Diodes AP6503A User Manual

A

C

0

240kHz 23V 2A SYNCHRONOUS DC/DC BUCK CONVERTER

high

Pin Assignments

( Top View )

BS

SW

GND

1

2

IN

3

4

SO-8EP

Figure 1. Package Pin Out

Applications

• Gaming Consoles

• Flat Screen TV Sets and Monitors

• Set Top Boxes

• Distributed Power Systems

• Home Audio

• Consumer Electronics

• Network Systems

• FPGA, DSP and ASIC Supplies

• Green Electronics

8

7

6

5

Description

The AP6503A is a 240kHz switching frequency external compensated synchronous DC/DC buck converter. It has integrated low R

DSON

and low side MOSFETs.

The AP6503A enables continues load current of up to 3A with efficiency as high as 95%.

The AP6503A features current mode control operation, which enables fast transient response times and easy loop stabilization.

The AP6503A simplifies board layout and reduces space requirements with its high level of integration and minimal need for external components, making it ideal for distributed power architectures.

The AP6503A is available in a standard Green SO-8EP package with exposed PAD for improved thermal performance and is RoHS compliant.

NEW PRODUCT

Features

• VIN 4.75V to 23V

• 3A continuous Output Current, 4A Peak

• V

• 240kHz switching frequency

• Programmable Soft-Start

• Enable pin

• Protection

• Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)

• Halogen and Antimony Free. “Green” Device (Note 3)

Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant.

2. See http://www.diodes.com for more information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green" and Lead-free.

3. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and <1000ppm antimony compounds

adjustable to 0.925 to 20V

OUT

 OCP  Thermal Shutdown

.

P6503A

SS

EN

COMP

FB

Typical Applications Circuit

10

90

V = 5V

80

Y (%)

70

IEN

60

EFFI

50

V = 3.3V

OUT

L = 10µH

40

0123

AP6503A

Document number: DS36000 Rev. 2 - 2

IN

V = 12V

IN

LOAD CURRENT (A)

Efficiency vs. Load Current

1 of 15

www.diodes.com

Figure 2. Typical Application Circuit

December 2012

A

Pin Descriptions

Number

Name

1 BS

2 IN

3 SW 4 GND Ground (Connect the exposed pad to Pin 4). 5 FB

6 COMP

7 EN

NEW PRODUCT

8 SS

EP EP EP exposed thermal pad connect to Pin 4 GND

Functional Block Diagram

P6503A

Function

High-Side Gate Drive Boost Input. BS supplies the drive for the high-side N-Channel MOSFET switch. Connect a

0.01µF or greater capacitor from SW to BS to power the high side switch. Power Input. IN supplies the power to the IC, as well as the step-down converter switches. Drive IN with a 4.75V

to 23V power source. Bypass IN to GND with a suitably large capacitor to eliminate noise on the input to the IC. See Input Capacitor.

Power Switching Output. SW is the switching node that supplies power to the output. Connect the output LC filter from SW to the output load. Note that a capacitor is required from SW to BS to power the high-side switch.

Feedback Input. FB senses the output voltage and regulates it. Drive FB with a resistive voltage divider connected to it from the output voltage. The feedback threshold is 0.925V. See Setting the Output Voltage.

Compensation Node. COMP is used to compensate the regulation control loop. Connect a series RC network from COMP to GND. In some cases, an additional capacitor from COMP to GND is required. See Compensation Components.

Enable Input. EN is a digital input that turns the regulator on or off. Drive EN high to turn on the regulator; low to turn it off. Attach to IN with a 100k pull up resistor for automatic startup.

Soft-Start Control Input. SS controls the soft-start period. Connect a capacitor from SS to GND to set the soft-start period. A 0.1µF capacitor sets the soft-start period to 15ms. To disable the soft-start feature, leave SS floating.

AP6503A

Document number: DS36000 Rev. 2 - 2

COMP

+

-

1.1V

0.3 V

0.923 V

0.9V

+

-

+ +

2.5V

+

-

5

FB

SS

8

6

EN

7

+

-

ERROR

AMPLIFIER

LOCKOUT

COMPARATOR

OVP

OSCILLATOR

80/240 KHz

EN OK

SHUTDOWN

RAMP

E

CLK

+

-

6uA

CURRENT

SENSE

AMPLIFIER

Logic

CURRENT

COMPARATOR

IN

INTERNAL

REGULATORS

+

-

IN < 4.10V

disable

100m

5V

IN

2

BS

1

SW

3

GND

4

Figure 3. Functional Block Diagram

2 of 15

www.diodes.com

December 2012

A

Absolute Maximum Ratings (@T

Symbol Parameter Rating Unit

VIN

VSW

VBS VFB

VEN

V

COMP

TST

TJ TL

ESD Susceptibility (Note 5)

HBM Human Body Model 3 kV

MM Machine Model 250 V

Notes: 4. Stresses greater than the 'Absolute Maximum Ratings' specified above may cause permanent damage to the device. These are stress ratings only;

NEW PRODUCT

functional operation of the device at these or any other conditions exceeding those indicated in this specification is not implied. Device reliability may be affected by exposure to absolute maximum rating conditions for extended periods of time.

5. Semiconductor devices are ESD sensitive and may be damaged by exposure to ESD events. Suitable ESD precautions should be taken when handling and transporting these devices.

