Diodes AP1520 User Manual

AP1520

PWM CONTROL 2A 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

• 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

General Description

AP1520 consists of step-down switching regulator with PWM
control. These devices include a reference voltage source,
oscillation circuit, error amplifier and internal PMOS.

AP1520 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,
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 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

IN

R

OCSET

3K

C

IN

680uF

CVcc

0.1uF

R

100K

C

0.1uF

C

OCSET

Option

EN

EN

V

cc

OCSET

Note: V
R

AP1520

EN

OUT

=0.7K~5K ohm

B

Output

FB

V

SS

= VFB x (1+RA/RB)

L1

22uH

Optional

D1

V

OUT

R

C

C

A

6.8K

R

B

1.3K

+

+

C

0.1uF 470uF

-

-

C

OUT

AP1520 Rev. 5 1 of 9 JULY 2009
DS31174 www.diodes.com © Diodes Incorporated

Ordering Information

PWM CONTROL 2A STEP-DOWN CONVERTER

AP1520 S X - 13

AP1520

Package Packing

Device

AP1520SL-13 S SOP-8L 2500/Tape & Reel -13

Lead-free

AP1520SG-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.

http://www.diodes.com/datasheets/ap02001.pdf.

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

V

CC

1

2

AP1520

3

4

8

7

6

5

Vss

Vss

Output

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

AP1520 Rev. 5 2 of 9 JULY 2009
DS31174 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

Block Diagram

AP1520

PWM CONTROL 2A STEP-DOWN CONVERTER

Output

Oscillation

Circuit

V

cc

PWM-Switched
Control Circuit

Reference Voltage

Source with Soft Start

+

-

Thermal

Shutdown

EN

EN

100uA

OCSET

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 -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.

- 0.3 to VSS + 25 V

SS

- 0.3 to VCC V

SS

- 0.3 to VIN + 0.3 V

SS

Recommended Operating Conditions

Symbol Parameter Min Max Unit

VIN Input Voltage 4 23 V

I

Output Current 0 1.8 A

OUT

TA Operating Ambient Temperature -25 85

FB

VssV

o

C

o

C

o

C

AP1520 Rev. 5 3 of 9 JULY 2009
DS31174 www.diodes.com © Diodes Incorporated