Diodes AP1513 User Manual

V

AP1513

PWM CONTROL 2A STEP-DOWN CONVERTER

Features

• Input voltage: 3.6V to 18V

• Output voltage: 0.8V to V

• 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)

CC

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

Typical Application Circuit

V

IN

R

C

OCSET

Option

R

EN

100K

C

EN

0.1uF

C

IN

470uF

3K

CVcc

0.1uF

Vcc

OCSET

EN

AP1513

General Description

AP1513 consists of step-down switching regulator with PWM control. These devices include a reference voltage source, oscillation circuit, error amplifier, and internal PMOS.

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.

V

C

0.1uF

OUT

+

-

= 5V/2A

C

OUT

470uF

Output

FB

V

SS

L1

33uH

C

Optional

D1

SBR2U30P1

R

A

6.8K

R

B

1.3K

+

-

Note: V R

OUT

L1 Value

22uH 27uH 33uH

= VFB x (1+RA/RB)

OUT

=0.7K~5K ohm

B

=12V, I

IN

=2A

MAX

2.5V 3.3V 5V

AP1513 Rev. 4 1 of 9 JULY 2009 DS31053 www.diodes.com © Diodes Incorporated

Ordering Information

PWM CONTROL 2A STEP-DOWN CONVERTER

AP1513 S X - 13

AP1513

Package Packing

Device

AP1513SL-13 S SOP-8L 2500/Tape & Reel -13

Lead-free

AP1513SG-13 S SOP-8L 2500/Tape & Reel -13

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.

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.

Package

Code

Packaging

(Note 2)

Lead Free

L : Lead Free

G : Green

13 : Tape & ReelS : SOP-8L

13” Tape and Reel

Quantity Part Number Suffix

Pin Descriptions

FB

EN

OCSET

V

CC

( Top View )

1

2

AP1513

3

4

8

7

6

5

Vss

Output

SOP-8L

Pin Descriptions

Pin Name

Pin No.

FB 1 Feedback pin

Power-off pin H: Normal operation

EN 2

(Step-down operation) L: Step-down operation stopped (All circuits deactivated)

OCSET 3 Add an external resistor to set max output current

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

AP1513 Rev. 4 2 of 9 JULY 2009 DS31053 www.diodes.com © Diodes Incorporated

Description

Block Diagram

AP1513

PWM CONTROL 2A STEP-DOWN CONVERTER

Output

Oscillation

Circuit

Reference Voltage Source

Vcc

PWM-Switched Control Circuit

+

FB

-

Thermal

Shutdown

EN

100uA

OCSET

VssV

Absolute Maximum Ratings

Symbol Parameter Rating Unit

V

VCC Pin Voltage V

CC

V

Feedback Pin Voltage V

FB

V

EN Pin Voltage V

EN

V

Switch Pin Voltage VSS - 0.3 to VIN + 0.3 V

OUT

P

Power Dissipation Internally limited mW

D

T

Operating Junction Temperature Range -40 to +125

J

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.

- 0.3 to VSS + 20 V

SS

- 0.3 to VCC V

SS

- 0.3 to VIN + 0.3 V

SS

o

C

o

C

Recommended Operating Conditions

Symbol Parameter Min Max Unit

VIN Input Voltage 3.6 18 V

I

Output Current 0 2 A

OUT

TA Operating Ambient Temperature -20 85

o

C

AP1513 Rev. 4 3 of 9 JULY 2009 DS31053 www.diodes.com © Diodes Incorporated

AP1513

PWM CONTROL 2A STEP-DOWN CONVERTER

Electrical Characteristics (VIN = 12V, T

= 25°C, unless otherwise specified)

A

Symbol Parameter Conditions Min. Typ. Max. Unit

VFB Feedback Voltage I

IFB Feedback Bias Current I

= 0.1A 0.784 0.8 0.816 V

OUT

= 0.1A - 0.1 0.5 µA

OUT

ISW Switch Current -- 2.5 - - A

I

SSS

∆V

/V

∆V

/V

f

OSC

f

OSC1

VSH

VSL Evaluate oscillation stop at SW pin - - 0.8

ISH

ISL -- - -10 - µA

I

OCSET

Current Consumption During Power Off

OUT

Line Regulation V

OUT

Load Regulation I

OUT

V

= 0V - 10 - µA

EN

= 5V~18V - 1 2 %

IN

= 0.1 to 2A - 0.2 0.5 %

OUT

Oscillation Frequency Measure waveform at SW pin 240 300 400 KHz

Frequency of Current Limit or Short Circuit Protect

EN Pin Input Voltage

EN Pin Input Leakage

Measure waveform at SW pin 10 - - KHz

Evaluate oscillation at SW pin 2.0 - -

-- - 20 - µA

Current

OCSET Pin Bias Current -- 75 90 105 µA

V

TSS Soft-Start Time -- 0.3 2 5 ms

V

= 5V, VFB= 0V - 110 150

R

Internal MOSFET Rdson

DSON

EFFI Efficiency

θJA

θJC

Notes: 3. Test conditions: Device mounted on FR-4 PCB, 2"*2", 2oz copper minimum recommended pad layout, single-sided, PC boards.

