Richtek RT8020AGQW, RT8020APQW, RT8020BGQW, RT8020BPQW, RT8020CGQW, RT8020CPQW, RT8020DPQW, RT8020GQW, RT8020PQW Schematic [ru]

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RT8020

Dual High-Efficiency PWM Step-Down DC/DC Converter

General Description

The RT8020 is a dual high-efficiency Pulse-Width- Modulated (PWM) step-down DC/DC converter. It is capable of delivering 1A output current over a wide input voltage range from 2.5V to 5.5V, the RT8020 is ideally suited for portable electronic devices that are powered from 1-cell Li-ion battery or from other power sources within the range such as cellular phones, PDAs and other handheld devices.

Two operational modes are available : PWM/Low-Dropout auto-switch and shutdown modes. Internal synchronous rectifier with low RDS(ON) dramatically reduces conduction loss at PWM mode. No external Schottky diode is required in practical application.

The RT8020 enters Low-Dropout mode when normal PWM cannot provide regulated output voltage by continuously turning on the upper PMOS. The RT8020 enter shutdown mode and consumes less than 0.1μAwhen ENpin is pulled low.

The switching ripple is easily smoothed-out by small package filtering elements due to a fixed operation frequency of 1.5MHz. This along with small WDFN-12L 3x3 package provides small PCB area application. Other features include soft start, lower internal reference voltage with 2% accuracy, over temperature protection, and over current protection.

Pin Configurations

(TOP VIEW)

VIN2

1

 

12

EN2

LX2

2

 

11

NC2

GND 3

GND

10

FB2

FB1 4

9

GND

 

NC1

5

 

8

LX1

EN1

6

13 7

VIN1

WDFN-12L 3x3

Features

2.5V to 5.5V Input Range Adjustable Output From 0.6V to VIN

1.2V, 1.3V, 1.8V, 2.5V and 3.3V Fixed/ Adjustable Output Voltage

1A Output Current

95% Efficiency

No Schottky Diode Required

50uA Quiescent Current per Channel 1.5MHz Fixed Frequency PWM Operation Small 12-Lead WDFN Package

RoHS Compliant and 100% Lead (Pb)-Free

Applications

Mobile Phones

Personal Information Appliances

Wireless and DSL Modems

MP3 Players

Portable Instruments

Ordering Information

RT8020

Package Type

QW : WDFN-12L 3x3 (W-Type)

Lead Plating System

P : Pb Free

G : Green (Halogen Free and Pb Free)

Output Voltage : VOUT1/VOUT2

Default : Adjustable

A : 3.3V/1.8V

B : 3.3V/1.3V

C : 3.3V/1.2V

D : 2.5V/1.8V

Note :

Richtek products are :

`RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.

`Suitable for use in SnPb or Pb-free soldering processes.

Copyright ©2012 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

DS8020-06 March 2012

www.richtek.com

 

1

RT8020

Marking Information

RT8020APQW

 

RT8020CPQW

 

 

 

C2- : Product Code

 

 

 

C4- : Product Code

 

 

 

 

 

C2-YM

 

YMDNN : Date Code

 

C4-YM

 

YMDNN : Date Code

DNN

 

 

 

DNN

 

 

 

 

 

 

 

 

 

RT8020AGQW

 

RT8020CGQW

 

 

 

C2= : Product Code

 

 

 

C4= : Product Code

 

 

 

 

 

C2=YM

 

YMDNN : Date Code

 

C4=YM

 

YMDNN : Date Code

DNN

 

 

 

DNN

 

 

 

 

 

 

 

 

 

RT8020BPQW

 

RT8020DPQW

 

 

 

C3- : Product Code

 

 

 

C5- : Product Code

 

 

 

 

 

C3-YM

 

YMDNN : Date Code

 

C5-YM

 

YMDNN : Date Code

DNN

 

 

 

DNN

 

 

 

 

 

 

 

 

 

RT8020BGQW

 

RT8020DGQW

 

 

 

C3= : Product Code

 

 

 

C5=: Product Code

C3=YM

 

