Richtek RT8058AGQW Schematic [ru]

RT8058A

1.2MHz, 2A, High Efficiency PWM Step-Down DC/DC Converter

General Description

The RT8058Ais 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 1.2MHz 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 RT8058A operates at 100% duty cycle for low dropout operation that extends battery life in portable devices.

The RT8058A is available in a WDFN-10L 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

z1.2MHz Constant Switching Frequency

zLow RDS(ON) Internal Switches

zInternally Compensated

zInternal Soft-Start

zOver temperature Protection

zShort Circuit Protection

zSmall 10-Lead WDFN Package

zRoHS Compliant and Halogen Free

Ordering Information

RT8058A

Package Type

QW : WDFN-10L 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

E9= : Product Code

YMDNN : Data Code

E9=YM

DNN

Applications

zPortable Instruments

zMicroprocessors and DSP Core supplies

zCellular Telephones

zWireless and DSL Modems

zDigital Cameras

zPC Cards

Pin Configurations

(TOP VIEW)

PGND 1			10	LX
PGND 2			9	LX
FB 3		GND	8	PVDD
GND	4		7	VDD
POK	5	11	9	EN

WDFN-10L 3x3

DS8058A-02 April 2011	www.richtek.com
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RT8058A

Typical Application Circuit

VIN

8

RT8058A

L1

PVDD

9, 10

3.3µH

VOUT

2.6V to 5.5V

LX

6

EN

R1

1.2V/2A

C1

C2

R3

7

VDD

100k

3

10µF

1µF

100k

5

FB

C3

C4

POK

R2

22µF

1µF

GND

PGND

PGOOD

100k

4

1, 2,

11 (Exposed Pad)

Functional Pin Description

Pin No.

Pin Name

Pin Function

1, 2,

PGND

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

11 (Exposed Pad)

pad should be soldered to PCB board and connected to GND.

3

FB

Feedback Input Pin.

Receives

the feedback voltage from

a resistive divider

connected across the output.

4

GND

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

connects to PGND at one point.

5

POK

Power Good Indicator. Open-drain logic output that is opened when the output

voltage exceeds 90% of the regulation point.

6

EN

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

level causes the converter to shut down.

7

VDD

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

equal to PVDD.

8

PVDD

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

capacitor.

9, 10

LX

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

inductor.

Function Block Diagram

PVDD

Current Sense

OSC

Slope

Com

0.6V

OC

EA

Output

FB

Clamp

Limit

Driver

Int-SS

LX

0.3V

Control

UV

Logic

PGND

0.533V

VREF

POR

OTP

GND

POK

VDD EN

www.richtek.com

DS8058A-02 April 2011

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						RT8058A
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
WDFN-10L 3x3 -------------------------------------------------------------------------------------------------------------							1.429W
z Package Thermal Resistance (Note 2)
WDFN-10L 3x3, θJA -------------------------------------------------------------------------------------------------------							70°C/W
WDFN-10L 3x3, θJC -------------------------------------------------------------------------------------------------------							7.8°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 Reference Voltage	VREF				0.582	0.6	0.618		V
DC Bias Current			Active, No Load		--	3.4	--		mA
			Active, Not Switching, VFB = 0.5V		--	340	--		μ
(PVDD, VDD total)									A
			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		1	1.2	1.4		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		mΩ
Switch On Resistance, Low	RDS(ON)_N		IOUT = 200mA		--	96	160		mΩ
Peak Current Limit	ILIM				2.2	3	--		A
Output Voltage Line Regulation			VIN = 2.6V to 5.5V, IOUT = 0		--	0.05	--		%/V
Output Voltage Load			Æ	2A	--	1	--		%/A
			IOUT = 0A

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RT8058A

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.

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RT8058A

Typical Operating Characteristics

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 = 22μF
	0
	0	0.25	0.5	0.75	1	1.25	1.5	1.75	2

Output Current (A)

Output Voltage vs. Input Voltage

	1.200
	1.199
(V)	1.198
	1.197
Voltage	1.196
	1.195
Output	1.194
	1.193
	1.192
	1.191					IOUT = 0A
	1.190
	2.5	3	3.5	4	4.5	5	5.5

Input Voltage (V)

Switching Frequency vs. Input Voltage

	1.40
(MHz)	1.35
	1.30
Frequency	1.25
	1.20
	1.15
Switching
	1.10
	1.05
	1.00			VOUT = 1.2V, IOUT = 300mA
	2.5	3	3.5	4	4.5	5	5.5

Input Voltage (V)

Output Voltage vs. Output Current

	1.196
	1.195
(V)	1.194
Voltage	1.193		VIN = 5V
	1.192	VIN = 3.3V
Output	1.191
	1.190
	1.189
	1.188			VOUT = 1.2V, L = 3.3μH, COUT = 22μF
	0	0.25	0.5	0.75	1	1.25	1.5	1.75	2

Output Current (A)

FB Voltage vs. Temperature

	0.600
	0.598
	0.596
(V)	0.594
	0.592
Voltage
	0.590
	0.588
FB
	0.586
	0.584
	0.582					VIN = 3.3V, IOUT = 0A
	0.580
	-50	-25	0	25	50	75	100	125

Temperature (°C)

Switching Frequency vs. Temperature

	1.40
(MHz)	1.35
	1.30
Frequency	1.25
	1.20
	1.15
Switching
	1.10
	1.05
	1.00		VIN = 3.3V, VOUT = 1.2V, IOUT = 300mA
	-50	-25	0	25	50	75	100	125

Temperature (°C)

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