AP5004
PWM CONTROL 2.5A STEP-DOWN CONVERTER
Description
The AP5004 is a step-down switching regulator with PWM
control and includes a reference voltage source, oscillation
circuit, error amplifier, and an internal NMOS.
AP5004 provides low-ripple power, high efficiency, and
excellent transient characteristics. The PWM control circuit is
able to vary the duty ratio linearly from 0% up to 90%. 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
300 KHz to 50 KHz. Also, an internal compensation block has
been designed in to minimize the external component count.
With built-in power NMOS, a step-down switching regulator
can easily be built by adding a coil, capacitors, and a diode.
The combination of high efficiency, low standby current, high
input voltage (32V), and high output current (2.5A)in a small
SOP-8L package gives the AP5004 an unprecedented
advantage in any high power system applications.
Pin Assignments
(Top View )
1
EN
2
FB
Vboost
AP5004
3
Output
SOP-8L
Applications
• Microprocessor Core Supply
• Networking Power Supply
• LCD MNT, TV Power Supp l y
• Telecom Power Supply
8
GND
7
GND
6
Vcc
54
Vcc
Features
• Input Voltage: 10V to 32V
• Adjustable Output Voltage from 0.8V to 6V
• Duty Ratio: 0% to 90% PWM control
• Oscillation Frequency: 300KHz typical
• Short Circuit Protect Frequency:50 KHz
• 2uA Maximum Standby Current
• Current Limit, Enable Function
• Thermal Shutdown Function
• Built-in Internal SW N-channel MOS
• SOP-8L: Available in “Green” Molding Compound
(No Br, Sb)
• Lead Free Finish/ RoHS Compliant (Note 1)
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.
AP5004
Document number: DS31444 Rev. 5 - 2
1 of 11
www.diodes.com
August 2010
© Diodes Incorporated
Typical Application Circuit
AP5004
PWM CONTROL 2.5A STEP-DOWN CONVERTER
C7 0.1uF
U1
VIN
C2
220uF/63V
Notes: 2. Suggested DIODES Power Schottky P/N: PDS540 or B540C.
C3
0.1uF
R5
100K
C6
0.1uF
3
5
6
1
Vboost
VCC
VCC
EN
Note : V
R
AP5004
OUT
4
Output
2
FB
7
GND
8
GND
x (1+R1/R2)
= V
FB
= 100 ~ 300 ohm
B
L1-(WURTH 744132)
33uH
2
1
R1
685ohm
D1
B340
R2
130ohm
C1
100pF
C4
470uF/16V
VOUT = 5V
C5
0.1uF
Pin Descriptions
Pin Name Pin # Description
EN 1
FB 2 Feedback pin
V
3 High-side gate driver boost pin
boost
Output 4 Switch output pin
VCC
GND
5、6
7、8
H: Normal operation
L: Step-down operation stopped
VCC
GND pin
AP5004
Document number: DS31444 Rev. 5 - 2
2 of 11
www.diodes.com
August 2010
© Diodes Incorporated
Functional Block Diagram
AP5004
PWM CONTROL 2.5A STEP-DOWN CONVERTER
Output
Vcc
Driver
Oscillation
Circuit
PWM -Switched
Control Circuit
Reference Voltage
+
-
FB
VL
Thermal
Shutdown
Vboost
V
EN
GNDEN
Absolute Maximum Ratings
Symbol Parameter Rating Unit
ESD HBM Human Body Model ESD Protection 1.8 KV
ESD MM Machine Model ESD Protection 550 V
VCC VCC Pin Voltage VSS - 0.3 to VSS + 35 V
VFB V
VEN EN Pin Voltage VSS - 0.3 to V
V
V
boost
V
Switch Pin Voltage VSS - 0.3 to V
OUTPUT
TJ Operating Junction Temperature Range -10 to +125
T
Storage Temperature Range -40 to +150
ST
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.
