Richtek RT8058GQW, RT8058PQW Schematic [ru]

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RT8058

1MHz, 2A, High Efficiency PWM Step-Down DC/DC Converter

General Description

The RT8058 is a current mode PWM step-down converter. The chip is ideal for fixed frequency and low ripple applications over full range of load conditions. Its input voltage range is from 2.6V to 5.5V with a constant 1MHz switching frequency that allows it to adopt tiny, low cost capacitors and inductors with 2mm or less in height making it ideal for single-cell Li-lon/polymer battery applications. The low on resistance internal MOSFET can achieve high efficiency without the need of external schottky diodes in wide operating ranges and the output voltage is adjustable from 0.6V to 5V that can provide up to 2A load current. The RT8058 operates at 100% duty cycle for low dropout operation that extends battery life in portable devices.

The RT8058 is available in a WQFN-16L 3x3 package.

Features

z0.6V Reference Allows Low Output Voltage

zLow Dropout Operation : 100% Duty Cycle

z2A Load Current

z<2μA Shutdown Current

zUp to 95% Efficiency

zNo Schottky Diode Required

z1MHZ Constant Switching Frequency

zLow RDS(ON) Internal Switches

zInternally Compensated

zInternal Soft-Start

zOver temperature Protection

zShort Circuit Protection

zSmall 16-Lead WQFN Package

zRoHS Compliant and 100% Lead (Pb)-Free

Ordering Information

RT8058

Package Type

QW : WQFN-16L 3x3 (W-Type)

Lead Plating System P : Pb Free

G : Green (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.

Marking Information

For marking information, contact our sales representative directly or through a Richtek distributor located in your area.

Applications

zPortable Instruments

zMicroprocessors and DSP Core supplies

zCellular Telephones

zWireless and DSL Modems

zDigital Cameras

zPC Cards

Pin Configurations

 

(TOP VIEW)

 

 

NC LX LX LX

 

 

16

15

14

13

 

PGND

1

 

 

12

PVDD

PGND

2

PGND

11

PVDD

PGND

3

10

PVDD

 

17

FB

4

 

9

VDD

 

 

 

5

6

7

8

 

 

GND

NC

EN NC

 

 

WQFN-16L 3x3

 

DS8058-05 April 2011

www.richtek.com

 

1

RT8058

Typical Application Circuit

 

 

 

 

 

 

 

 

 

 

 

 

RT8058

 

 

L1

 

 

 

 

 

 

 

VIN

10,11,12

PVDD

 

LX

13,14,15

3.3µH

 

 

 

 

 

 

VOUT

 

 

 

 

 

 

 

 

2.6V to 5.5V

 

 

7

EN

 

 

 

 

R1

 

 

 

 

1.2V/2A

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

100k

 

 

 

 

 

 

 

 

 

9

VDD

 

FB

4

 

 

 

 

COUT1

 

 

COUT2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CIN

 

 

 

 

 

 

 

 

 

 

 

 

 

R2

 

22µF

 

22µF

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

10µF

 

GND

PGND

 

 

 

 

 

 

 

 

 

 

 

 

 

 

100k

 

 

 

 

 

 

 

 

 

 

 

 

 

 

5

 

1, 2, 3,

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Exposed Pad (17)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Functional Pin Description

Pin No.

Pin Name

Pin Function

1, 2, 3

 

Power Ground. Connect this pin close to the (–) terminal of CIN and COUT. The

17 (Exposed Pad)

PGND

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

 

 

maximum power dissipation.

4

FB

Feedback Input Pin. Receives the feedback voltage from a resistive divider

connected across the output.

 

 

5

GND

Signal Ground. Return the feedback resistive dividers to this ground, which in turn

connects to PGND at one point.

 

 

6, 8, 16

NC

No Internal Connection.

7

EN

Enable pin. A logical high level at this pin enables the converter, while a logical

low level causes the converter to shut down.

 

 

 

 

Signal Input Supply. Decouple this pin to GND with a capacitor. Normally VDD is

9

VDD

equal to PVDD. Keep the voltage difference between VDD and PVDD less than

 

 

0.5V.

10, 11, 12

PVDD

Power Input Supply of converter power stage. Decouple this pin to PGND with a

capacitor.

 

 

13, 14, 15

LX

Internal Power MOSFET Switches Output of converter. Connect this pin to the

inductor.

