AP5002
PWM CONTROL 2A STEP-DOWN CONVERTER
AP5002 Rev. 8 1 of 10 FEBRUARY 2009
www.diodes.com © Diodes In corporat ed
• Input voltage: 3.6V to 20V
• Output voltage: 0.8V to VCC
• Duty ratio: up to 100% PWM control
• Oscillation frequency: 500KHz typical
• Soft-start Current Limit, Enable function
• Thermal Shutdown function
• Built-in internal SW P-channel MOS
• Low ESR output capacitor (MLCC, multi-layer ceramic
capacitor) support
• Efficiency 90%
• SOP-8L: Available in “Green” Molding Compound
(No Br, Sb)
• Lead Free Finish / RoHS Compliant (Note 1)
AP5002 consists of step-down switching regulator with
PWM control. These devices include a reference voltage source,
oscillation circuit, error amplifier, internal PMOS.
AP5002 provides low-ripple power, high efficiency, and excellent
transient characteristics. The PWM control circuit is able to vary
the duty ratio linearly up to 100%. This converter also contains
an error amplifier circuit as well as a soft-start circuit that prevents
overshoot at startup. An enable function, an over current protect
function and a short circuit protect function are built inside, and
when OCP or SCP happens, the operation frequency will be
reduced from 500KHz to 50KHz. Also, an internal compensation
block is built in to minimum external component count.
With the addition of an internal P-channel Power MOS, a coil,
capacitors, and a diode connected externally, these ICs can
function as step-down switching regulators. They serve as ideal
power supply units for portable devices when coupled with the
SOP–8L mini-package, providing such outstanding features as
low current consumption. Since this converter can accommodate
an input voltage up to 22V, it is also suitable for the operation via
an AC adapter.
• PC Motherboard
• LCD Monitor
• Graphic Card
• DVD-Video Player
• Telecom Equipment
• ADSL Modem
• Printer and other Peripheral Equipment
• Microprocessor core supply
• Networking power supply
AP5002 S G - 13
Package Packing
S : SOP-8L 13 : Tape & Reel
Green
G : Green
Device Package
Code Packaging
(Note 2) 13” Tape and Reel
Quantity Part Number Suffix
AP5002SG-13 S SOP-8L 2500/Tape & Reel -13
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.
Features General Description
Applications
Ordering Information
AP5002
PWM CONTROL 2A STEP-DOWN CONVERTER
AP5002 Rev. 8 2 of 10 FEBRUARY 2009
www.diodes.com © Diodes In corporat ed
( Top View )
1
2
3
4
8
7
6
5
FB
Output
Comp
SOP-8L
AP5002
Output
EN
Vss
Vss
VCC
Name Pin Description
FB 1 Feedback pin
EN 2
Power-off pin
H: Normal operation
(Step-down operation)
L: Step-down operation stopped
(
All circuits deactivated
)
Comp 3 Compensation pin
VCC 4 IC power supply pin
Output 5、6 Switch Pin. Connect external
inductor/diode here. Minimize trace
area at this pin to reduce EMI.
VSS 7、8 GND Pin
Block Diagram
Oscillation
Circuit Reference Voltage Source
PWM-Switched
Control Circuit
+
-
Vss
VEN
EN
100uA
Comp
FB
Vcc
Thermal
Shutdown
Output
Pin Assignments Pin Descriptions
AP5002
PWM CONTROL 2A STEP-DOWN CONVERTER
AP5002 Rev. 8 3 of 10 FEBRUARY 2009
www.diodes.com © Diodes In corporat ed
Absolute Maximum Ratings
Symbol Parameter Rating Unit
ESD HBM Human Body Model ESD Protection 5 KV
ESD MM Machine Model ESD Protection 200 V
VCC VCC Pin Voltage VSS - 0.3 to VSS + 22 V
VFB Feedback Pin Voltage VSS - 0.3 to VCC V
VEN EN Pin Voltag e VSS - 0.3 to VIN V
VOUTPUT Switch Pin Volta
g
e VSS - 0.3 to VIN V
PD Power D issipation 1000 mW
TJ Operating Junction Temperature Range -20 to +125 oC
TST Storage Temperature Range -65 to +150 oC
Caution: The absolute maximum ratings are rated values exceeding which the product could suffer physical damage. These values must therefore not be
exceeded under any conditions.
