Diodes AP1501 User Manual

AP1501

150KHz, 3A PWM BUCK DC/DC CONVERT ER

Features

• Output voltage: 3.3V, 5V, 12V and adjustable output version

• Adjustable version output vo l tag e range, 1.23V to

• 150KHZ +

• Voltage mode non-synchronous PWM control

• Thermal-shutdown and current-limit protection

• ON/OFF shutdown control input

• Operating voltage can be up to 40V

• Output load current: 3A

• Low power standb y mode

• Built-in switching transistor on chip

• Lead Free packages: TO263-5L and TO220-5L(R)

• TO263-5L and TO220-5L(R): Available in “Green”

• Lead Free Finish/RoHS Compliant (Note 1)

4%

37V+

Molding Compound (No Br, Sb)

15% fixed switching frequency

Applications

• Simple High-efficiency step-down regulator

• On-card switching regulators

• Positive to negative converter

General Description

The AP1501 is a fully integrated step-down DC/DC converter, with the ability to drive 3A load without the need of additional driver components. The AP1501 operates at a switching frequency of 150KHZ enabling the use of small size filter components. As a result, board space is reduced and BOM costs are lowered.

The AP1501 has integrated the shutdown function that allows standby mode to be activated via an external logic signal input. The internal compensation facilitates feedback control for line and load regulation without the need of an external circuitry. The AP1501 has a built-in Thermal shutdown and Current Limit function to prevent damage from high operating temperature and high current operating to the output switch.

Additional features include a guaranteed +/- 4% tolerance on the output voltage under specified input and output load conditions, and +/- 15% on oscillator frequency. The AP1501 offers both fixed and a Adjustable output voltages. For fixed outputs the AP1501 supports 3.3V, 5.0V and 12V. The package options available are standard 5-lead TO263 and TO220(R) packages.

Ordering Information

AP1501 - XX

Output version

Blank : Adjustable

33 : 3.3V 50 : 5.0V

Package

K5 : TO263-5L T5 : TO220-5L

T5R : TO220-5L(R)

12 : 12V

Device

Lead-free

AP1501-XXK5L-U K5 TO263-5L 50 -U NA NA

Lead-free

AP1501-XXK5L-13 K5 TO263-5L NA NA 800/Tape & Reel -13 AP1501-XXK5G-U K5 TO263-5L 50 -U NA NA AP1501-XXK5G-13 K5 TO263-5L NA NA 800/Tape & Reel -13 AP1501-XXT5L-U T5 TO220-5L 50 -U NA NA

Lead-free

AP1501-XXT5G-U T5 TO220-5L 50 -U NA NA AP1501-XXT5RL-U T5R TO220-5L(R) 50 -U NA NA

Lead-free

AP1501-XXT5RG-U T5R TO220-5L(R) 50 -U NA NA

Notes: 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied, see EU Directive 2002/95/EC Annex Notes.

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)

AP1501 Rev. 11 1 of 12 JANUARY 2009

XXX X - X

Lead Free

L : Lead Free

G : Green

Packing

U : Tube

13 : Tape & Reel

Tube 13” Tape and Reel

Quantity Part Number

Suffix

.

Quantity Part Number

Suffix

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Pin Assignments

( Top View )

AP1501

150KHz, 3A PWM BUCK DC/DC CONVERT ER

( Top View )

5 SD 4 FB 3 Gnd 2 Output

1 V

Metal Tab GND

TO263-5L

Pin Descriptions

Name Description

VIN Operating voltage input

Output Switching output

Gnd Ground

FB Output voltage feedback control SD ON/OFF shutdown

5 SD 4 FB 3 Gnd 2 Output 1 V

IN

TO220-5L/TO220-5L(R)

IN

AP1501 Rev. 11 2 of 12 JANUARY 2009

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Block Diagram

Current Source

bias

1.235V

Reference

2.5V

Regulator

AP1501

150KHz, 3A PWM BUCK DC/DC CONVERT ER

SD

V

IN

220mV200mV

Start

up

+

Comp

_

Comp

+

FB

+ _

Amp

Frequency

compen-

sation

_

Comp +

150kHz

OSC.