YMDNN : Date Code

 

C5=YM

 

YMDNN : Date Code

DNN

 

 

 

DNN

 

 

 

 

 

 

 

 

 

Typical Application Circuit

 

VIN2

 

 

 

 

 

1

 

CIN2

 

2

 

4.7µF

3, Exposed Pad (13)

 

 

 

R12

 

4

 

 

 

5

 

C11

R11

6

 

22pF

850k

 

 

VOUT1

 

 

 

= VREF ×(1+ Rx1)

COUT1

 

VOUTx

4.7µF

 

 

 

 

Rx2

 

 

L2

 

 

COUT2

 

 

 

4.7µF

 

2.2µH

 

 

 

VOUT2

 

 

 

 

RT8020

 

 

 

 

VIN2

EN2

12

R21

C21

 

 

11

850k

22pF

LX2

NC2

 

 

GND

FB2

10

 

 

FB1

GND

9

 

R22

 

 

8

CIN1

NC1

LX1

 

EN1

VIN1

7

4.7µF

VIN1

 

L1

 

 

 

 

2.2µH

 

 

 

 

Figure 1. Adjustable Voltage Regulator

Copyright ©2012 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

www.richtek.com

DS8020-06 March 2012

2

 

RT8020

L2

2.2µH

 

VIN2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VOUT2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RT8020

 

 

 

 

 

 

 

 

 

 

 

 

 

COUT2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

VIN2

EN2

12

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CIN2

 

 

2

11

 

 

 

 

 

 

 

 

 

 

 

 

4.7µF

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

LX2

NC2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4.7µF

 

 

 

10

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3, Exposed Pad (13)

GND

FB2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

9

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

FB1

GND

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

5

 

 

8

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NC1

LX1

 

 

 

CIN1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6

 

 

7

 

 

 

4.7µF

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EN1

VIN1

 

 

 

 

 

 

 

 

 

VIN1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

L1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VOUT1

 

 

 

 

 

 

 

 

2.2µH

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

COUT1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4.7µF

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VOUTx = 1.2V, 1.3V, 1.8V, 2.5V or 3.3V

 

Figure 2. Fixed Voltage Regulator

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Functional Pin Description

Pin No.

Pin Name

Pin Function

1

VIN2

Power Input of Channel 2.

 

2

LX2

Pin for Switching of Channel 2.

 

3, 9,

GND

Ground. The exposed pad must be soldered to a large PCB and connected to

Exposed Pad (13)

GND for maximum power dissipation.

 

4

FB1

Feedback of Channel 1.

 

5, 11

NC1, NC2

No Connection or Connect to VIN.

 

6

EN1

Chip Enable of Channel 1 (Active High). VEN1

VIN1.

7

VIN1

Power Input of Channel 1.

 

8

LX1

Pin for Switching of Channel 1.

 

10

FB2

Feedback of Channel 2.

 

12

EN2

Chip Enable of Channel 2 (Active High). VEN2

VIN2.

Copyright ©2012 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

DS8020-06 March 2012

www.richtek.com

 

3

Richtek RT8020AGQW, RT8020APQW, RT8020BGQW, RT8020BPQW, RT8020CGQW, RT8020CPQW, RT8020DPQW, RT8020GQW, RT8020PQW Schematic

RT8020

Function Block Diagram

 

 

ENx

 

 

VINx

 

OSC and

 

 

RS1

 

Current Limit

 

 

 

Shutdown

 

 

 

Detector

 

 

 

 

Control

 

 

Slope

 

 

 

 

 

 

 

 

 

Compensation

 

 

 

 

 

 

 

Current

 

 

 

 

 

Sense

 

 

 

 

 

PWM

 

 

 

 

Comparator

Control

 

 

 

 

 

Driver

LXx

 

 

 

Logic

 

 

 

 

 

Error

 

 

 

 

 

Amplifier

 

 

 

 

 

FBx

 

 

 

 

 

 

RC

UVLO and

 

 

 

 

Power Good

 

 

 

 

 

 

 

 

COMP

 

Detector

 

