DIODES AP1513_09

AP1513
PWM CONTROL 2A STEP-DOWN CONVERTER
General Description
Features
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AP1513 consists of step-down switching regulator with PWM
control. These devices include a reference voltage source,
oscillation circuit, error amplifier, and internal PMOS.
Input voltage: 3.6V to 18V
Output voltage: 0.8V to VCC
Duty ratio: 0% to 100% PWM control
Oscillation frequency: 300KHz typ.
Soft-start, Current limit, Enable function
Thermal Shutdown function
Built-in internal SW P-channel MOS
SOP-8L: Available in “Green” Molding Compound
(No Br, Sb)
Lead Free Finish/ RoHS Compliant (Note 1)
AP1513 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 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 300KHz to 30KHz. 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 18V, it is also suitable for the operation via
an AC adapter.
Applications
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PC Motherboard
LCD Monitor
Graphic Card
DVD-Video Player
Telecom Equipment
ADSL Modem
Printer and other Peripheral Equipment
Microprocessor core supply
Networking power supply
Typical Application Circuit
Vcc
VIN
33uH
R OCSET COCSET
3K
Option
CIN
OCSET
470uF
CVcc
0.1uF
REN
100K
CC
Optional
AP1513
EN
FB
RA
6.8K
+
C
+
- 0.1uF-
VSS
D1
SBR2U30P1
CEN
0.1uF
VOUT = 5V/2A
L1
Output
COUT
470uF
RB
1.3K
Note: VOUT = VFB x (1+RA/RB)
RB =0.7K~5K ohm
VOUT
L1 Value
AP1513 Rev. 4
DS31053
VIN = 12V, IMAX = 2A
2.5V
3.3V
22uH
27uH
1 of 9
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5V
33uH
JULY 2009
© Diodes Incorporated
AP1513
PWM CONTROL 2A STEP-DOWN CONVERTER
Ordering Information
AP1513 S X - 13
AP1513SL-13
AP1513SG-13
Notes:
Lead Free
Packing
S : SOP-8L
L : Lead Free
G : Green
13 : Tape & Reel
Package
Code
S
S
Device
Lead-free
Package
13” Tape and Reel
Quantity
Part Number Suffix
2500/Tape & Reel
-13
2500/Tape & Reel
-13
Packaging
(Note 2)
SOP-8L
SOP-8L
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.
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.
Pin Descriptions
( Top View )
FB
1
EN
2
8 Vss
7 Vss
AP1513
OCSET 3
6
Output
VCC 4
5
Output
SOP-8L
Pin Descriptions
Pin Name
Pin No.
FB
1
EN
2
OCSET
VCC
3
4
Output
5, 6
VSS
7, 8
AP1513 Rev. 4
DS31053
Description
Feedback pin
Power-off pin
H: Normal operation
(Step-down operation)
L: Step-down operation stopped
(All circuits deactivated)
Add an external resistor to set max output current
IC power supply pin
Switch Pin. Connect external inductor/diode here. Minimize trace area at this pin
to reduce EMI
GND Pin
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JULY 2009
© Diodes Incorporated
AP1513
PWM CONTROL 2A STEP-DOWN CONVERTER
Block Diagram
Output
Oscillation
Circuit
Reference Voltage Source
Vcc
+
PWM-Switched
Control Circuit
FB
-
Thermal
Shutdown
VEN
EN
100uA
Vss
OCSET
Absolute Maximum Ratings
Symbol
Parameter
Rating
Unit
VSS - 0.3 to VSS + 20
V
VSS - 0.3 to VCC
V
EN Pin Voltage
VSS - 0.3 to VIN + 0.3
V
VOUT
Switch Pin Voltage
VSS - 0.3 to VIN + 0.3
V
PD
Power Dissipation
Internally limited
mW
TJ
Operating Junction Temperature Range
VCC
VCC Pin Voltage
VFB
Feedback Pin Voltage
VEN
TST
Caution:
Storage Temperature Range
-40 to +125
o
C
-40 to +150
o
C
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
VIN
IOUT
TA
AP1513 Rev. 4
DS31053
Parameter
Input Voltage
Output Current
Operating Ambient Temperature
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Min
3.6
0
-20
Max
18
2
85
Unit
V
A
o
C
JULY 2009
© Diodes Incorporated
AP1513
PWM CONTROL 2A STEP-DOWN CONVERTER
Electrical Characteristics
Symbol
VFB
IFB
ISW
ISSS
∆VOUT
/VOUT
∆VOUT
/VOUT
fOSC
fOSC1
VSH
VSL
ISH
ISL
IOCSET
TSS
RDSON
EFFI
θJA
θJC
Notes:
Parameter
Feedback Voltage
Feedback Bias Current
Switch Current
Current Consumption
During Power Off
(VIN = 12V, TA = 25°C, unless otherwise specified)
Conditions
Min.