Recommended Operating Conditions
Symbol Parameter Min Max Unit
VIN Input Voltage 3.6 20 V
IOUT Output Current 0 2 A
TA Operating Ambient Temperature -20 85 oC
AP5002
PWM CONTROL 2A STEP-DOWN CONVERTER
AP5002 Rev. 8 4 of 10 FEBRUARY 2009
www.diodes.com © Diodes In corporat ed
Electrical Characteristics (VIN = 12V, TA = 25°C, unless otherwise specified)
Symbol Parameter Conditions Min Typ. Max Unit
VFB Feedback Voltage IOUT = 0.1A 0.784 0.8 0.816 V
IFB Feedback Bias Current IOUT = 0.1A - 0.1 0.5 µA
ICCQ Quiescent Current VFB = 1.2 force drive off - 3 5 mA
ISW Switch Current -- 3.5 - - A
ISD Shutdown Supply Current VEN = 0V - 10 - µA
∆VOUT
/VOUT Line Regulation V IN = 4V~20V, IOUT = 0.2A - 1 2 %
∆VOUT
/VOUT Load Regulation IOUT = 0.1 to 2A - 0.5 1 %
fOSC Oscillation Frequency Measure waveform at SW pin 400 500 600 KHz
VSH EN Pin Input Voltage Evaluate oscillation at SW pin 2.0 - - V
VSL Evaluate oscillation stop at SW pin - - 0.8
ISH EN Pi n Input Leakage
Current Ven = 2V -10 - 10 µA
ISL Ven = 0.8V -10 - 10 µA
TSS Soft-Start Time -- - 3 - ms
RDSON Internal MOSFET Rdson VIN = 5V, VFB = 0V - 110 150 mΩ
VIN = 12V, VFB = 0V - 70 100
Thermal shutdown 140
oC
Minimum Duty Cycle 6.5 %
θJA Thermal Resistance
Junction-to-Ambient SOP-8L (Note 3) 124 oC/W
θJC
T
hermal Resistance
Junction-to-Case SOP-8L (Note 3) 25 oC/W
Notes: 3. Test condition: Device moun ted on 2oz copper, minimum recommended pad layout, FR-4 PCB.
AP5002
PWM CONTROL 2A STEP-DOWN CONVERTER
AP5002 Rev. 8 5 of 10 FEBRUARY 2009
www.diodes.com © Diodes In corporat ed
Typical Application Circuit
U1
AP5002
1
2
3
4 5
6
7
8
FB
EN
COMP
VCC Output
Output
VSS
VSS
C8
0.1uF
C3
0.1uF
C6
0.1uF
C7
0.1uF
C1
330pF
C4
22uF
D1
Dii 723
B340A
L1-(WURTH S05100104)
10uH
1 2
R4
0.8~2K
R1
3.8K
VIN+12V
R2
1.2K
R5
100K VOUT = 3.3V
C2
22uF
ON/OFF
Compensation Capacitor Selection(MLCC)
VIN VOUT R4 C7 C1
12V 5/ 3.3/ 2.5/ 1.8/ 1.5V 0.8~2K 0.1µF 330pF
5V 3.3/ 2.5/ 1.8/ 1.5V 0.8~2K 27nF 330pF
VOUT = 3.3V
10uH
12
R1
3.8K
ON/OFF
U1
AP5002
1
2
3
45
6
7
8
FB
EN
COMP
VCC Output
Output
VSS
VSS
R4
4.7~6.8K
C3
0.1uF
C8
0.1uF
C6
0.1uF
C7
33nF
C1
330pF
C4
470uF
D1
B340A
VIN+12V
R2
1.2K
R5
100K
C2
470uF
Dii 723
L1-(WURTH S05100104)
Notes: 4. VOUT = VFB )
R2
R1
(1 +×
AP5002
PWM CONTROL 2A STEP-DOWN CONVERTER
AP5002 Rev. 8 6 of 10 FEBRUARY 2009
www.diodes.com © Diodes In corporat ed