Pin Voltage VSS - 0.3 to VCC V
OUT
+ 0.3 V
CC
Pin Voltage V
boost
+ 7V V
OUTPUT
+ 0.3 V
CC
o
C
o
C
Recommended Operating Conditions
Symbol Parameter Min Max Unit
VIN Input Voltage 10 32 V
I
Output Current 0 2.5 A
OUT
TA Operating Ambient Temperature -10 85
AP5004
Document number: DS31444 Rev. 5 - 2
3 of 11
www.diodes.com
August 2010
© Diodes Incorporated
o
C
AP5004
)
PWM CONTROL 2.5A STEP-DOWN CONVERTER
Electrical Characteristics (V
Symbol Parameter Conditions Min Typ. Max Unit
VFB Feedback Voltage 0.780 0.8 0.820 V
VIN Input Voltage 10 - 32 V
I
Standby Current VEN =0V - 2 - µA
STBY
∆V
OUT/VOUT
∆V
OUT/VOUT
f
OSC
f
OSC1
DC
VIH
VIL
ISH
R
DS(ON)
I
LIMIT
θ
θ
Notes: 3. Test condition for SOP-8L: Device mounted on 2oz copper, minimum recommended pad layout, FR-4 PCB.
Line Regulation V
Load Regulation I
Oscillation Frequency Measure waveform at SW pin 240 300 360 KHz
Frequency of Current Limit or
Short Circuit Protect
Maximum Duty Cycle V
Minimum Duty Cycle VFB =1.0V - 0 - %
EN Pin Logic Input Threshold
Voltage
ISL
η
JA
JC
EN Pin Input Leakage Current
Internal MOSFET R
Current Limit 3.5 - - A
Efficiency V
Thermal Resistance Junctionto-Ambient
Thermal Resistance Junctionto-Case
= 12V, TA=25°C, unless otherwise specified)
IN
= 10V~32V -
IN
= 0.1 to 2.5A - 1 1.5 %
OUT
±1.0 ±1.5
Measure waveform at SW pin - 50 - KHz
=0.5V - 90 - %
FB
Regulator ON 2.0 - Regulator OFF - - 0.8
- 20 - µA
- -10 - µA
- 80 120 mΩ
DS(ON
= 12V, V
IN
OUT
= 5V, I
= 2.5A - 90 - %
OUT
SOP-8L (Note 3) - 124 SOP-8L (Note 3) - 25 -
%/V
o
C/W
o
C/W
V
AP5004
Document number: DS31444 Rev. 5 - 2
4 of 11
www.diodes.com
August 2010
© Diodes Incorporated
Typical Performance Characteristics
Load Regulation Line Regulation
1.2
AP5004
PWM CONTROL 2.5A STEP-DOWN CONVERTER
1.5
1
0.8
0.6
0.4
Load Regulation(%)
0.2
0
0123
Iout(A)
Frequency vs. Vin Iccq vs. Vin
330
325
320
Frequency(KHz)
315
310
0 5 10 15 20 25 30 35
Vout=5V;Iout=0.2A
Vin(V)
Istandby vs. Vin
0.15
VEN=0V
1.2
0.9
0.6
Line Regulation(%)
0.3
0
0 4 8 121620242832
7.45
7.4
7.35
7.3
7.25
7.2
7.15
Quiescent Curren t(m A)
7.1
7.05
VFB=1V
0 5 10 15 20 25 30 35
Vin(V)
Vin(V)
0.12
0.09
0.06
Standby Current(uA)
0.03
0
0 5 10 15 20 25 30 35
AP5004
Document number: DS31444 Rev. 5 - 2
Vin(V)
5 of 11
www.diodes.com
August 2010
© Diodes Incorporated
AP5004
PWM CONTROL 2.5A STEP-DOWN CONVERTER
Typical Performance Characteristics (Continued)
Vout Ripple
(Vcc= 12V, Vout= 5V, Iout= 0A, Vripple= 19.0mV)
(Vcc= 12V, Vout= 5V, Iout= 2.5A, Vripple= 35.0mV)
Load Transient Response
(Iout= 0.1~2.5A, Vin= 12V, Vout= 5V)
Load Transient Response
(Iout= 0.1~2.5A, Vin= 32V, Vout= 5V)
Vout Ripple
AP5004
Document number: DS31444 Rev. 5 - 2
6 of 11
www.diodes.com
August 2010
© Diodes Incorporated
Test Circuit
AP5004
PWM CONTROL 2.5A STEP-DOWN CONVERTER
open
OUTPUT OUTPUT
A
EN
Vboost
GND
open
FBVcc
Oscillation
open
A
+
-
Vcc
EN
Vboost
FB
GND
Enable function test Feedback function test
33uH
0.1uF
Vboost
Vcc
+
-
220uF
EN
Operation function test
OUTPUT
GND
FB
470uF
+
-
530 ohm
V
100 ohm
AP5004
Document number: DS31444 Rev. 5 - 2
7 of 11
www.diodes.com
August 2010
© Diodes Incorporated
AP5004
(
PWM CONTROL 2.5A STEP-DOWN CONVERTER
Functional Description