0.784
2.5
Typ.
0.8
0.1
-
Max.
0.816
0.5
-
Unit
V
µA
A
VEN = 0V
-
10
-
µA
Line Regulation
VIN = 5V~18V
-
1
2
%
Load Regulation
IOUT = 0.1 to 2A
-
0.2
0.5
%
240
300
400
KHz
10
-
-
KHz
2.0
75
0.3
-
20
-10
90
2
110
70
0.8
105
5
150
100
-
92
-
-
134
-
o
C/W
-
22
-
o
C/W
IOUT = 0.1A
IOUT = 0.1A
--
Oscillation Frequency
Measure waveform at SW pin
Frequency of Current Limit
Measure waveform at SW pin
or Short Circuit Protect
Evaluate oscillation at SW pin
EN Pin Input Voltage
Evaluate oscillation stop at SW pin
-EN Pin Input Leakage
Current
-OCSET Pin Bias Current
-Soft-Start Time
-VIN = 5V, VFB = 0V
Internal MOSFET Rdson
VIN = 12V, VFB = 0V
VIN = 12V, VOUT = 5V
Efficiency
IOUT = 2A
Thermal Resistance
SOP-8L (Note 3)
Junction-to-Ambient
Thermal Resistance
SOP-8L (Note 3)
Junction-to-Case
V
µA
µA
µA
ms
mΩ
%
3. Test conditions: Device mounted on FR-4 PCB, 2"*2", 2oz copper minimum recommended pad layout, single-sided, PC boards.
AP1513 Rev. 4
DS31053
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JULY 2009
© Diodes Incorporated
AP1513
PWM CONTROL 2A STEP-DOWN CONVERTER
Typical Performance Characteristics
AP1513 Vin vs. Frequency
(Vout=3.3V; Iout=0.2A)
350
345
335
FB (V)
Fosc (KHz)
340
330
325
320
315
310
0
2
4
6
8 10 12
Vin (V)
14
16
18
20
Vout (V)
Vout (V)
3.35
3.30
3.25
3.20
3.15
3.10
0
2
4
6
8
0.84
0.83
0.82
0.81
0.80
0.79
0.78
0.77
0.76
0.75
0.74
0
AP1513 Line Regulation
(Vout=3.3V; Iout=0.2A)
3.40
AP1513 Vin vs. FB
(Vout=3.3V; Iout=0.2A)
10 12 14 16 18 20
Vin (V)
2
4
6
8
10
12 14
16 18
Vin (V)
20
AP1513 Load Regulation
(Vin=12V)
5.10
5.09
5.08
5.07
5.06
5.05
5.04
5.03
5.02
5.01
5.00
0.0
0.5
1.0
1.5
Iout (A)
2.0
2.5
AP1513 Efficiency
100
90
Efficiency (%)
80
70
60
50
40
30
Vout:5.0V
20
Vout:3.3V
10
0
0.0
0.5
1.0
1.5
2.0
Iout (A)
AP1513 Rev. 4
DS31053
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© Diodes Incorporated
AP1513
PWM CONTROL 2A STEP-DOWN CONVERTER
Typical Performance Characteristics
(Continued)
AP1513 Vout Ripple
( Vin = 12V; Vout = 3.3V; Iout = 0.1A )
AP1513 Vout Ripple
( Vin = 12V; Vout = 3.3V; Iout = 2A )
Test Circuit
VCC
1K
A
OUTPUT
FB
open
OCSET
EN
+
-
VCC
OUTPUT
VCC
OUTPUT
FB
1K
-
VSS
OCSET
EN
VSS
Feedback function test
33K
FB
6.8K
OCSET
EN
A
+
Enable function test
3K
Oscillation
open
+
VSS
-
V
1.2K
Operation function test
AP1513 Rev. 4
DS31053
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© Diodes Incorporated
AP1513
PWM CONTROL 2A STEP-DOWN CONVERTER
Functional Description
PWM Control
The AP1513 is a DC/DC converter that employs pulse width
modulation (PWM) scheme. Its pulse width varies in the range of
0% to 99%, based on the output current loading. The output
ripple voltage caused by the PWM high frequency switching can
easily be reduced through an output filter. Therefore, this
converter provides a low ripple output supply over a broad range
of input voltage & output current loading
Inductor Selection
For most designs, the operation range with inductors is from
22µH to 33µH. The inductor value can be derived from the
following equation:
Under Voltage Lockout
The under voltage lockout circuit of the AP1513 assures that the
high-side MOSFET driver remains in the off state whenever the
supply voltage drops below 3.3V. Normal operation resumes
once VCC rises above 3.5V.