Pre-driver

Thermal

Shutdown

3A

Switch

Absolute Maximum Ratings

Symbol Parameter Rating Unit

ESD MM Machine Model ESD Protection 400 V

VCC Supply Voltage +45 V VSD ON/OFF Pin input Voltage -0.3 to +40 V VFB Feedback Pin Voltage -0.3 to +40 V

V

Output Voltage to Ground -1 V

OUT

PD Power Dissipation Internally limited W

TST Storage Temperature -65 to +150

TJ Operating Junction Temperature -20 to +125

T

MJ

Maximum Junction Temperature 150

Output

Gnd

o

C

o

C

oC

AP1501 Rev. 11 3 of 12 JANUARY 2009

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f

(reg

)

AP1501

150KHz, 3A PWM BUCK DC/DC CONVERT ER

Recommended Operating Conditions

Symbol Parameter

Rating

VOP Operating Voltage 4.5 to 40 V

TA Oper at i n g Am bi ent Temperatur e -20 to 85

Electrical Characteristics (All Output Voltage Versions)

Unless otherwise specified, V Specifications with boldface type are for full operating temperature range, the other type are for T

Symbol Parameter Conditions Min Typ. Max Unit

IFB Feedback Bias Current

F

Oscillator Frequency

OSC

V

Saturation Voltage

SAT

DC

Max. Duty Cycle(ON) Min. Duty cycle(OFF)

ICL Current Limit

Output = 0

IL

Output = -1

IQ Quiescent Current

I

STBY

VIH

Standby Quiescent Current

VIL

ON/OFF pin Logic Input Threshold Voltage

ON/OFF Pin Logic

IH

Input Current ON/OFF Pin Input

IL

Current

= 12V for 3.3V, 5V, adjustable version and V

IN

= 1.3V

V

FB

(Adjustable version only)

I

= 3A

OUT

No outside circuit

= 0V force driver on

V

FB

V

= 0V force driver on 100

FB

V

= 12V force driver off 0

FB

Peak current no outside circuit

= 0V force driver on

V

FB

Output Leakage Current

No outside circuit

= 12V force driver off (Note 3)

V

FB

= 40V 2 60

V

IN

= 12V force driver of

V

FB

ON/OFF pin = 5V

= 40V

V

IN

Low

ulator ON

High (regulator OFF) 2.0

= 2.5V (OFF) 15 25

V

LOGIC

= 0.5V (ON) 0.02 5

V

LOGIC

= 24V for the 12V version. I

IN

J

40

127 150 173

110 173

1.3

3.6 4.0

200

150

= 0.5A

LOAD

= 25ºC.

5 10

1.3

60

100

1.4

1.5

5.5

6.5

250

350

0.6

Units

o

C

KHZ

nA

%

uA

mA mA

uA

V

A

V

θ

Notes: 3 . Feedback pin removed from output and connected to 0V to force the output transistor switch ON. Feedback pin rem oved from output and

Thermal Resistance

JA

unction to Ambient

Thermal Resistance

JC

Junction to Case

connected to 12V for the 3.3V, 5V, and the ADJ. version, and 15V for the 12V version, to force the output transistor switch OFF.

4. Test condition: Device mounted with copper area of approximately 3 in

TO263-5L (Note 4) 37 TO220-5L(R) (Note 4) 31

TO263-5L (Note 4) 6

TO220-5L(R) (Note 4) 5

2

,1oz, no air flow.

o

C/W

o

C/W

AP1501 Rev. 11 4 of 12 JANUARY 2009

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150KHz, 3A PWM BUCK DC/DC CONVERT ER

Electrical Characteristics (Continued)

Specifications with boldface type are for full operating temperature range, the other type are for TJ = 25ºC.

AP1501-ADJ

AP1501-3.3V

AP1501-5V

AP1501-12V

Symbol Parameter Conditions V

VIN < 40V

V

FB

η

V

OUT

η

V

OUT

η

V

OUT

η

Output

Feedback

Efficiency V

Output Voltage

Efficiency V

Output Voltage

Efficiency V

Output Voltage

Efficiency V

4.5V <

0.2A < I V

OUT

= 12V, I

IN

4.75V <

0.2A < = 12V, I

IN

7V <

0.2A < = 12V, I

IN

15V <

0.2A < = 15V, I

IN

< 3A

LOAD

programmed for 3V

LOAD

VIN < 40V

I

< 3A

LOAD

VIN < 40V

I

< 3A

LOAD

VIN < 40V

I

< 3A

LOAD

= 3A 73 %

= 3A 80 %

= 3A 90 %

Typ. V

Min

1.193

1.18

1.23

3.168

3.135

4.8

4.75

11.52

11.4

3.3

5

12

AP1501

Unit

Max

1.267

1.28

3.432

3.465

5.2

5.25

12.48

12.6

V

AP1501 Rev. 11 5 of 12 JANUARY 2009

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s

150KHZ, 3A PWM BUCK DC/DC CONVERTER

Typical Performance Characteristics

Typical Performance Characteristic

Normalized Output Voltage

AP1501

Efficiency

OUTPUT VOLTAGE (V)

SATURATION VOLTAGE (V)

5.10

5.05

5.00

4.95

4.90

-50 -25 0 25 50 75 100 125

JUNCTION TEMPERATURE(oC)

