Diodes AP3595 User Manual

AP3595

Document number: DS36749 Rev. 1 - 2

1 of 23

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January 2014

AP3595

A Product Line of

Diodes Incorporated

Description

The AP3595 is a compact dual phase synchronous rectified buck controller specifically designed to deliver high quality output voltage. This device operates at adjustable operation frequency and is capable of delivering up to 60A output current.

This controller integrates internal MOSFET drivers that support 12V+12V bootstrapped voltage for high efficiency power conversion. The bootstrap diode is built-in to simplify the circuit design and minimize external part count.

The AP3595 features configurable gate driving voltage for maximum efficiency and optimal performance. The built-in bootstrap diode simplifies the circuit design and reduces external part count and PCB space. The output voltage is precisely regulated to the reference input that is dynamically adjustable by external voltage divider.

Other features include adjustable soft start, adjustable operation frequency, and quick response to step-load transient. With aforementioned functions, the IC provides customers a compact, high efficiency, well-protected and cost-effective solution.

This IC is available in U-QFN4040-24 package.

Features

 Operate with Single Supply Voltage  Simple Single Loop Voltage Mode Control  12V+12V Bootstrapped Drivers with Internal Bootstrap Diode  Adjustable Over Current Protection by DCR  Current Sensing  Adjustable Current Balancing by R

DS(ON)

Current Sensing

 Adjustable Operation Frequency from 50kHz to 1MHz Per Phase  External Compensation  Dynamic Output Voltage Adjustment  Adjustable Soft Start  U-QFN4040-24 Package  RoHS Compliant and 100% Lead (Pb)-free  Totally Lead-free & Fully RoHS Compliant (Note1 & 2)  Halogen and Antimony Free. “Green” Device (Note 3)

Pin Assignments

(Top View)

LG2

PHASE2

HG2

BOOT2

VID

RSET

PSI

CSP

CSN

EAP

FBRTN

COMP

IOFS

RT/EN

VREF

REFIN

VCC PVCC

LG1

PHASE1 HG1

BOOT1

Pin 1 Mark

7 8 9 11 12

192021222324

U-QFN4040-24 (FN Package)

Applications

 Middle-High End GPU Core Power  High End Desktop PC Memory Core Power  Low Output Voltage, High Power Density  DC-DC Converters  Voltage Regulator Modules

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/quality/lead_free.html 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.

DUAL PHASE SYNCHRONOUS RECTIFIED BUCK CONTROLLER

AP3595

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January 2014

AP3595

A Product Line of

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AP3595

BOOT1

HG1

PHASE1

LG1

VCC

OUT

BOOT2

HG2

PHASE2

LG2

FBRTN

COMP

RT/EN

GND

VID

EAP

RSET

REFIN

VREF

IOFS

PSI

PVCC

CSP

FBRTN

CSN

PHASE2 PHASE1

OUT

17 11

10 12

Typical Applications Circuit

AP3595

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AP3595

A Product Line of

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Pin Number

Pin Name

Function

REFIN

External Reference Input. This is the input pin of external reference voltage. Connect a voltage divider from VREF to REFIN and FBRTN to set the reference voltage

VREF

Output for Reference Voltage. This is the output pin of high precision 2V reference voltage. Bypass this pin with a 1F ceramic capacitor to FBRTN

RT/EN

Operation Frequency Setting. Connecting a resistor between this pin and GND to set the operation frequency. Pull this pin to ground to shut down the AP3595

IOFS

Current Balance Adjustment. Connect a resistor from this pin to VREF or GND to adjust the current sharing

COMP

Error Amplifier Output. This is the output of the error amplifier (EA) and the non-inverting input of the PWM comparators. Use this pin in combination with the FB pin to compensate the voltage control feedback loop of the converter

Feedback Voltage. This pin is the inverting input to the error amplifier. Use this pin in combination with the COMP pin to compensate the voltage control feedback loop of the converter

FBRTN

Feedback Return. Connect this pin to the ground where the output voltage is to be regulated

EAP

Non-inverting Input of Error Amplifier. Connect a resistor from this pin to SS pin to set the droop slope

Soft Start Output. Connect a capacitor to FBRTN to set the soft start interval

CSN

Negative Input for Current Sensing Amplifier

CSP

Positive Input for Current Sensing Amplifier

PSI

Power Saving Mode. Connect this pin to VREF for always two phase operation. Short this pin to ground for always single phase operation

BOOT1

Bootstrap Supply for the Floating Upper Gate Driver of Channel 1. Connect a bootstrap capacitor between BOOT1 pin and the PHASE1 pin to form a bootstrap circuit

HG1

Upper Gate Driver Output for Channel 1. Connect this pin to the gate of upper MOSFET. This pin is monitored by the adaptive shoot-through protection circuitry to determine when the upper MOSFET has turned off

