Diodes AP1510 User Manual

AP1510

PWM CONTROL 3A STEP-DOWN CONVERTER

Features

• Input voltage: 3.6V to 23V

• Output voltage: 0.8V to V

• Duty ratio: 0% to 100% PWM control

• Oscillation frequency: 300kHz typ.

• Current Limit, Enable function

• Thermal Shutdown function

• Built-in internal SW P-channel MOS

• SOP-8L Pb-Free Package

• SOP-8L: Available in “Green” Molding Compound

(No Br, Sb)

• Lead Free Finish/ RoHS Compliant (Note 1)

.

CC

Applications

• Cellular Phones

• 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

C

IN

470uF

R

3.9K

CVcc

0.1uF

OCSET

C Option

R

EN

100K

C

EN

0.1uF

OCSET

Vcc

OCSET

EN

AP1510

General Description

AP1510 consists of step-down switching regulator with PWM control. These devices include a reference voltage source, oscillation circuit, error amplifier and internal PMOS.

AP1510 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. An enable function, an over current protection and a short circuit protection are built inside, 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 package, providing such outstanding features as low current consumption. Since this converter can accommodate an input voltage up to 23V, it is also suitable for the operation via an AC adapter.

V

=5V/3A

Output

FB

V

SS

L1

22uH

C

Optional

D1

R

C

A

6.8K

R

B

1.3K

OUT

+

C

0.1uF 470uF

-

C

OUT

Note: V R

= VFB x (1+RA/RB)

OUT

=0.7K~5K ohm

B

AP1510 Rev. 7 1 of 9 JULY 2009 DS31018 www.diodes.com © Diodes Incorporated

Ordering Information

PWM CONTROL 3A STEP-DOWN CONVERTER

AP1510 S X - 13

AP1510

Package Packing

Device

AP1510SL-13 S SOP-8L 2500/Tape & Reel -13

Lead-free

AP1510SG-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/datasheets/ap02001.pdf.

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

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 Assignments

( Top View )

FB

EN

OCSET

CC

V

1

2

AP1510

3

4

8

7

6

5

Vss

Output

SOP-8L

Pin Descriptions

Pin Name Pin NO. Description

FB 1 Feedback pin.

Enable Input pin H: Normal operation

EN 2

OCSET 3 Add an external resistor to set max output current.

VCC 4 IC power supply pin

Output 5, 6

VSS 7, 8 GND Pin

AP1510 Rev. 7 2 of 9 JULY 2009 DS31018 www.diodes.com © Diodes Incorporated

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

Switch Pin. Connect external inductor/diode here. Minimize trace area at this pin to reduce EMI.

y

Block Diagram

AP1510

PWM CONTROL 3A STEP-DOWN CONVERTER

Output

Oscillation

Circuit

Reference Voltage

Source with Soft Start

Vcc

PWM-Switched Control Circuit

+

FB

-

Thermal

Shutdown

EN

100uA

OCSET

VssV

Absolute Maximum Ratings

Symbol Parameter Rating Unit

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 Internall

D

T

Operating Junction Temperature Range -20 to +125

OP

T

Storage Temperature Range -65 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 VSS + 25 V

CC

- 0.3 to VCC V

SS

- 0.3 to VIN + 0.3 V

SS

limited mW

o

C

o

C

Recommended Operating Conditions

Symbol Parameter Min Max Unit

VIN Input Voltage 3.6 23 V

I

Output Current 0 3 A

OUT

TA Operating Ambient Temperature -25 85

o

C

AP1510 Rev. 7 3 of 9 JULY 2009 DS31018 www.diodes.com © Diodes Incorporated

AP1510

PWM CONTROL 3A STEP-DOWN CONVERTER

Electrical Characteristics (VIN = 12V, T

= 25°C, unless otherwise specified)

a

Symbol Parameter Conditions Min Typ. Ma. Unit

VFB Feedback Voltage I

IFB Feedback Bias Current I

ISW Switch Current -- 3.5 - - A

I

∆V

/V

f

I

OCSET

Current Consumption During

SHDN

Power Off

OUT

Line Regulation V

/VIN

OUT

Load Regulation I

OUT

f

Oscillation Frequency Measure waveform at SW pin 240 300 360 kHz

OSC

Frequency of Current Limit or

OSC1

Short Circuit Protect

VIH

EN Pin Input Voltage

VIL Evaluate oscillation stop at SW pin - - 0.8

I

ENH

EN Pin Input Leakage Current

I

-- - -10 - µA

ENL

OCSET Pin Bias Current -- 75 90 105 µA

TSS Soft-Start Time -- 0.3 2 5 ms

T

Thermal shutdown threshold - 150 - °C

SHDN

T

Thermal shutdown hysteresis - 55 - °C

HYS

R

Internal MOSFET Rdson

DSON

EFFI Efficiency

Thermal Resistance

θJA

Junction-to-Ambient Thermal Resistance

θJC

Junction-to-Case

Notes: 3. Test condition: Device mounted on FR-4 substrate 2oz copper, minimum recommended pad layout, single side.