VIN=20V, I Normalized at T

Switch Saturation Voltage

1.60

1.40

1.20

1.00

0.80

0.60

1 : -40oC 2 : 25 3 : 125

1 2

3

0.5

o

C

o

C

1

SWITCH CURRENT(A)

23

LOAD

=3A

=25oC

J

100

95 90

85

80

EFFICIENCY (%)

75

70 65

5V

3.3V

8101520253035

JUNCTION TEMPERATURE(oC)

3A Load

40

Switch Current Limit

5.50

VIN=12V, V

5.00

4.50

4.00

SWITCH CURRENT LIMIT (A)

3.50

-50 -25 0 25 50 75 100 125

JUNCTION TEMPERATURE(

OUT

=5V

o

C)

Operating Quiescent Current

25.0

20.0

15.0

10.0

5.0

SUPPLY CURRENT (mA)

0.0

-50 -25 0 25 50 75 100 125

JUNCTION TEMPERATURE(oC)

Switch ON

Switch OFF

200.0

160.0

120.0

CURRENT (uA)

Shutdown Quiescent Current

1 2

80.0

40.0

0.0

3

10 20 30 40

SUPPLY VOLOTAGE (V)

V

ON/OFF

1 : -40 2 : 25 3 : 125

o o

o

=5V C C

C

AP1501 Rev. 11 6 of 12 JANUARY 2009

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150KHz, 3A PWM BUCK DC/DC CONVERT ER

Typical Performance Characteristics (Continued)

Minimum Operating Supply Voltage

5.0

AP1501

ON/OFF Threshold Voltage

4.0

3.0

2.0

V

1.0

SUPPLY VOLTAGE (V)

0.0

OUT

I

LOAD

-50 -25 0 25 50 75 100 125

JUNCTION TEMPERATURE (oC)

ON/OFF Pin Current (Sinking)

150.0

120.0

90.0

60.0

CURRENT (uA)

30.0

VIN=40V

-40

0.0

1.45 10152022232425

=1.23V =120mA

o

C TJ 125oC

≤≤

ON/OFF PIN VOLTAGE (V)

4.0

3.0

2.0

1.0

THRESHOLD VOLTAGE (V)

0.0

-50

0

-25

JUNCTION TEMPERATURE (oC)

Switch Frequency

200.0

150.0

100.0

50.0

FREQUENCY (kHz)

0.0

-50 -25 0 25 50 75 100 125

JUNCTION TEMPERATURE (oC)

25 50 75

100 125

Feedback Pin Bias Current

50.0

40.0

30.0

20.0

Adjustable Version Only

BIAS CURRENT (nA)

10.0

0.0

-50 -25 0 25 50 75 100 125

o

JUNCTION TEMPERATURE(

C)

AP1501 Rev. 11 7 of 12 JANUARY 2009

×

Typical Application Circuit

(1) Fixed Type Circuit

12V

DC Input

12

Vin

Cin

Capacitor

(2) Adjustable Type Circuit

FB

4

AP1501

-33

SD

R2

35

Gnd

AP1501

150KHz, 3A PWM BUCK DC/DC CONVERT ER

Output

L1

33uH

Inductor

D1

B340A

R1

3.3V/3A

Output Load

Co

Capacitor

12V

DC Input

Cin

Capacitor

(3) Delay Start Circuit

12V

DC Input

Cin

Capacitor

FB

4

12

Vin

AP1501

SD

V V

= V

out

= 1.23V

FB

R2 = 1K ~ 3K

R2

FB

4

12

AP1501

SD

R

DELAY

10K

C

DELAY

0.1uF

Vin

L1

Output

35

Gnd

47uH

D1

(Note 5)

5V/ 3A

Output Load

Co

Capacitor

R1

(1 +

FB

Output

35

Gnd

R2

)

R1

47uH

D1

(Note 5)

L1

5V/ 3A

Output Load

Co

Capacitor

Notes: 5. Suggested DIODES Power Schottky: B340A or PDS340 series.

AP1501 Rev. 11 8 of 12 JANUARY 2009

AP1501

150KHz, 3A PWM BUCK DC/DC CONVERT ER

Functional Description

Pin Functions +V

IN

This is the positive input supply for the IC switching regulator. A suitable input bypass capacitor must be present at this pin to minimize voltage transients and to supply the switching currents needed by the regulator.

Ground

Circuit ground.

Output

Internal switch. The voltage at this pin switches between (+V

) and approximately – 0.5V, with a duty cycle of

V

SAT

approximately V circuitry, the PC board copper area connected to this pin should be kept a minimum.

Feedback

Senses the regulated output voltage to complete the feedback loop.

