Diodes AP6502 User Manual

A

P6502

C

Y (%

Description

The AP6502 is a 340kHz switching frequency external compensated

synchronous DC/DC buck converter. It has integrated low R

high and low side MOSFETs.

The AP6502 enables continues load current of up to 2A with

DSON

Pin Assignments

SW

( Top View )

BS

1

2

IN

3

8

SS

EN

7

COMP

6

efficiency as high as 95%.

The AP6502 features current mode control operation, which enables

fast transient response times and easy loop stabilization.

4

SO-8EP

5

FB

GND

The AP6502 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.

NEW PRODUCT

The AP6502 is available in a standard Green SO-8 and SO-8EP

package with exposed PAD for improved thermal performance and is

RoHS compliant.

Features

• VIN 4.7V to 18V

• 2A Continuous Output Current, 3A Peak

• V

• 340kHz 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)

Adjustable from 0.925V to 16V

OUT

 OCP

 Thermal Shutdown

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

Figure 1 Package Pin Out

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.

Typical Application Circuit

340kHz 18V 2A SYNCHRONOUS DC/DC BUCK CONVERTER

100

90

V = 5V

IN

V = 12V

80

)

70

IEN

EFFI

60

50

V = 3.3V

OUT

L = 10µ H

40

0 0.4 0.8 1.2 1.6 2

LOAD CURRENT (A)

Effici ency vs. Load Current

AP6502

Document Number: DS35423 Rev. 9 - 2

IN

Figure 2 Typical Application Circuit

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Pin Descriptions

Number

Name

1 BS

2 IN

3 SW

4 GND Ground (Connect the exposed pad to Pin 4).

5 FB

NEW PRODUCT

6 COMP

7 EN

8 SS

EP EP EP exposed thermal pad connect to Pin 4 GND, not applicable in the SO-8 package.

Functional Block Diagram

P6502

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 4.7V to 18V 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 softstart period. A 0.1µF capacitor sets the soft-start period to 15ms. To disable the soft-start feature, leave SS floating.

5

FB

SS

8

COMP

6

EN

7

AP6502

Document Number: DS35423 Rev. 9 - 2

1.1V

0.3 V

0.925 V

0.9V

2.5V

+

-

+

-

+

-

+

-

ERROR

AMPLIFIER

LOCKOUT

COMPARATOR

OVP

OSCILLATOR

100/340 KHz

EN OK

SHUTDOWN

RAMP

E

CLK

+

-

6uA

Figure 3 Functional Block Diagram

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CURRENT

SENSE

AMPLIFIER

Logic

CURRENT

COMPARATOR

IN

INTERNAL

REGULATORS

+

-

100m

disable

IN < 4.10V

5V

IN

2

BS

1

SW

3

GND

4

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Absolute Maximum Ratings (Note 4) (@T

Symbol Parameter Rating Unit

VIN

VSW

VBS

VFB

VEN

V

COMP

TST

TJ

TL

NEW PRODUCT

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; 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.

Thermal Resistance (Note 6) (@T

Symbol Parameter Rating Unit

JA

JC

Note: 6. Test condition: SO-8: Device mounted on 1"x1" FR-4 substrate PCB, 2oz copper, with minimum recommended pad layout. 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.

Supply Voltage

Switch Node Voltage

Bootstrap Voltage

Feedback Voltage -0.3 to +6 V

Enable/UVLO Voltage -0.3 to +6 V

Comp Voltage -0.3 to +6 V

Storage Temperature -65 to +150 °C

Junction Temperature +150 °C

Lead Temperature +260 °C

= +25°C, unless otherwise specified.)

A

Junction to Ambient

Junction to Case

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.

AP6502

Document Number: DS35423 Rev. 9 - 2

Supply Voltage

Operating Ambient Temperature Range

= +25°C, unless otherwise specified.)

A

-0.3 to +20

-1.0 to V

V

SW

SO-8EP 74

SO-8 126

SO-8EP 16

SO-8 28

= +25°C, unless otherwise specified.)

A

4.7

-40

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+0.3

IN

-0.3 to VSW +6

18 V

+85 °C

P6502

V

°C/W

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Electrical Characteristics (V

Symbol Parameter Test Conditions Min Typ Max Unit

IIN

R

DS(ON)1

R

DS(ON)2

I

LIMIT

I

LIMIT

Shutdown Supply Current

Supply Current (Quiescent)

High-Side Switch On-Resistance (Note 8) 130 m

Low-Side Switch On-Resistance (Note 8) 130 m

HS Current Limit Minimum duty cycle 4.4 A

LS Current Limit From Drain to Source 0.9 A

High-Side Switch Leakage Current

AVEA Error Amplifier Voltage Gain

NEW PRODUCT

GEA

GCS

FSW

FFB

D

MAX

TON

VFB

(Note 8)

Error Amplifier Transconductance

COMP to Current Sense Transconductance

Oscillator Frequency

Fold-back Frequency

Maximum Duty Cycle

Minimum On Time 130 ns

Feedback Voltage

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

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

AP6502

Document Number: DS35423 Rev. 9 - 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

C

= 0.1µF

SS

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P6502

0.3 3.0 µA

0.6 1.5 mA

0 10 A

1000 µA/V

300 340 380 kHz

0.30

fSW

90 %

900 925 950 mV

6 A

15 ms

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C

OLT

G

Typical Performance Graphs (V

0.6

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

IN

0.074

P6502

NEW PRODUCT

0.58

0.56

0.54

0.52

0.5

QUIESCENT SUPPLY CURRENT (mA)

0.48 0 5 10 15 20

Quiescent Supply Current vs. Input Voltage

6.2

6

5.8

5.6

5.4

5.2

CURRENT LIMIT (A)

5

4.8

-60 -40 -20 0 20 40 60 80 100

0.92

0.918

0.916

E (V)

0.914

A

0.912

INPUT VOLTAGE (V)

TEMPERATURE (C)

Current Limit vs. Temperature

0.064

0.054

0.044

0.034

0.024

0.014

SHUTDOWN SUPPLY CURRENT (µA)

0.004 0 5 10 15 20

OUTPUT VOLTAGE (V)

Shutdown Supply Current vs. Input Voltage

3.33

3.329

3.328

3.327

3.326

3.325

3.324

3.323

3.322

3.321

3.32 4101520

375

370

365

INPUT VOLTAGE (V)

V = 12V

IN

INPUT VOLTAGE (V)

Line Regulation

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 Voltage vs. Temperature

AP6502

Document Number: DS35423 Rev. 9 - 2

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360

355

OSCILLATOR FREQUENCY (Khz)

350

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

Oscillator Frequency vs. Temperature

January 2013