PHASE1

Switch Node for Channel 1. Connect this pin to the source of the upper MOSFET and the drain of the lower MOSFET. This pin is used as the sink for the Upper GATE driver. It is also monitored by the adaptive shoot-through protection circuitry to determine when the upper MOSFET has turned off

LG1

Lower Gate Driver Output for Channel 1. Connect this pin to the gate of lower MOSFET. This pin is monitored by the adaptive shoot-through protection circuitry to determine when the lower MOSFET has turned off

PVCC

Supply Voltage for Gate Driver. This pin is the output of internal 9V LDO. This pin provides current for gate drivers. Bypass this pin with a minimum 1F ceramic capacitor

VCC

Supply Voltage. This pin provides current for internal control circuit and 9V LDO. Bypass this pin with a minimum 1F ceramic capacitor next to the IC

LG2

Lower Gate Driver Output for Channel 2. Connect this pin to the gate of lower MOSFET. This pin is monitored by the adaptive shoot-through protection circuitry to determine when the lower MOSFET has turned off

PHASE2

Switch Node for Channel 2. Connect this pin to the source of the upper MOSFET and the drain of the lower MOSFET. This pin is used as the sink for the HG2 driver. It is also monitored by the adaptive shoot-through protection circuitry to determine when the upper MOSFET has turned off

HG2

Upper Gate Driver Output for Channel 2. Connect this pin to the gate of upper MOSFET. This pin is monitored by the adaptive shoot-through protection circuitry to determine when the upper MOSFET has turned off

BOOT2

Bootstrap Supply for the Floating Upper Gate Driver of Channel 2. Connect a bootstrap capacitor between BOOT2 pin and the PHASE2 pin to form a bootstrap circuit

VID

VID Input. This pin is used to adjust the reference voltage. Logic high enables the internal MOSFET connected to RSET pin

RSET

Reference Voltage Setting. This pin is an open drain output that is pulled low when VID sets to high. Connect a resistor from this pin to REFIN pin to set the reference voltage

Exposed Pad

GND

Power Ground. Tie this pin to the ground island/plane through the lowest available impedance connection

Pin Descriptions

AP3595

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AP3595

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Reference

Voltage

POR

Internal

Regulator

Gate

Control

Logic

DUAL PHASE

Control

Gate

Control

Logic

OCP OVP UVP

Power Saving

Setting

Oscillator

BOOT1

HG1

PHASE1

LG1

BOOT2

HG2

LG2

PVCC

PWM

Current

Balance

RT/EN

PHASE1 PHASE2

IOFS

VREF

RSET

VID

FBRTN

REFIN

EAP

Error

Amplifier

COMP

CSN CSP

PSI

VCC

1 9

8 6

PHASE2

Symbol

Parameter

Rating

Unit

VCC

Supply Input Voltage

-0.3 to 15

PHASE

PHASE to GND Voltage

-0.3 to 15

<200ns

-5 to 30

VHG

HG to PHASE Voltage

-0.3 to V

BOOT-PHASE

+0.3

<200ns

-5 to V

BOOT-PHASE

VLG

LG to GND Voltage

-0.3 to VCC+0.3

<200ns

-5 to VCC+5

–

BOOT to PHASE Voltage

BOOT

BOOT to GND Voltage

-0.3 to V

PHASE

+15

<200ns

-0.3 to 42

Input, Output or I/O Voltage

-0.3 to 6

Power Dissipation

2.5



Thermal Resistance (Junction to Ambient)

°C/W

STG

Storage Temperature Range

-65 to +150

ºC

Junction Temperature

+150

ºC

LEAD

Lead Temperature (Soldering, 10sec)

+260

ºC

HBM

ESD (Human Body Model)

2000

ESD (Machine Model)

200

Functional Block Diagram

Absolute Maximum Ratings(Note 4)

Note 4: Stresses greater than those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and

functional operation of the device at these or any other conditions beyond those indicated under “Recommended Operating Conditions” is not implied. Exposure to “Absolute Maximum Ratings” for extended periods may affect device reliability.