Typical Performance Characteristics
AP5002 Vi n vs. Fre quency
(Vout=3. 3V; Iout=0. 2A)
510
520
530
540
550
560
570
0 5 10 15 20 25
Vin(V)
Frequency(KHZ)
AP 5002 Temper atur e vs. Fr eq uen cy
(Vout=3.3V; Iout=0. 2A)
485
500
515
530
545
560
575
-20 0 20 40 60 80 100 120
Frequency(KHZ)
Temperature(℃)
AP 5002 Vin vs. FB
(Vout=3. 3V; Iout=0.2A)
0.8
0.802
0.804
0.806
0.808
0 5 10 15 20 25
Vin(V)
VFB(V)
AP5002 Temperature vs. FB
(V ou t=3.3V; I o u t=0. 2A)
0.78
0.79
0.8
0.81
0.82
-203080130
VFB(V)
Temperature(℃)
AP 5002 Effi ciency
0
10
20
30
40
50
60
70
80
90
100
0 0.5 1 1.5 2
Iout(A)
Efficiency(%)
Vout=5V
Vout=3.3V
AP5002
PWM CONTROL 2A STEP-DOWN CONVERTER
AP5002 Rev. 8 7 of 10 FEBRUARY 2009
www.diodes.com © Diodes In corporat ed
Typical Performance Characteristics (Continued)
AP5002 L o ad Reg u latio n
3.3
3.31
3.32
3.33
3.34
3.35
00.511.52
Iout(A)
Vout(V)
AP5002 Line Re gul ation
3.3
3.31
3.32
3.33
3.34
3.35
0 5 10 15 20 25
Vin(V)
Vout(V)
AP 5002 V in vs. I
CCQ
(V o u t= 3 . 3 V )
0
1
2
3
4
5
0 5 10 15 20
Vin(V)
I
CCQ
(mA)
AP 5002 T emp eratu r e vs. I
CCQ
(Vout=3.3V)
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
-20 0 20 40 60 80 100 120
I
CCQ
(mA)
Temperature(℃)
AP5002
PWM CONTROL 2A STEP-DOWN CONVERTER
AP5002 Rev. 8 8 of 10 FEBRUARY 2009
www.diodes.com © Diodes In corporat ed
Typical Performance Characteristics (Continued)
AP5002
V
out Ripple
(Vin=12V; Vout=5V; Iout=0.2A)
A
P5002
V
out Ripple
(Vin=12V; Vout=5V; Iout=2A)
Test Circuit
A
FBVCC
VSS
EN
open
open
FBVCC
VSS
EN
+
-
Oscillation
OUTPUT OUTPUT
A
FB
VCC
VSS
EN
+
-+
-
V
OUTPUT
COMP COMP
COMP
Enable function test Feedback function test
Oper ation function te st
1.2K
6.8K
22u
6.8K 1500p
AP5002
PWM CONTROL 2A STEP-DOWN CONVERTER
AP5002 Rev. 8 9 of 10 FEBRUARY 2009
www.diodes.com © Diodes In corporat ed
Functional Description
PWM Control
The AP5002 consists of DC/DC converters that employ a
pulse-width modulation (PWM) system.
In converters of the AP5002, the pulse width varies in a range up
to 100%, according to the load current. The ripple voltage
produc ed by the s witchin g can eas ily be remo ved thr ough a fil ter
because the switching frequency remains constant. Therefore,
these converters provide a low-ripple powe r ov er broad ran ges o f
input voltage and load current.
RDS(ON) Current Limiting
The current limit threshold is set by the internal circuit.