Thermal Resistance Junction-to-Ambient Thermal Resistance Junction-to-Case

IN

V

= 12V, VFB= 0V - 70 100

IN

V I

OUT

IN

= 12V, V

= 2A

OUT

= 5V

- 92 - %

mΩ

SOP-8L (Note 3) - 134 - oC/W

SOP-8L (Note 3) - 22 - oC/W

AP1513 Rev. 4 4 of 9 JULY 2009 DS31053 www.diodes.com © Diodes Incorporated

PWM CONTROL 2A STEP-DOWN CONVERTER

Typical Performance Characteristics

AP1513 Vin vs. Frequency

350

345

340

335

330

325

Fosc (KHz)

320

315

310

(Vout=3.3V; Iout=0.2A)

0 2 4 6 8 10 12 14 16 18 20

Vin (V)

AP1513

AP1513 Vin vs. FB

0.84

0.83

0.82

0.81

0.80

0.79

FB (V)

0.78

0.77

0.76

0.75

0.74

(Vout=3.3V; Iout=0.2A)

02468101214161820

Vin (V)

AP1513 Line Re gulation

3.40

3.35

3.30

3.25

Vout (V)

3.20

3.15

3.10

(Vout=3.3V; Iout= 0.2A)

0 2 4 6 8 10 12 14 16 18 20

Vin (V)

AP1513 Efficiency

100

90

80

70

60

50

40

30

Efficiency (%)

20

10

0

0.0 0.5 1.0 1.5 2.0

Iout (A)

Vout:5.0V

Vout:3.3V

AP1513 Load Regulation

5.10

5.09

5.08

5.07

5.06

5.05

5.04

Vout (V)

5.03

5.02

5.01

5.00

0.0 0.5 1.0 1.5 2.0 2.5

(Vin=12V)

Iout (A)

AP1513 Rev. 4 5 of 9 JULY 2009 DS31053 www.diodes.com © Diodes Incorporated

PWM CONTROL 2A STEP-DOWN CONVERTER

Typical Performance Characteristics (Continued)

Ripple

out

= 3.3V; I

= 0.1A )

out

( V

in

= 12V; V

( V

AP1513 V

= 12V; V

in

out

AP1513 V

out

Ripple

out

= 3.3V; I

AP1513

= 2A )

out

Test Circuit

+

-

33K

A

Oscillation

6.8K

V

+

1.2K

-

1K

+

-

OCSET

EN

open

OUTPUT OUTPUT

1K

OCSET

A

EN

VSS

open

FBVCC

Enable function test Feedback function test

OUTPUT

VCC

3K

OCSET

EN

VSS

FB

FBVCC

VSS

Operation function test

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

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 V

Current Limit Protection

The current limit threshold is set by external resistor R connected from V current I 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:

where,

I resistance; f 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 R

rises above 3.5V.

CC

supply to OCSET pin. The internal sink

CC

(90μA typical) across this resistor sets the voltage

OCSET

I ×

=Δ

is the output peak current; R

PEAK

is the PWM frequency (300KHz typical). Also, the

S

OCSET

×=×

RIRI

OCSETOCSETDS(ON)PEAK

)I(Δ

VV

+>

Lfs

DS (ON)

OCSET

2

V

OUTOUTIN

V

IN

is the MOSFET ON

is recommended.

II

OUT(MAX)PEAK

−

×

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:

VV

L ×

Where ΔI ripple current and small value inductors result in high ripple current. Choose inductor ripple current approximately 15% of the maximum load current 2A, ∆I 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 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.

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 T 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. Connect FB circuits as closely as possible and keep away

2. Connect input capacitor to Vcc and Vss pin as closely as

3. Connect R

4. Connect ground side of the input capacitor & Schottky &

is inductor Ripple Current. Large value inductors lower

L

& TJ or large PD (Power Dissipation), The dual

C

from inductor flux for pure V

possible to get good power filter effect.

possible.

output capacitor as closely as possible and use ground plane for best performance.

OCSET

−

=

fs

L

to Vcc and OCSET pin as closely as

V

OUTOUTIN

Δ×

=0.30A. The DC current rating of

V

I

ΔIV

IN

ESR

×=

LRIPPLE

FB

.

Marking Information

(1) SOP-8L

AP1513

PWM CONTROL 2A STEP-DOWN CONVERTER

( Top View )

8

5

Logo

Part Number

AP1513

WW X

YY

X

41

Package Information (All Dimensions in mm)

(1) Package type: SOP-8L

0.254

0.62/0.82

7°~9°

Gauge Plane Seating Plane

7°~9°

1.27typ

4.85/4.95

0.3/0.5

3.85/3.95

5.90/6.10

1.30/1.50

1.75max.

0.15/0.25

0.10/0.20

0.35max.

Detail "A"

45°

L : Lead Free

G : Green

: Year : 08, 09,10~

YY WW : Week : 01~52; 52

represents 52 and 53 week

X

: Internal Code

Detail "A"

0°/8°

8x-0.60

5.4

6x-1.27

8x-1.55

Land Pattern Recommendation

(Unit: mm)

AP1513

PWM CONTROL 2A STEP-DOWN CONVERTER

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 Incorporated convey any license under its patent or trademark rights, nor the rights of others. Any Customer or user of this document 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.

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Products described herein may be covered by one or more United States, international or foreign patents pending. Product names and markings noted herein may also be covered by one or more United States, international or foreign trademarks.

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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 be 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 devices 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.

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IMPORTANT NOTICE

LIFE SUPPORT