Where ΔIL is inductor Ripple Current. Large value inductors lower
ripple current and small value inductors result in high ripple
current. Choose inductor ripple current approximately 15% of the
maximum load current 2A, ∆IL=0.30A. 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).
Current Limit Protection
The current limit threshold is set by external resistor ROCSET
connected from VCC supply to OCSET pin. The internal sink
current IOCSET (90μA typical) across this resistor sets the voltage
at OCSET pin. When the PWM voltage is less than the voltage at
OCSET, an over-current condition is triggered.
The current limit threshold is given by the following equation:
IPEAK × R DS(ON) = IOCSET × R OCSET
VIN − VOUT VOUT
×
fs × ΔI
VIN
Input Capacitor Selection
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.
Output Capacitor Selection
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.
(ΔI)
IPEAK > IOUT(MAX) + 2
where,
ΔI =
L=
VIN − VOUT VOUT
×
fs × L
VIN
V RIPPLE = ΔIL × ESR
IPEAK is the output peak current; RDS (ON) is the MOSFET ON
resistance; fS is the PWM frequency (300KHz typical). Also, the
inductor value will affect the ripple current ΔI.
The above equation is recommended for input voltage range of
5V to 18V. For input voltage lower than 5V or ambient
temperature over 100°C, higher ROCSET is recommended.
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.
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 evaluation board should be
allowed for maximum copper area at output (SW) pins.
1.
2.
3.
4.
AP1513 Rev. 4
DS31053
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Connect FB circuits as closely as possible and keep away
from inductor flux for pure VFB.
Connect input capacitor to Vcc and Vss pin as closely as
possible to get good power filter effect.
Connect ROCSET to Vcc and OCSET pin as closely as
possible.
Connect ground side of the input capacitor & Schottky &
output capacitor as closely as possible and use ground
plane for best performance.
JULY 2009
© Diodes Incorporated
AP1513
PWM CONTROL 2A STEP-DOWN CONVERTER
Marking Information
(1) SOP-8L
( Top View )
5
8
L : Lead Free
G : Green
YY : Year : 08, 09,10~
WW : Week : 01~52; 52
represents 52 and 53 week
X : Internal Code
Logo
AP1513
YY WW X X
Part Number
1
Package Information
4
(All Dimensions in mm)
0.254
0.10/0.20
3.85/3.95
5.90/6.10
(1) Package type: SOP-8L
Gauge Plane
Seating Plane
0.62/0.82
Detail "A"
7°~9°
0.15/0.25
1.30/1.50
1.75max.
0.35max. 45°
7°~9°
Detail "A"
0°/8°
0.3/0.5
1.27typ
4.85/4.95
5.4
8x-0.60
8x-1.55
6x-1.27
Land Pattern Recommendation
(Unit: mm)
AP1513 Rev. 4
DS31053
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© Diodes Incorporated
AP1513
PWM CONTROL 2A STEP-DOWN CONVERTER
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DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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the express written approval of the Chief Executive Officer of Diodes Incorporated. As used herein:
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B.
A critical component is any component in a life support device or system whose failure to perform can be reasonably expected
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Customers must fully indemnify Diodes Incorporated and its representatives against any damages arising out of the use of Diodes
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Copyright © 2009, Diodes Incorporated
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AP1513 Rev. 4
DS31053
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© Diodes Incorporated