For better thermal performance, please arrange larger copper pad of layout for heatsink.

= 0.1A 0.784 0.8 0.816 V

OUT

= 0.1A - 0.1 0.5 µA

OUT

VEN = 0V - 10 - µA

= 5V~23V, I

IN

= 0.1 to 3A - 0.2 0.5 %

OUT

= 0.2A - 1 2 %

OUT

Measure waveform at SW pin 10 - - kHz

Evaluate oscillation at SW pin 2.0 - -

V

-- - 20 - µA

V

= 5V, VFB= 0V - 110 150

IN

V

=12V, VFB= 0V - 70 100

IN

= 12V, V

V

IN

I

= 3A

OUT

= 5V

- 91 - %

SOP-8L (Note 3) - 134 -

SOP-8L (Note 3) - 22 -

mΩ

o

C/W

o

C/W

AP1510 Rev. 7 4 of 9 JULY 2009 DS31018 www.diodes.com © Diodes Incorporated

)

AP1510

PWM CONTROL 3A STEP-DOWN CONVERTER

Typical Performance Characteristics

AP1510 Vin vs. Frequency

350 345 340 335 330 325 320

Fosc (kHz)

315 310 305 300

(Vout=3.3V; Iout=0.2A)

0 5 10 15 20 25

AP1510 Line Re gul ation

3.40

3.35

3.30

3.25

Vout(V)

3.20

3.15

3.10

(Vout=3.3V; Iout=0.2A)

0 5 10 15 20 25

Vi n ( V)

Vin (V)

AP1510 V in 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)

0 5 10 15 20 25

Vin ( V)

AP1510 Load Regul ation

5.10

5.09

5.08

5.07

5.06

5.05

5.04

Vout (A

5.03

5.02

5.01

5.00

0.01.02.03.04.0

(Vin=12V)

Iout (A)

AP1510 Effici ency

100

90

80 70

60 50

40 30

Efficiency (%)

20

10

0

0.0 1.0 2.0 3.0

Vout:5.0V

Vout:3.3V

Iout (A)

AP1510 Rev. 7 5 of 9 JULY 2009 DS31018 www.diodes.com © Diodes Incorporated

V

A

PWM CONTROL 3A STEP-DOWN CONVERTER

Typical Performance Characteristics (Continued)

AP1510

(Vin=12V; Vout=3.3V; Iout=0.1A)

out Ripple

(Vin=12V; Vout=3.3V; Iout=3A)

AP1510

P1510 Vout Ripple

Test Circuit

open

OUTPUT OUTPUT

VCC

OCSET

A

EN

VSS

FB

Enable function test

OUTPUT

VCC

+

-

OCSET

EN

FB

VSS

open

A

Oscillation

VCC

+

OCSET EN

-

FB

VSS

Feedback function test

V

+

-

Operation function test

AP1510

PWM CONTROL 3A STEP-DOWN CONVERTER

Functional Description

PWM Control

The AP1510 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 AP1510 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

II

OUT(MAX)PEAK

−

+>

VV

Lfs

×

2

V

OUTOUTIN

V

IN

DS (ON)

is recommended.

OCSET

is the MOSFET ON

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 3A, ∆I the inductor should be at least equal to the maximum load current plus half the ripple current to prevent core saturation (3A+0.225A).

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

I

ΔIV

ESR

×=

LRIPPLE

.

FB

V

IN

Δ×

=0.45A. The DC current rating of

Marking Information

(1) SOP-8L

AP1510

PWM CONTROL 3A STEP-DOWN CONVERTER

( Top View )

Logo

Part Number

Package Information

(1) Package type: SOP-8L

7°~9°

1.27typ

0.3/0.5

4.85/4.95

8

5

AP1510

WW X

YY

(All Dimensions in mm)

3.85/3.95

5.90/6.10

0.10/0.20

Detail "A"

0.35max.

0.15/0.25

1.30/1.50

1.75max.

X

41

0.62/0.82

45°

7°~9°

0.254

Gauge Plane

Seating Plane

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)

AP1510

PWM CONTROL 3A STEP-DOWN CONVERTER

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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

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