Setting the Output Voltage
Application circuit item shows the basic application circuit with
adjustable output version. The external resistor sets the output
voltage according to the following equation:
VOUT (V) R1 (KΩ) R2 (KΩ)
5 6.4 1.2
3.3 3.8 1.2
2.5 2.6 1.2
1.8 3.3 2.6
1.5 3.3 3.7
1.2 3.3 6.5
1 3.3 13
Inductor Selection
For most designs, the operates with inductors of 10µH to
22µH. The inductor value can be derived from the following
equation:
()
oscL
ONOUTIN fI2 TVV
L×Δ×
−
=
Where is inductor Ripple Current. Large value inductors lower
ripple current and small value inductors result in high ripple
currents. Choose induct or ripple current approximately 15% of the
maximum load current 2A , ∆IL=0.3A. The DC curr ent rating o f the
inductor should be at least equal to the maximum load current
plus half the ripple current to prevent core saturation (2A +0.15A ).
Input Ca pacitor Selec tion
EL CAP
This capacitor should be located close to the IC using short leads
and the voltage rating should be approximately 1.5 times the
maximum input voltage. The RMS current rating requirement for
the input capacitor of a buck regulator is approximately 1⁄2 the
DC load current. A low ESR input capacitor sized for maximum
RMS current must be used. A 470µF low ESR capacitor for most
applications is sufficient.
MLCC CAP
A 22µF MLCC capacitor for most applications is sufficient.
Output Ca pacitor Selec tion
EL CAP
The output capacitor is required to filter the output voltage and
provides regulator loop stability. The important capacitor
parameters are t he 100K H z Equ i va lent Series R esistance (ESR),
the RMS ripples current rating, voltage rating and capacitance
value. For the output capacitor, the ESR value is the most
important parameter. The output ripple can be calculated from
the following formula.
ES
R
IV LRIPPLE ×
Δ
=
The bulk capacitor’s ESR will determine the output ripple voltage
and the initial voltage drop after a high slew-rate transient.
An aluminum electrolytic capacitor's ESR value is related to the
capacitance and its voltage rating. In most case, higher voltage
electrolytic capacitors have lower ESR values. Most of the time,
capacitors with much higher voltage ratings may be needed to
provide the low ESR values requ ired fo r low ou tput ripple v oltage .
MLCC CAP
A 22µF MLCC capacitor for most applications is sufficient.
PCB Layout Guide
If you need low TC & TJ or large PD(Power Dissipation), The dual
SW pins(5& 6) and VSS pins(7& 8)on the SOP-8L package are
inter nally connec ted to die pad, The PCB layout should all ow for
maximum possible copper area at the SW pins.
1. Connect C3 to VCC and VSS pin as closely as possible to get
good power filter effect.
2. Connect R4 to VCC and OCSET pin as closely as possible.
3. Connect ground side of the C2 & D1 as closely as possible.
Typical PC Board Layout
Top Side Layout Guide
Bottom Side Layout Guide
Use vias to conduct the heat into the backside of
PCB layer. The PCB heat sink copper area should be
solder- painted without maske d. This approaches a
“best case” pad heat sink.
AP5002
PWM CONTROL 2A STEP-DOWN CONVERTER
AP5002 Rev. 8 10 of 10 FEBRUARY 2009
www.diodes.com © Diodes In corporat ed
Marking Information
( Top View )
AP5002
YY WW
XX
Logo
Part Number
5
8
41
WW : Week : 01~52; 52
YY : Year : 08, 09,10~
G : Green
X : Internal Code
represents 52 and 53 week
Package Information (All Dimensions in mm)
1.27typ 0.3/0.5
7°~9°
4.85/4.95
3.85/3.95
5.90/6.10
0.15/0.25
7°~9°
0.62/0.82
0.10/0.20
Gauge Plane
0.254
Seating Plane
0.35max. 45°
Detail "A"
Detail "A"
1.30/1.50
1.75max.
Land Pattern Recommendation
(Unit: mm)
6x-1.27
8x-1.55
8x-0.60
5.4
0°/8°
IMPORTANT NOTICE
LIFE SU PPOR T
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.