PWM Control
The AP5004 consists of DC/DC converters that employ a pulse-width modulation (PWM) system. The PWM
controller is internally clocked by a fixed 300KHz oscillator.
When used as a converter, the AP5004’s pulse width varies in a range from 0% to 90%, 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.
Enable Control
The Enable Control allows the output of the AP5004 to be turned ON or OFF. Connecting the Enable pin to GND
or any voltage source lower than 0.8V will turn the output OFF. In the OFF state, the current drawn through the
V
input is approximately 2µA. Please note that the slew rate from ON to OFF must be >0.013v/µs to ensure
CC
proper operation.
BOOST Capacitor
This capacitor boosts the gate drive to the internal MOSFET above V
conduction losses in the power switch to maintain high efficiency. The recommended value of the capacitor is
0.1µF. The capacitor must be connected from pin 3 to the switch output, pin 4.
Feedback
This is the input to a two-stage high gain amplifier, which drives the PWM controller. Two external resistors are
required to set the DC output voltage. For stable operation of the power supply, it is important to prevent coupling
of any inductor flux to the feedback input.
Current Limit
The current limit threshold is set by the internal circuit such that the minimum switching current is 3.5A. If the
switching current exceeds the threshold, the output voltage will drop and the switching frequency will be reduced
to 50KHz.
Inductor Selection
Most designs operate with inductors of 15µH to 33µH. The inductor value can be derived from the following
equation:
)
OUT
f
osc
××Δ
V
OUT
V
IN
V
V
−
IN
L
=
I
L
Large value inductors will result in a lower ripple current where as small value inductors will result in high ripple
currents. The inductor ripple current should be set to approximately 15% of the maximum load current 2.5A,
∆IL=0.375A. 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+0.19A).
Input Capacitor Selection
The input current to the step-down converter is discontinuous, and therefore an input capacitor C2 is required to
supply the AC current to the step-down converter while maintaining the DC input voltage. A low ESR capacitor is
required to keep the noise at the IC to a minimum. Its RMS current rating should be greater than approximately
half of the DC load current.
AP5004
Document number: DS31444 Rev. 5 - 2
8 of 11
www.diodes.com
to fully turn it ON thus minimizing
IN
August 2010
© Diodes Incorporated
AP5004
×Δ≅
PWM CONTROL 2.5A STEP-DOWN CONVERTER
Functional Description (Continued)
Output Capacitor Selection
An output capacitor is required to maintain the DC output voltage. Low ESR capacitors are preferred to keep the
output voltage ripple low. The characteristics of the output capacitor also affect the stability of the regulation
control system. The ESR dominates the impedance at the switching frequency.The output ripple is calculated as:
V
RIPPLE
Output Rectifier Diode
The output rectifier diode supplies the current to the inductor when the high-side switch is OFF. To reduce losses
due to the diode forward voltage and recovery times, use a Schottky rectifier.