 

RS2

 

 

 

 

 

 

VREF

 

GND

 

 

 

 

Copyright ©2012 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

www.richtek.com

DS8020-06 March 2012

4

 

RT8020

Absolute Maximum Ratings (Note 1)

 

Supply Input Voltage, VIN1, VIN2 ----------------------------------------------------------------------------------

−0.3V to 6.5V

EN1, FB1, LX1, EN2, FB2 and LX2 Pin Voltage --------------------------------------------------------------

−0.3V to (VIN + 0.3V)

Power Dissipation, PD @ TA = 25°C

 

WDFN-12L 3x3 --------------------------------------------------------------------------------------------------------

1.667W

Package Thermal Resistance (Note 2)

 

WDFN-12L 3x3, θJA --------------------------------------------------------------------------------------------------

60°C/W

WDFN-12L 3x3, θJC --------------------------------------------------------------------------------------------------

8.2°C/W

Lead Temperature (Soldering, 10 sec.) --------------------------------------------------------------------------

260°C

Junction Temperature ------------------------------------------------------------------------------------------------

150°C

Storage Temperature Range ---------------------------------------------------------------------------------------

−65°C to 150°C

ESD Susceptibility (Note 3)

 

HBM (Human Body Mode) -----------------------------------------------------------------------------------------

2kV

MM (Machine Mode) -------------------------------------------------------------------------------------------------

200V

Recommended Operating Conditions

(Note 4)

Supply Input Voltage -------------------------------------------------------------------------------------------------

2.5V to 5.5V

Junction Temperature Range ---------------------------------------------------------------------------------------

−40°C to 125°C

Ambient Temperature Range ---------------------------------------------------------------------------------------

−40°C to 85°C

Electrical Characteristics

(VIN = 3.6V, VOUT = 2.5V, VREF = 0.6V, L = 2.2uH, CIN = 4.7μF, COUT = 10μF, TA = 25°C, IMAX= 1A unless otherwise specified)

Parameter

Symbol

Test Conditions

 

Min

Typ

Max

Unit

 

 

 

 

 

 

 

 

 

 

 

 

Channel 1 and Channel 2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Input Voltage Range

VIN

 

 

 

2.5

--

5.5

V

 

Under Voltage Lock Out

UVLO

 

 

 

--

1.8

--

V

 

threshold

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Hysteresis

 

 

 

 

 

--

0.1

--

V

 

 

 

 

 

 

 

 

 

 

Quiescent Current

IQ

IOUT = 0mA, VFB = VREF + 5%

--

50

70

μA

 

Shutdown Current

ISHDN

EN = GND

 

 

--

0.1

1

μA

 

Reference Voltage

VREF

For Adjustable Output Voltage

0.588

0.6

0.612

V

 

Adjustable Output Voltage

VOUT

(Note 6)

 

 

VREF

--

VIN − V

V

 

Range

 

 

 

 

 

 

 

VOUT

VIN = 2.5V to 5.5V, VOUT = 1.2V

−3

--

3

%

 

 

 

 

0A < IOUT < 1A

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VOUT

VIN = 2.5V to 5.5V, VOUT = 1.3V

−3

--

3

%

 

 

 

 

0A < IOUT < 1A

 

 

 

 

 

 

 

 

 

 

 

 

Output Voltage

 

Fix

VOUT

VIN = 2.5 to 5.5V, VOUT = 1.8V

−3

--

3

%

 

Accuracy

 

 

 

0A < IOUT < 1A

 

 

 

 

 

 

 

 

 

VOUT

VIN = VOUT +

V to 5.5V

(Note 5)

--

3

%

 

 

 

 

VOUT = 2.5V, 0A < IOUT < 1A

3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VOUT

VIN = VOUT +

V to 5.5V

(Note 5)

−3

--

3

%

 

 

 

 

VOUT = 3.3V, 0A < IOUT < 1A

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Copyright ©2012 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

DS8020-06 March

2012

 

 

 

 

 

 

www.richtek.com

 

 

 

 

 

 

 

 

 

 

5

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