Richtek RT8058GQW, RT8058PQW Schematic [ru]

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

applicati

ons 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.

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 require-

ments 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.

Features

zz

0.6V Reference Allows Low Output Voltage

z

zz

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z Low Dropout Operation : 100% Duty Cycle

zz

zz

z 2A Load Current

zz

μμ

zz

z <2

μA Shutdown Current

zz

μμ

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z Up to 95% Efficiency

zz

zz

z No Schottky Diode Required

zz

zz

z 1MHZ Constant Switching Frequency

zz

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z Low R

zz

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z Internally Compensated

zz

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z Internal Soft-Start

zz

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z Over temperature Protection

zz

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z Short Circuit Protection

zz

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z Small 16-Lead WQFN Package

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z RoHS Compliant and 100% Lead (Pb)-Free

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Internal Switches

DS(ON)

Applications

z Portable Instruments

z Microprocessors and DSP Core supplies

z Cellular Telephones

z Wireless and DSL Modems

z Digital Cameras

z PC Cards

Pin Configurations

(TOP VIEW)

NC

LXLXLX

13141516

PVDD

NC

17

EN

12

11

PVDD

10

PVDD
VDD

9

8765

NC

PGND

PGND
PGND

FB

1

2

PGND

3

4

GND

WQFN-16L 3x3

DS8058-05 April 2011 www.richtek.com

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RT8058

Typical Application Circuit

L1

3.3µH

V

2.6V to 5.5V

IN

C

IN

10µF

10,11,12

7

9

RT8058

PVDD

EN

VDD

GND

5

13,14,15

LX

4

FB

PGND

1, 2, 3,
Exposed Pad (17)

Functional Pin Description

Pin No. Pin Name Pin Function

1, 2, 3

17 (Expos ed Pad)

PGND

4 FB

5 GND

6, 8, 16 NC No Internal Connection.

7 EN

9 VD D

10, 11 , 1 2 PV DD

13, 14, 15 LX

Power Ground. Connect this pin close to the (–) terminal of C
exposed pad must be soldered to a large PCB and connected to PGND for
maximum power dissipation.

Feedback Input Pin. Receives the feedback voltage from a resistive divider
connected across the output.
Signal Ground. Return the feedback resistive dividers to this ground, which in turn
connects to PGND at one point.

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 wi th a capacitor. Normally VDD is
equal to PVDD. Keep the voltage difference between VDD and PVDD less than

0.5V.
Power Input Supply of converter power stage. Decouple this pin to PGND with a
capacitor.
Internal Power MOSFET Switches Output of converter. Connect this pin to the
inductor.

R1

100k

R2
100k

C

OUT1

22µF

C

OUT2

22µF

V

OUT

1.2V/2A

and C

IN

OUT

. The

Function Block Diagram

0.6V

FB

EA

Int-SS

2

Output
Clamp

0.3V

OSC

VREF

Slope
Com

POR

VDD

Control

Logic

EN

ISEN

OC

Limit

OT

Temp-SEN

PVDD

Driver

LX

PGND

GND

DS8058-05 April 2011www.richtek.com

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, P

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

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

@ TA = 25°C

D

−40°C to 125°C

−40°C to 85°C

Electrical Characteristics

(V

= V

DD

Input Voltage Range

Feedback Voltage

DC Bias Current
(PVDD, VDD total)

Under voltage Lockout

Threshold

Oscillator Frequency

EN High-Level Input Voltage

EN Low-Level Input Voltage

Switch On Resistance, High R

Switch On Resistance, Low R

Peak Current Limit I

Output Voltage Line Regulation

Output Voltage Load Regulation

PVDD

= 3.6V, T

= 25°C, unless otherwise specified)

A

Parameter Symbol Test Conditions Min Typ Max Unit

V

IN

V

FB

UVLO

f

OSC

V

EN_H

V

EN_L

DS(ON)_P

DS(ON)_N

LIM

2.6 - - 5.5 V

0.582 0.6 0.618 V

Active, No Load -- 3.4 -- mA

Active, Not Switching, VFB = 0.5V

Shutdown, EN = 0 -- -- 2

VDD Rising

Hysteresis

V

DD

Switching Frequency

1.4 -- -- V

-- -- 0.4 V

I

I

= 200mA

OUT

= 200mA -- 96 160 mΩ

OUT

-- 340 -- μA
μA

2.3 2.43 2.55 V

-- 150 -- mV

0.75 1.0 1.25 MHz

--

142 210 mΩ

2.2 3 -- A

V

= 2.6V to 5.5V

IN

I

= 0AÆ2A

LOAD

-- 0.05 -- %/V

--

0.15 -- %/A

DS8058-05 April 2011 www.richtek.com

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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. θ

Note 3. Devices are ESD sensitive. Handling precaution is recommended.
Note 4. The device is not guaranteed to function outside its operating conditions.

is measured in the natural convection at TA = 25°C on a high effective four layers thermal conductivity test board of

JA

JEDEC 51-7 thermal measurement standard. The case point of θ

is on the exposed pad of the package.

JC

DS8058-05 April 2011www.richtek.com

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Typical Operating Characteristics

RT8058

1.2000

1.1998

1.1996

1.1994

1.1992

1.1990

1.1988

1.1986

Output Voltage (V)

1.1984

1.1982

1.1980

Efficiency vs. Output Current

100

90

80

70

60

50

40

Efficiency (%)

30

20

10

0

0 500 1000 1500 2000

V

= 1.8V, L = 3.3μH, C

OUT

OUT

Output Current (mA)

Output Voltage vs. Outout Current

VIN = 5V

VIN = 3.3V

0 250 500 750 1000 1250 1500 1750 2000

Outout Current (mA)

VIN = 5V

VIN = 3.3V

= 22μFx2

0.6010

0.6008

0.6006

0.6004

0.6002

0.6000

0.5998

0.5996

0.5994

Reference Voltage (V)

0.5992

0.5990

Efficiency vs. Output Current

100

90

80

70

60

50

40

Efficiency (%)

30

20

10

0

0 500 1000 1500 2000

V

= 1.2V, L = 3.3μH, C

OUT

OUT

Output Current (mA)

Reference Voltage vs. Input Voltage

2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5

Input Voltage (V)

VIN = 5V

VIN = 3.3V

= 22μFx2

Output Voltage vs. Temperature

1.205

1.203

1.201

1.199

1.197

1.195

1.193

1.191

Output Voltage (V)

1.189

1.187

1.185

-50 -25 0 25 50 75 100 125

Temp erature

(°C)

VIN = 3.6V

1100

1050

1000

950

Frequency (kHz)

900

850

-50 -25 0 25 50 75 100 125

Frequency vs. Temperature

VIN = 3.6V, V

Temp erature

= 1.2V, I

OUT

(°C)

OUT

= 0A

DS8058-05 April 2011 www.richtek.com

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