ON/OFF

Allows the switching regulator circuit to be shutdown using logic level signals thus dropping the total input supply current to approximately 150uA. Pulling this pin below a threshold voltage of approximately 1.3V turns the regulator on, and pulling this pin above 1.3V (up to a maximum of 40V) shuts the regulator down. If this shutdown feature is not needed, the ON/OFF pin can be wired to the ground pin or it can be left open, in either case the regulator will be in the ON condition.

Thermal Considerations

The AP1501 is available in 5-pin surface mount TO-263 and TO-220.

The TO-220 package needs a heat sink under most conditions. The size of the heat sink depends on the input voltage , the output voltage, the load current and the ambient temperature. The AP1501 junction temperature rises above ambient temperature for a 3A load and different input and output voltages. The data for these curves was taken with the AP1501 (TO-220 package) operating as a buck switching regulator in an ambient temperature of 25 are all approximate and there are many factors that can affect these temperatures. Higher ambient temperatures require more heat sinking.

The TO-263 surface mount package tab is designed to be soldered to the copper on a printed circuit board. The copper and the board are the heat sink for this package and the other heat producing components, such as the catch diode and inductor. The PC board copper area that the package is soldered to should b e at least 0.4 in 2 or more square inches of 2 oz. Additional cop per area improv es the thermal characteristics, but with copper areas greater than approximately 6 in are realized. If further thermal improvements are needed, double sided, multilayer PC boards with large copper areas and/or airflow are recommended.

The AP1501 (TO-263 package) junction temperature rises above ambient temperature with a 2A load for various input and output voltages. This data was taken with the circuit operating as a buck switching regulator with all components mounted on a

/ VIN. To minimize coupling to sensitive

OUT

o

C (still air). These temperature rise numbers

2

, and ideally should have

2

, only small improvements in heat dissipation

IN

AP1501 Rev. 11 9 of 12 JANUARY 2009

PC board to simulate the junction temperature under actual operating conditions. This curve can be used for a quick check for the approximate junction temperature for various conditions, but be aware that there are many factors that can affect the junction temperature. When load currents higher than 2A are used, double sided or multilayer PC boards with large copper areas and/or airflow might be needed, especially for high ambient temperatures and high output voltages.

For the best thermal performance, wide copper traces and generous amounts of printed circuit board copper sh ou ld be used in the board layout. (One exception to this is the output (switch)

–

pin, which should not have large areas of copper.) Large areas of copper provide the best transfer of heat (lower thermal resistance) to the surrounding air, and moving air lowers the thermal resistance even further.

Package thermal resistance and junction temperature rise numbers are all approximate, and there are many factors that will affect these numbers. Some of these factors include board size, shape, thickness, position, location, and even board temperature. Other factors are, trace width, total printed circuit copper area, copper thickness, single or double-sided, multilayer board and the amount of solder on the board. The effectiveness of the PC board to dissipate heat also depends on the size, quantity and spacing of other components on the board, as well as whether the surrounding air is still or moving.

Furthermore, some of these components such as t he catch diode will add heat to the PC board and the heat can vary as the input voltage changes. For the inductor, depending on the physical size, type of core material and the DC resistance, it could either act as a heat sink taking heat away from the board, or it could add heat to the board.

Marking Information

(1) TO263-5L

AP1501

150KHz, 3A PWM BUCK DC/DC CONVERT ER

( Top View )

Logo

Output Type : 1501 : ADJ 1501-33 : 3.3V 1501-50 : 5.0V 1501-12 : 12V

(2) TO220-5L(R)

Output Type : 1501: ADJ 1501-33: 3.3V 1501-50: 5.0V 1501-12: 12V

1501-XX YY WW

( Top view )

X

1501-XX

YY WW X X

X

L : Lead Free

G : Green ID code

Xth week : 01~52 Year :

Logo

L : Lead Free

G : Green

ID code

Xth week : 01~52

Year : "07" = 2007

"07" = 2007 "08" = 2008

~

"08" = 2008

~

AP1501 Rev. 11 10 of 12 JANUARY 2009

Package Information

(1) Package Type: TO263-5L

AP1501

150KHz, 3A PWM BUCK DC/DC CONVERT ER

(2) Package Type: TO220-5L

AP1501 Rev. 11 11 of 12 JANUARY 2009

150KHz, 3A PWM BUCK DC/DC CONVERT ER

Package Information (Continued)

(3) Package Type: TO220-5L(R) Mechanical drawing

AP1501

IMPORTANT NOTICE

Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes without further notice to any product herein. Diodes Incorporated does not assume any liability arising out of the application or use of any product described herein; neither does it convey any license under its patent rights, nor the rights of others. The user of products 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 our website, harmless against all damages.

LIFE SUPPORT

Diodes Incorporated products are not authorized for use as critical components in life support devices or systems without the expressed written approval of the President of Diodes Incorporated.

AP1501 Rev. 11 12 of 12 JANUARY 2009