PCB Layout Guide
The dual Output pin (4) and VSS pins (7 & 8) on the SOP-8L package are internally connected to die pad. If low
T
& TJ or a large PD (Power Dissipation) is needed, the PCB layout should allow for maximum possible copper
C
area exposure at the SW pins. Please also follow the steps below to reduce switching noise.
1. Connect C3 to VCC and VSS pin as closely as possible to get good power filter effect.
2. Connect ground side of the C2 & D1 as closely as possible.
Typical PC Board Layout:
Top Side Layout Guide
Bottom Side Layout Guide
RI
ESR
AP5004
Document number: DS31444 Rev. 5 - 2
9 of 11
www.diodes.com
August 2010
© Diodes Incorporated
Ordering Information
AP5004
PWM CONTROL 2.5A STEP-DOWN CONVERTER
AP5004 S G - 13
Package
S : SOP-8L
Lead Free
G : Green
Packing
13 : Tape & Reel
Device
Package
Code
Packaging
(Note 4)
Quantity Part Number Suffix
AP5004SG-13 S SOP-8L 2500/Tape & Reel -13
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.
13” Tape and Reel
Marking Information
( Top View )
X
5
G : Green
: Year : 08, 09,10~
YY
WW : Week : 01~52; 52
represents 52 and 53 week
X
: Internal Code
41
Logo
Part Number
8
AP5004
WW X
YY
Package Outline Dimensions (All Dimensions in mm)
3.85/3.95
5.90/6.10
AP5004
Document number: DS31444 Rev. 5 - 2
7°~9°
1.27typ
8x-0.60
6x-1.27
8x-1.55
Land Pattern Recommendation
0.3/0.5
4.85/4.95
(Unit: mm)
0.10/0.20
0.15/0.25
1.30/1.50
1.75max.
5.4
10 of 11
www.diodes.com
Detail "A"
0.35max.
0.62/0.82
45°
7°~9°
0.254
Gauge Plane
Seating Plane
Detail "A"
0°/8°
August 2010
© Diodes Incorporated
AP5004
PWM CONTROL 2.5A STEP-DOWN CONVERTER
IMPORTANT NOTICE
DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS
DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION).
Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other
changes without further notice to this document and any product described herein. Diodes Incorporated does not assume any liability
arising out of the application or use of this document or any product described herein; neither does Diodes In corporated convey any
license under its patent or trademark rights, nor the rights of others. Any Customer or user of this documen t or products described
herein 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 Diodes Incorporated website, harmless against all damages.
Diodes Incorporated does not warrant or accept any liability whatsoever in respect of any products purchased through unauthorized
sales channel.
Should Customers purchase or use Diodes Incorporated products for any unintended or unauthorized application, Customers shall
indemnify and hold Diodes Incorporated and its representatives harmless against all claims, damages, expenses, and attorney fees
arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized application.
Products described herein may be covered by one or more United States, international or foreign p atents pending. Product names
and markings noted herein may also be covered by one or more United States, international or foreign trademarks.
LIFE SUPPORT
Diodes Incorporated products are specifically not authorized for use as critical components in life support devices 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 b e reasonably expected
to cause the failure of the life support device or to affect its safety or effectiveness.
Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support dev ices or
systems, and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements
concerning their products and any use of Diodes Incorporated products in such safety-critical, life support devices or systems,
notwithstanding any devices- or systems-related information or support that may be provided by Diodes Incorporated. Further,
Customers must fully indemnify Diodes Incorporated and its representatives against any damages arising out of the use of Diodes
Incorporated products in such safety-critical, life support devices or systems.
Copyright © 2010, Diodes Incorporated
www.diodes.com
AP5004
Document number: DS31444 Rev. 5 - 2
11 of 11
www.diodes.com
August 2010
© Diodes Incorporated
Loading...