AP5002
PWM CONTROL 2A STEP-DOWN CONVERTER
AP5002 Rev. 6 1 of 10 JUNE 2008
www.diodes.com © Diodes Incorporated
Features General Description
AP5002 consists of step-down switching regulator with PWM
control. These devices include a reference voltage source,
oscillation circuit, error amplifier, internal PMOS.
• Input voltage: 3.6V to 20V
• Output voltage: 0.8V to VCC
• Duty ratio: up to 100% PWM control
• Oscillation frequency: 500KHz typical 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.
• 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)
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 t he operation via
an AC adapter.
Applications
• PC Motherboard
• LCD Monitor
• Graphic Card
• DVD-Video Player
• Telecom Equipment
• ADSL Modem
• Printer and other Peripheral Equipment
• Microprocessor core supply
• Networking power supply
Ordering Information
AP5002 S G - X
Package Packing
S : SOP-8L U : Tube
13 : Taping & Reel
Lead Free
G : Green
Tube 13” Tape and Reel
Device Package
Code Packaging
(Note 2) Quantity Part Number
Suffix Quantity Part Number
Suffix
AP5002SG-U S SOP-8L 100 -U NA NA
AP5002SG-13 S SOP-8L NA NA 2500/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.
AP5002
PWM CONTROL 2A STEP-DOWN CONVERTER
AP5002 Rev. 6 2 of 10 JUNE 2008
www.diodes.com © Diodes Incorporated
( 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-of f 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 tra ce
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. 6 3 of 10 JUNE 2008
www.diodes.com © Diodes Incorporated
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 Voltage VSS - 0.3 to VIN V
VOUTPUT Switch Pin Voltage VSS - 0.3 to VIN V
PD Power Dissi pation 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 theref ore 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. 6 4 of 10 JUNE 2008
www.diodes.com © Diodes Incorporated
Electrical Characteristics (VIN = 12V, TA = 25°C, unless other wise 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 VIN = 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 Evaluate oscillation at SW pin 2.0 - -
VSL EN Pin Input Voltage Evaluate oscillation stop at SW pin - - 0.8 V
ISH Ven = 2V -10 - 10 µA
ISL EN Pin Input Leakage
Current Ven = 0.8V -10 - 10 µA
TSS Soft-Start Time -- - 3 - ms
VIN = 5V, VFB = 0V - 110 150
RDSON Internal MOSFET Rdson VIN = 12V, VFB = 0V - 70 100 mΩ
Thermal shutdown 140
oC
Minimum Duty Cycle 6.5 %
θJA Thermal Resist ance
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 mounted on 2oz copper, minimum recommended pad layout, FR-4 PCB.
AP5002
PWM CONTROL 2A STEP-DOWN CONVERTER
AP5002 Rev. 6 5 of 10 JUNE 2008
www.diodes.com © Diodes Incorporated
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 Capacito r Selectio n(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. 6 6 of 10 JUNE 2008
www.diodes.com © Diodes Incorporated
Typical Performance Characteristics
AP 5002 Vi n vs. Freque ncy
(V out=3.3V; Iout= 0.2A)
510
520
530
540
550
560
570
0 5 10 15 20 25
Vin(V)
Frequency(KHZ)
AP5002 Temperature vs. Frequency
(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 Vi n vs. F B
(V out=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 T emperature vs. F B
(V o ut=3. 3V; I o ut=0. 2A)
0.78
0.79
0.8
0.81
0.82
-2030801
VFB(V)
30
Temperature(℃)
AP5002 Effi ci ency
0
10
20
30
40
50
60
70
80
90
100
00.511.5
Iout(A)
Efficiency(%)
2
Vout=5V
Vout=3.3V
AP5002
PWM CONTROL 2A STEP-DOWN CONVERTER
AP5002 Rev. 6 7 of 10 JUNE 2008
www.diodes.com © Diodes Incorporated
Typical Performance Characteristics (Continued)
AP 5002 Load Regu l ation
3.3
3.31
3.32
3.33
3.34
3.35
0 0.5 1 1.5 2
Iout(A)
Vout(V)
AP 5002 Li ne Regulation
3.3
3.31
3.32
3.33
3.34
3.35
0 5 10 15 20 25
Vin(V)
Vout(V)
AP 5002 Vi n vs. I
CCQ
(V out=3.3V)
0
1
2
3
4
5
0 5 10 15 20
Vin(V)
I
CCQ
(mA)
AP5002 Temper ature vs. ICCQ
(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. 6 8 of 10 JUNE 2008
www.diodes.com © Diodes Incorporated
Typical Performance Characteristics (Continued)
AP5002 Vout Ripple
(Vin=12V; Vout=5V; Iout=0.2A)
AP5002 Vout 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
Operation function test
1.2K
6.8K
22u
6.8K 1500p
AP5002
PWM CONTROL 2A STEP-DOWN CONVERTER
AP5002 Rev. 6 9 of 10 JUNE 2008
www.diodes.com © Diodes Incorporated
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
produced by the switching can easily be removed through a filter
because the switching frequency remains constant. Therefore,
these converters provide a low-ripple power over broad ranges of
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 fI TVV
L×Δ×
−
=2
Where is inductor Ripple Current. Large value inductors lower
ripple current and small value inductors result in high ripple
currents. Choose inductor ripple current approximately 15% of the
maximum load current 2A, ∆IL=0.3A. The DC current rating of 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 Capacitor Selection
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 Capacitor Selection
EL CAP
The output capacitor is required to filter the output voltage and
provides regulator loop stability. The important capacitor
parameters are the 100KHz Equivalent Series Resistance (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 required for low output ripple voltage.
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
internally connected to die pad, The PCB layout should allow for
maximum possible copper area at the SW pins.
1. Connect C3 to VCC and VSS p in 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 masked. This approaches a
AP5002
PWM CONTROL 2A STEP-DOWN CONVERTER
AP5002 Rev. 6 10 of 10 JUNE 2008
www.diodes.com © Diodes Incorporated
Marking Information
AP5002
(Top view)
YY XX
Part Number
Logo
Xth week: 01~52
Year: "07" = 2007
"08" = 2008
XG : Green
XInternal Code
8765
1234
~
SOP-8L
Package Information (All Dimensions in mm)
1.27typ 0.3/0.5
7°~9°
4.80/5.30
3.70/4.10
5.79/6.20
0.20typ
7°~9°
3.70/4.10
0.38/1.27
0.08/0.25
Gauge Plane
0.254
Seating Plane
0.35max. 45°
Detail "A"
Detail "A"
1.30/1.50
1.75max.
Land Pattern Recommendation
0.78
(Unit: mm)
6x-1.27
8x-1.55
8x-0.60
5.4
IMPORT ANT NOTICE
LI FE 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.