 

 

Function Block Diagram

 

 

 

 

ISEN

PVDD

 

 

 

 

 

 

 

 

 

 

 

OSC

Slope

 

 

 

 

 

 

Com

 

 

 

 

 

 

 

 

 

 

 

0.6V

EA

Output

 

OC

 

 

 

FB

Clamp

 

Limit

 

 

 

 

 

 

 

 

 

Int-SS

 

 

 

Driver

 

 

 

 

0.3V

 

Control

LX

 

 

 

 

 

 

 

 

 

 

 

 

Logic

 

 

 

 

 

 

 

OT

 

 

 

 

 

VREF

POR

 

PGND

 

 

 

 

Temp-SEN

 

 

 

 

 

 

 

 

GND

 

 

 

 

 

VDD

EN

 

 

 

www.richtek.com

 

 

 

 

DS8058-05

April

2011

2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RT8058

Absolute Maximum Ratings

(Note 1)

 

 

 

 

 

 

 

z Supply Input Voltage VDD, PVDD -------------------------------------------------------------------------------------

 

 

 

 

 

−0.3V to 6V

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

 

 

 

 

 

 

−0.3V to 6V

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

 

 

 

 

 

 

−0.3V to 6V

z Power Dissipation, PD @ TA = 25°C

 

 

 

 

 

 

 

 

 

WQFN-6L 3x3 --------------------------------------------------------------------------------------------------------------

 

 

 

 

 

 

1.471W

 

 

z Package Thermal Resistance (Note 2)

 

 

 

 

 

 

 

 

 

WQFN-16L 3x3, θJA -------------------------------------------------------------------------------------------------------

 

 

 

 

 

 

68°C/W

 

 

WQFN-16L 3x3, θJC ------------------------------------------------------------------------------------------------------

 

 

 

 

 

 

7°C/W

 

 

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

 

 

 

 

 

260°C

 

 

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

 

 

 

 

 

 

65°C to 150°C

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

 

 

 

 

 

 

150°C

 

 

z ESD Susceptibility (Note 3)

 

 

 

 

 

 

 

 

 

 

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

 

 

 

 

 

 

2kV

 

 

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

 

 

 

 

 

 

200V

 

 

Recommended Operating Conditions

(Note 4)

 

 

 

 

 

 

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

 

 

 

 

 

 

2.6V to 5.5V

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

 

 

 

 

 

 

−40°C to 125°C

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

 

 

 

 

 

 

−40°C to 85°C

Electrical Characteristics

 

 

 

 

 

 

 

 

 

(VDD = VPVDD = 3.6V, TA = 25°C, unless otherwise specified)

 

 

 

 

 

 

 

Parameter

Symbol

 

Test Conditions

Min

Typ

Max

 

Unit

 

 

 

 

 

 

 

 

 

 

 

 

Input Voltage Range

VIN

 

 

 

2.6

--

5.5

 

V

 

Feedback Voltage

VFB

 

 

 

0.582

0.6

0.618

 

V

 

DC Bias Current

 

 

Active, No Load

--

3.4

--

 

mA

 

 

 

 

 

 

 

 

 

 

 

 

 

Active, Not Switching, VFB = 0.5V

--

340

--

 

μA

 

(PVDD, VDD total)

 

 

 

 

 

 

Shutdown, EN = 0

--

--

2

 

μA

 

 

 

 

 

 

Under voltage Lockout

UVLO

 

VDD Rising

2.3

2.43

2.55

 

V

 

Threshold

 

VDD Hysteresis

--

150

--

 

mV

 

 

 

 

 

Oscillator Frequency

fOSC

 

Switching Frequency

0.75

1.0

1.25

 

MHz

 

EN High-Level Input Voltage

VEN_H

 

 

 

1.4

--

--

 

V

 

EN Low-Level Input Voltage

VEN_L

 

 

 

--

--

0.4

 

V

 

Switch On Resistance, High

RDS(ON)_P

 

IOUT = 200mA

--

142

210

 

Ω

 

 

 

 

m

 

Switch On Resistance, Low

RDS(ON)_N

 

IOUT = 200mA

--

96

160

 

 

Peak Current Limit

ILIM

 

 

 

2.2

3

--

 

A

 

Output Voltage Line Regulation

 

 

VIN = 2.6V to 5.5V

--

0.05

--

 

%/V

 

Output Voltage Load Regulation

 

 

ILOAD = 0A

Æ

--

0.15

--

 

%/A

 

 

 

 

2A

 

 

 

 

 

 

DS8058-05 April 2011

www.richtek.com

 

3

RT8058

Note 1. Stresses listed as the above “Absolute Maximum Ratings” may cause permanent damage to the device. These are for stress ratings. 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 for extended periods may remain possibility to affect device reliability.

