Richtek RT8061AZQW Schematic [ru]

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RT8061A

3A, 1MHz, Synchronous Step-Down Converter

General Description

The RT8061A is a high efficiency synchronous, step-down DC/DC converter. Its input voltage range from 2.7V to 5.5V that provides an adjustable regulated output voltage from 0.6V to VIN while delivering up to 3A of output current. The internal synchronous low on resistance power switches increase efficiency and eliminate the need for an external Schottky diode. The switching frequency is fixed internally at 1MHz. The 100% duty cycle provides low dropout operation, hence extending battery life in portable systems. Current mode operation with internal compensation allows the transient response to be optimized over a wide range of loads and output capacitors. The RT8061A is operated in PWM/PSM mode to achieve high efficiency for a wide load range. The RT8061A is available in a WDFN-10L 3x3 package.

Ordering Information

RT8061A

Package Type

QW : WDFN-10L 3x3 (W-Type)

Lead Plating System

Z : ECO (Ecological Element with Halogen Free and Pb free)

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.

Features

zHigh Efficiency : Up to 95%

zLow RDS(ON) Internal Switches : 69mΩ/49mΩ at VIN = 5V

zFixed Frequency : 1MHz

zNo Schottky Diode Required

z0.6V Reference Allows Low Output Voltage

zPWM/PSM Mode Operation

zLow Dropout Operation : 100% Duty Cycle

zOCP, UVP, OVP, OTP

zRoHS Compliant and Halogen Free

Applications

zPortable Instruments

zBattery-Powered Equipment

zNotebook Computers

zDistributed Power Systems

zIP Phones

zDigital Cameras

Pin Configurations

(TOP VIEW)

NC 1

 

10

PVIN

LX 2

GND

9

PVIN

LX 3

8

SVIN

 

PGOOD 4

 

7

NC

EN 5

11 6

FB

WDFN-10L 3x3

Marking Information

 

11 : Product Code

11 YM

YMDNN : Date Code

DNN

 

 

 

Copyright ©2012 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

DS8061A-04 September 2012

www.richtek.com

 

1

Richtek RT8061AZQW Schematic

RT8061A

 

 

 

 

Typical Application Circuit

 

 

 

 

RT8061A

LOUT

 

 

4 PGOOD

 

 

PGOOD

 

LX 2, 3

VOUT

R1

 

 

RFB1

COUT

VIN

9, 10 PVIN

 

CFF

 

FB 6

 

CIN

8 SVIN

 

 

 

 

 

RFB2

 

 

C1

 

 

 

 

 

 

Chip Enable

5 EN

GND 11 (Exposed Pad)

 

 

 

Functional Pin Description

Pin No.

Pin Name

Pin Function

1, 7

NC

No Internal Connection.

 

 

 

2, 3

LX

Switch Node. Connection this pin to the inductor.

 

 

 

4

PGOOD

Power Good Indicator. This pin is an open drain logic output that is pulled to

ground when the output voltage is less than 90% of the target output voltage.

 

 

5

EN

Enable Control. Pull high to turn on. Do not float.

6

FB

Feedback. This pin receives the feedback voltage from a resistive voltage divider

connected across the output.

 

 

8

SVIN

Signal Input. Decouple this pin to GND with at least 1μF ceramic cap.

9, 10

PVIN

Power Input. Decouple this pin to GND with at least 4.7μF ceramic cap.

11 (Exposed Pad)

GND

The exposed pad must be soldered to a large PCB and connected to GND for

maximum power dissipation.

 

 

Function Block Diagram

 

 

 

 

 

 

 

 

EN

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PVIN

 

 

 

 

 

EN

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ISEN

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

OSC

 

 

Slope

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PGOOD

 

PGOOD

 

 

 

 

 

 

 

 

Com

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0.6V

 

EN

Output

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

OC

 

 

 

 

 

 

 

 

 

FB

 

 

 

 

Clamp

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Limit

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Int-SS

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Driver

 

 

 

 

LX

 

 

 

0.72V

 

 

OV

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Control

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0.54V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Logic

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PGOOD

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NISEN

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0.4V

 

 

UV

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Zero Current

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

POR

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SVIN

 

 

 

 

 

 

 

 

 

 

 

VREF

 

 

 

OTP

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Copyright ©2012 Richtek Technology Corporation. All rights reserved.