Supply Voltage Switch Node Voltage Bootstrap Voltage Feedback Voltage -0.3V to +6 V Enable/UVLO Voltage -0.3V to +6 V Comp Voltage -0.3V to +6 V Storage Temperature -65 to +150 °C Junction Temperature +150 °C Lead Temperature +260 °C

= +25°C, unless otherwise specified.)

A

-0.3 to +26

-1.0 to V

V

-0.3 to VSW +6

SW

IN

+0.3

Thermal Resistance (Note 6)

Symbol Parameter Rating Unit



JA



JC

Note: 6. Test condition: SO-8EP: Device mounted on 1" x 1" FR-4 substrate PC board, 2oz copper, with minimum recommended pad on top layer and thermal vias to bottom layer ground plane.

Recommended Operating Conditions (Note 7) (@T

Symbol Parameter Min Max Unit

VIN

TA

Note: 7. The device function is not guaranteed outside of the recommended operating conditions.

AP6503A

Document number: DS36000 Rev. 2 - 2

Junction to Ambient 74 °C/W Junction to Case 16 °C/W

= +25°C, unless otherwise specified.)

A

Supply Voltage Operating Ambient Temperature Range

www.diodes.com

4.75

-40

3 of 15

23 V

+85 °C

P6503A

V V V

December 2012

A

Electrical Characteristics (V

Symbol Parameter Test Conditions Min Typ Max Unit

Shutdown Supply Current Supply Current (Quiescent) High-Side Switch On-Resistance (Note 8) — 100 — m Low-Side Switch On-Resistance (Note 8) — 100 — m HS Current Limit Minimum duty cycle — 5.5 — A LS Current Limit From Drain to Source — 0.9 — A

R

DS(ON)1

R

DS(ON)2

I

LIMIT

I

LIMIT

IIN IIN

High-Side Switch Leakage Current

AVEA

Error Amplifier Voltage Gain (Note 8)

GEA Error Amplifier Transconductance

COMP to Current Sense Transconductance

Oscillator Frequency Fold-back Frequency Maximum Duty Cycle Minimum On Time — 130 — ns Feedback Voltage

NEW PRODUCT

GCS

FSW

FFB

D

MAX

TON

VFB

Feedback Overvoltage Threshold — 1.1 — V

V

EN_Rising

EN Rising Threshold 0.7 0.8 0.9 V EN Lockout Threshold Voltage 2.2 2.5 2.7 V EN Lockout Hysteresis 220 mV

INUV INUV

V

VTH

VIN Under Voltage Threshold Hysteresis

HYS

Under Voltage Threshold Rising

IN

Soft-Start Current Soft-Start Period

TSD

Note: 8. Guaranteed by design

Thermal Shutdown (Note 8) — 160 — °C

AP6503A

Document number: DS36000 Rev. 2 - 2

= 12V, @TA = +25°C, unless otherwise specified.)

IN

VEN = 0V VEN = 2.0V, VFB = 1.0V

V

= 0V, VSW = 0V,

EN

=12V

V

SW

— 800 — V/V I

= ±10µA

C

— 2.8 — A/V V

= 0.75V

FB

V

= 0V

FB

VFB = 800mV

TA = -40°C to +85°C

3.80 4.05 4.40 V — 250 — mV V

= 0V

SS

= 0.1µF

C

SS

4 of 15

www.diodes.com

P6503A

— 0.3 3.0 µA — 0.6 1.5 mA

— 0 10 A

— 1000 — µA/V

210 240 260 kHz

— 0.30 — — 90 — %

900 925 950 mV

— 6 — A — 15 — ms

fSW

December 2012

A

C

O

G

Typical Performance Graphs (V

0.6

= 12V, V

IN

= 3.3V, TA = +25°C, unless otherwise specified.)

OUT

0.074

P6503A

NEW PRODUCT

0.58

0.56

0.54

0.52

0.5

QUIESCENT SUPPLY CURRENT (mA)

0.48 0 5 10 15 20 25

INPUT VOLTAGE (V )

Quiescent Supply Current vs. Input Voltage

6.2

6

5.8

5.6

5.4

0.064

0.054

0.044

0.034

0.024

0.014

SHUTDOWN SUPPLY CURRENT (µA)

0.004 0 5 10 15 20 25

3.33

3.329

3.328

3.327

3.326

3.325

3.324

Shutdown Supply Current vs. Input Voltage

INPUT VOLTAGE (V)

V = 12V

IN

5.2

5

4.8

-60 -40 -20 0 20 40 60 80 100 TEMPERATURE (C)

Current Limit vs. Temperature

0.92

0.918

0.916

0.914

E (V)

0.912

LTA

0.91

K V

0.908

0.906

FEEDBA

0.904

0.902

0.9

-60 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C)

Feedback Volt age vs. Temperature

AP6503A

Document number: DS36000 Rev. 2 - 2

5 of 15

www.diodes.com

3.323

OUTPUT VOLTAGE (V)

3.322

3.321

3.32

4.75 9.75 14.75 19.75 24.75 INPUT VOLTAGE (V)

Line Regu l at io n

255

250

245

240

235

OSCILLATOR FREQUENCY (Khz)

230

225

-60 -40 -20 0 20 40 60 TEMPERATURE (°C)

Oscillat or Fr equency vs. Temperature

100

80

December 2012