics (Continued)
AP1512 Frequency v s. Temperature
( Vcc = 12V, Io = 1A, Vout = 5V )
40
45
50
55
60
-50-30-101030507090110130150
Temperat ur e ( TA) (° C)
F r equency ( K Hz )
AP1512 Current Limit vs. Temperature
( Vcc = 60V, Vout = 5V )
2.8
3
3.2
3.4
3.6
-50 0 50 100 150
Current Limit (A)
T e mperature ( TA) (° C)
AP1512 Quiescent Current vs. Supply Voltage
( force driver off )
5.2
5.4
5.6
5.8
6
6.2
0 122436486
Quiescent Current (A)
0
S upply Voltage( V)
AP1512/A
50KHz, 2A/3A PWM BUCK DC/DC CONVERTER
AP1512/A Rev. 4 8 of 12 MAY 2008
www.diodes.com © Diodes Incorporated
Typical Application Circuit
(1) Adjustable Type Circuit
A. Vin = 10V~60V, Vout = 5V; Iout = 0.3A~2A, Iout below 0.3A DCM
C5
1n
L1
47uH
12
R2
3K
Vin
C2
1u
D1
B360/B
ON/OFF
R3
1K
C1
100uF/100V
Vout
AP1512/A
1
5
2
4
3
Vin
SD
OUTPUT
FB
GND
0.1u
C3
470uF/16V
C7
B. Vin = 10V~60V, Vout = 3.3V, Iout = 0.3A~2A, Iout below 0.3A DCM
C5
1n
L1
47uH
12
R2
2K
Vin
C2
1u
D1
B360/B
ON/OFF
R3
1.2K
C1
100uF/100V
Vout
AP1512/A
1
5
2
4
3
Vin
SD
OUTPUT
FB
GND
0.1u
C3
470uF/16V
C7
AP1512/A
50KHz, 2A/3A PWM BUCK DC/DC CONVERTER
AP1512/A Rev. 4 9 of 12 MAY 2008
www.diodes.com © Diodes Incorporated
Typical Application Circuit ( Continued )
(2) Fixed Type Circuit
A. Vin = 10V~60V, Vout = 5V, Iout = 0.7A~2A, Iout below 0.7A DCM
L1
47uH
12
Vin
C2
1u
D1
B360/B
ON/OFF
C1
100uF/100V
Vout
AP1512/A
1
5
2
4
3
Vin
SD
OUTPUT
FB
GND
10n C3
470uF/16V
C7
B. Vin = 10V~60V, Vout = 3.3V, Iout = 0.7A~2A, Iout below 0.7A DCM
L1
33uH
12
Vin
C2
3.3u
D1
B360/B
ON/OFF
C1
220uF/100V
Vout
AP1512/A
1
5
2
4
3
Vin
SD
OUTPUT
FB
GND
3.3u C3
1500uF/16V
C7
AP1512/A
50KHz, 2A/3A PWM BUCK DC/DC CONVERTER
AP1512/A Rev. 4 10 of 12 MAY 2008
www.diodes.com © Diodes Incorporated
Functional Description
+VIN
This is the positive input supply for the IC switching regulator. A suitable input b ypass 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, 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 a minimum.
Feedback
Senses the regulated output voltage to complete 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 SD 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 Considerations
The AP1512/A is available in a 5-pin surface mount TO-263 package.
The TO-263 surface mount package tab is designe d to be soldered to the copper on a printed circuit b oard. 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 0.4 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 AP1512/A (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 2A are used, double sided or multilayer 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, multilayer b oard 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.
AP1512/A
50KHz, 2A/3A PWM BUCK DC/DC CONVERTER
AP1512/A Rev. 4 11 of 12 MAY 2008
www.diodes.com © Diodes Incorporated
Marking Information
(1) TO263-5L
1512X-XX
Output Type :
1512: ADJ
1512-33: 3.3V
1512-50: 5.0V
1512-12: 12V
Logo
Internal code
Year:
(Top view)
"08" = 2008
"07" = 2007
YY WW X X Xth week: 01~52
~
L : Lead Free
Package Information (All Dimensions in mm)
(1) Package Type: TO263-5L
AP1512/A
50KHz, 2A/3A PWM BUCK DC/DC CONVERTER
AP1512/A Rev. 4 12 of 12 MAY 2008
www.diodes.com © Diodes Incorporated
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.