AP3595

Document number: DS36749 Rev. 1 - 2

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AP3595

A Product Line of

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Symbol

Parameter

Min

Max

Unit

VCC

Supply Input Voltage

10.8

13.2

Operating Ambient Temperature

-40

+85

°C

Operating Junction Temperature

-40

+125

°C

Symbol

Parameter

Conditions

Min

Typ

Max

Unit

SUPPLY INPUT

VCC

Supply Input Voltage

–

10.8

–

13.2

ICC

Supply Current

HG and LG Open, VCC=12V, Switching

– 5 –

Quiescent Current

No Switching, I

PCC

=0mA

– 4 –

PCC

Regulated Supply Voltage

RT/EN=0V, I

PCC

=0mA

8 9 10

RTH

POR Threshold

–

8 9 10

HYS

POR Hysteresis

–

– 1 –

CHIP ENABLE/FREQUENCY SETTING

RT/EN

RT/EN Sourcing Current

RT/EN

=GND

100

150

200

A

RT/EN

RT/EN Voltage

RRT=33kΩ

– 1 – V –

Switching Frequency Setting Range

–

50 – 1000

kHz

OSC

Free Run Switching Frequency

RRT=33kΩ

270

300

330

kHz

△f

OSC

Switching Frequency Accuracy

OSC

=200kHz to 500kHz

-15 – 15

OSCILLATOR

–

Maximum Duty Cycle

–

40 – %

–

Minimum Duty Cycle

–

– 0 –

OSC

Ramp Amplitude

VCC=12V

–

3.5 – V

POWER SAVING MODE

PSI_H

Threshold Voltage for Entering Dual Phase

PSI

rising

1.2 – –

PSI_L

Threshold Voltage for Entering Single Phase

PSI

falling

– – 0.4

REFERENCE VOLTAGE

REF

Reference Voltage Accuracy

REF

=100A

1.98

2.0

2.02

△V

REF

Reference Voltage Load Regulation

REF

=0 to 2mA

-5 – 5

△V

Output Voltage Accuracy

REFIN-VFB

|, VCC=12V, No Load,

DRP

=0, V

REFIN

=0.8V to 1.6V

– – 5

ERROR AMPLIFIER

Open Loop DC Gain

Guaranteed by design

80 – dB

GBW

Gain Bandwidth Product

LOAD

=5pF, Guaranteed by design

–

20 – MHz

Slew Rate

Guaranteed by design

–

V/s

COMP

Maximum Current (Sink and Source)

COMP

=1.6V

1.5

2.0 – mA

Recommended Operating Conditions

Electrical Characteristics (@V

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

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AP3595

A Product Line of

Diodes Incorporated

Symbol

Parameter

Conditions

Min

Typ

Max

Unit

SOFT START

ISS

Soft Start Current

During soft start

–

A

SS_CC

Supply Current

After soft start end

–

200

–

A

TOTAL CURRENT SENSE

CSN_MAX

Maximum Sourcing Current

–

100 – –

A

–

GM Amplifier Offset Voltage

–

-5 0 5

CSN_OCP

Over Current Protection Threshold

–

A

DRP/ICSN

Droop Accuracy

–

100

110

PSI/ICSN

PSI Accuracy

–

100

110

PHASE CURRENT SENSE

–

Trans-conductance

–

1.0 – mS

OFS

IOFS Voltage 100kfrom IOFS to VREF

–

1.5

–

100kfrom IOFS to GND

–

0.5

–

VID CONTROL INPUT

VIH

Logic High Threshold Level

–

1.2 – –

VIL

Logic Low Threshold Level

–

– – 0.4

RSET

On Resistance of RSET MOSFET

VID=High

–



RSET

Leakage Current of RSET Pin

RSET

=2V, VID=0V

– – 0.1

A

GATE DRIVER

HG_SRC

Upper Gate Sourcing Current

BOOT-VPHASE

=6V

–

1.2 – A

HG_SNK

Upper Gate Sinking Resistance

IHG=100mA sinking

–

1.5



LG_SRC

Lower Gate Sourcing Current

PCC-VLG

=6V

–

1.2 – A

LG_SNK

Lower Gate Sinking Resistance

ILG=100mA sinking

– 1 2



tDT

Dead Time

–

50 – ns

PROTECTION

VFB-VSS

Over Voltage Protection

–

300 – mV

VFB-VSS

Under Voltage Protection

–

-300

–

Over Temperature Protection

–

+150

–

°C

–

Over Temperature Hysteresis

–

+20 – °C

Electrical Characteristics (Cont.) (@V

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

AP3595

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AP3595

A Product Line of

Diodes Incorporated

4 6 8 10 12 14

1.980

1.982

1.984

1.986

1.988

1.990

1.992

1.994

1.996

1.998

2.000

REF

(V)

VCC (V)

LOAD

=0mA

LOAD

=2mA

0 5 10 15 20

1.980

1.982

1.984

1.986

1.988

1.990

1.992

1.994

1.996

1.998

2.000

REF

(V)

LOAD

(mA)

0 20 40 60 80 100

8.85

8.90

8.95

9.00

9.05

9.10

PCC

(V)

LOAD

(mA)

4 6 8 10 12 14

PCC

(V)

VIN (V)

LOAD

=0mA

LOAD

=10mA

9 10 11 12 13 14

4.6

4.8

5.0

5.2

5.4

5.6

5.8

6.0

6.2

6.4

(mA)

VIN (V)

9 10 11 12 13 14

290

292

294

296

298

300

302

304

306

308

310

OSC

(kHz)

VIN (V)

Performance Characteristics

Line Regulation V

REF

Load Regulation V

PCC

ICC vs.V

Load Regulation

REF

Line Regulation

PCC

vs.V

OSC

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