Note 2. θJA is measured in the natural convection at TA = 25°C on a high effective four layers thermal conductivity test board of JEDEC 51-7 thermal measurement standard. The case point of θJC is on 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.

www.richtek.com

DS8058-05 April 2011

4

 

Richtek RT8058GQW, RT8058PQW Schematic

RT8058

Typical Operating Characteristics

Efficiency vs. Output Current

 

100

 

 

 

VIN = 5V

 

90

 

 

 

 

 

 

 

 

 

80

 

 

VIN = 3.3V

 

70

 

 

(%)

 

 

 

 

60

 

 

 

 

Efficiency

50

 

 

 

 

40

 

 

 

 

30

 

 

 

 

 

 

 

 

 

 

20

 

 

 

 

 

10

VOUT = 1.8V, L = 3.3μH, COUT = 22μFx2

 

0

 

 

 

 

 

 

0

500

1000

1500

2000

Efficiency vs. Output Current

 

100

 

 

 

 

 

90

 

 

 

VIN = 5V

 

80

 

 

 

 

(%)

70

 

 

VIN = 3.3V

60

 

 

 

 

Efficiency

50

 

 

 

 

40

 

 

 

 

30

 

 

 

 

 

 

 

 

 

 

20

 

 

 

 

 

10

VOUT = 1.2V, L = 3.3μH, COUT = 22μFx2

 

0

 

 

 

 

 

 

0

500

1000

1500

2000

Output Current (mA)

Output Current (mA)

 

1.2000

Output Voltage

vs. Outout Current

 

0.6010

 

 

 

 

 

 

 

 

 

 

1.1998

 

 

 

 

 

 

 

 

0.6008

Output Voltage (V)

1.1996

 

 

 

 

 

 

 

Reference Voltage (V)

0.6006

1.1994

 

VIN = 5V

 

 

 

 

0.6004

1.1992

 

 

 

 

 

 

 

0.6002

1.1990

 

 

 

 

 

 

 

0.6000

1.1988

 

VIN = 3.3V

 

 

 

0.5998

1.1986

 

 

 

 

0.5996

 

 

 

 

 

 

 

1.1984

 

 

 

 

 

 

 

0.5994

 

1.1982

 

 

 

 

 

 

 

 

0.5992

 

1.1980

 

 

 

 

 

 

 

 

0.5990

 

0

250

500

750

1000

1250

1500

1750

2000

 

Reference Voltage vs. Input Voltage

2.7

3.1

3.5

3.9

4.3

4.7

5.1

5.5

Outout Current (mA)

Output Voltage vs. Temperature

 

1.205

 

 

 

 

 

 

 

 

1.203

 

 

 

 

 

 

 

(V)

1.201

 

 

 

 

 

 

 

1.199

 

 

 

 

 

 

 

Voltage

1.197

 

 

 

 

 

 

 

1.195

 

 

 

 

 

 

 

1.193

 

 

 

 

 

 

 

Output

 

 

 

 

 

 

 

1.191

 

 

 

 

 

 

 

1.189

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1.187

 

 

 

 

 

VIN = 3.6V

 

1.185

 

 

 

 

 

 

 

 

 

 

 

 

 

 

-50

-25

0

25

50

75

100

125

Temperature (°C)

Input Voltage (V)

Frequency vs. Temperature

 

1100

 

 

 

 

 

 

 

 

1050

 

 

 

 

 

 

 

(kHz)

1000

 

 

 

 

 

 

 

Frequency

950

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

900

 

 

 

 

 

 

 

 

850

 

 

VIN = 3.6V, VOUT = 1.2V, IOUT = 0A

 

 

 

 

 

 

 

 

 

-50

-25

0

25

50

75

100

125

Temperature (°C)

DS8058-05 April 2011

www.richtek.com

 

5

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