 

 

 

 

 

 

 

 

 

 

 

 

 

is a registered trademark of Richtek Technology Corporation.

www.richtek.com

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DS8061A-04 September 2012

2

 

 

 

 

 

 

 

RT8061A

Absolute Maximum Ratings (Note 1)

 

 

 

 

 

 

z Supply Input Voltage, PVIN, SVIN--------------------------------------------------------------------------------

 

 

 

−0.3V to 6.5V

z LX Pin Voltage---------------------------------------------------------------------------------------------------------

 

 

 

 

 

(VIN + 0.3V) to 6.8V

z Other I/O Pin Voltage ------------------------------------------------------------------------------------------------

 

 

 

 

−0.3V to 6.5V

z Power Dissipation, PD @ TA = 25°C

 

 

 

 

 

 

 

WDNF-10L 3x3 --------------------------------------------------------------------------------------------------------

 

 

 

 

 

1.429W

 

z Package Thermal Resistance (Note 2)

 

 

 

 

 

 

 

WDFN-10L 3x3, θJA

--------------------------------------------------------------------------------------------------

 

 

 

 

70°C/W

 

WDFN-10L 3x3 θJC --------------------------------------------------------------------------------------------------

 

 

 

 

8.2°C/W

 

z Junction Temperature ------------------------------------------------------------------------------------------------

 

 

 

 

150°C

 

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

 

 

 

260°C

 

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

 

 

 

 

−65°C to 150°C

z ESD Susceptibility

(Note 3)

 

 

 

 

 

 

 

 

HBM (Human Body Model) -----------------------------------------------------------------------------------------

 

 

 

 

2kV

 

 

 

Recommended Operating Conditions

(Note 4)

 

 

 

 

 

z Supply Input Voltage, PVIN, SVIN--------------------------------------------------------------------------------

 

 

 

2.7V to 5.5V

 

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

 

 

 

 

−40°C to 125°C

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

 

 

 

 

−40°C to 85°C

Electrical Characteristics

 

 

 

 

 

 

 

(VIN = 3.3V, TA = 25°C, unless otherwise specified)

 

 

 

 

 

 

 

Parameter

Symbol

Test Conditions

Min

Typ

Max

 

Unit

Feedback Reference Voltage

VREF

 

 

0.594

0.6

0.606

 

V

Feedback Leakage Current

IFB

 

 

--

0.1

0.4

 

μA

DC Bias Current

 

 

Active , VFB = 0.7V, Not Switching

--

110

140

 

μA

 

 

Shutdown

 

--

--

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Output Voltage Line Regulation

 

VIN = 2.7V to 5.5V IOUT = 0A

--

0.3

--

 

%/V

Output Voltage Load Regulation

 

IOUT = 0A to 3A

−1

--

1

 

%

Switch Leakage Current

 

VEN = 0A

 

--

--

1

 

μA

Switching Frequency

 

 

 

0.8

1

1.2

 

MHz

 

 

 

 

 

 

 

 

 

 

Switch On Resistance, High

RDS(ON)_P

VIN = 5V

 

--

69

--

 

Switch On Resistance, Low

RDS(ON)_N

VIN = 5V

 

--

49

--

 

PMOS Current Limit (latch-off)

ILIM

 

 

4

--

--

 

A

Under Voltage Lockout

VUVLO

VIN Rising

 

2.2

2.4

2.6

 

V

Threshold

 

VIN Falling

 

2

2.2

2.4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EN Threshold

 

Logic-High

VIH

 

 

1.6

--

--

 

V

Voltage

 

Logic-Low

VIL

 

 

--

--

0.4

 

 

 

 

 

 

 

 

 

 

 

 

EN Pull Low Resistance

 

 

 

--

500

--

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Copyright ©2012 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

 

DS8061A-04 September 2012

 

 

 

 

 

www.richtek.com

3

RT8061A

Parameter

Symbol

Test Conditions

Min

Typ

Max

Unit

 

 

 

 

 

 

 

Over Temperature

TSD

 

--

150

--

°C

Protection (latch-off)

 

 

 

 

 

 

 

Soft-Start Time

tSS

 

500

--

--

μs

VOUT Discharge Resistance

 

 

--

100

--

Ω

 

 

 

 

 

 

 

VOUT Over Voltage

 

 

 

 

 

 

Protection (latch-off, delay

 

 

115

120

130

%

time = 10μs)

 

 

 

 

 

 

VOUT Under Voltage

 

 

57

66

75

%

Lockout Threshold

 

 

(latch-off)

 

 

 

 

 

 

Power Good

 

Measured FB, With Respect to VREF

85

90

--

%

 

 

 

 

 

 

 

Power Good Hysteresis

 

 

--

5

--

%

 

 

 

 

 

 

 

Note 1. Stresses beyond those listed “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 in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may affect device reliability.

Note 2. θJA is measured at TA = 25°C on a high effective thermal conductivity four-layer test board per JEDEC 51-7. θJC is measured at the exposed pad of the package.

Note 3. Devices are ESD sensitive. Handling precaution is recommended.

Note 4. The device is not guaranteed to function outside its operating conditions.

Copyright ©2012 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

www.richtek.com

DS8061A-04 September 2012

4

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