Richtek RT8205AGQW, RT8205BGQW, RT8205CGQW Schematic [ru]

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®

RT8205A/B/C

High Efficiency, Main Power Supply Controllers for Notebook Computers

General Description

The RT8205A/B/C dual step-down, switch-mode powersupply controller generates logic-supply voltages in battery-powered systems. The RT8205A/B/C includes two pulse-width modulation (PWM) controllers fixed at 5V/ 3.3V or adjustable from 2V to 5.5V. An alternative LGATE1 output LG1_CP can be used for external charge pump (RT8205B). And an optional external charge pump can be monitored through SECFB (RT8205C). This device also features 2 linear regulators providing fixed 5V and 3.3V outputs. The linear regulator each provides up to 70mA output current with automatic linear-regulator bootstrapping to the PWM outputs. The RT8205A/B/C includes on-board power-up sequencing, the power-good output, internal softstart, and internal soft-discharge output that prevents negative voltages on shutdown.

A constant on-time PWM control scheme operates without sense resistor and provides 100ns response to load transients while maintaining a relatively constant switching frequency. The unique ultrasonic mode maintains the switching frequency above 25kHz, which eliminates noise in audio applications. Other features include diodeemulation mode (DEM), which maximizes efficiency in light-load applications, and fixed-frequency PWM mode, which reduces RF interference in sensitive application

Features

zWide Input Voltage Range 6V to 25V

zDual Fixed 5V/3.3V Outputs or Adjustable from 2V to 5.5V, 1.5% Accuracy.

zAlternative LGATE1 Output (LG1_CP) acts as Clock for Charge Pump (RT8205B)

zSecondary Feedback Input Maintains Charge Pump Voltage (RT8205C)

zFixed 3.3V and 5V LDO Output : 70mA

z2V Reference Voltage ±1% : 50μA

zConstant ON-Time Control with 100ns Load Step Response

zFrequency Selectable via TONSEL Setting

zRDS(ON) Current Sensing and Programmable Current Limit combined with Enable Control

zSelectable PWM, DEM, or Ultrasonic Mode

zInternal Soft-Start and Soft-Discharge

zHigh Efficiency up to 97%

z5mW Quiescent Power Dissipation

zThermal Shutdown

zRoHS Compliant and Halogen Free

Applications

zNotebook and Sub-Notebook Computers

z3-Cell and 4-Cell Li+ Battery-Powered Devices

Ordering Information

RT8205

Package Type

QW : WQFN-24L 4x4 (W-Type)

Lead Plating System

G : Green (Halogen Free and Pb Free)

Pin Function

A : Default

B : With LG1_CP

C : With SECFB

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.

DS8205A/B/C-06 July 2012

www.richtek.com

 

1

RT8205A/B/C

Marking Information

RT8205AGQW

 

RT8205BGQW

 

RT8205CGQW

 

 

 

 

CJ= : Product Code

 

 

 

CK= : Product Code

 

 

 

CL= : Product Code

 

CJ=YM

 

YMDNN : Date Code

 

CK=YM

 

YMDNN : Date Code

 

CL=YM

 

YMDNN : Date Code

 

DNN

 

 

 

DNN

 

 

 

DNN

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Pin Configurations

 

VOUT1

PGOOD

BOOT1

UGATE1

PHASE1

LGATE1

 

 

24

23

22

21

20

19

 

ENTRIP1

1

 

 

 

 

18

NC

FB1

2

 

 

 

 

17

VREG5

REF

3

 

GND

 

16

VIN

TONSEL

4

 

 

15

GND

 

 

 

 

FB2

5

 

 

 

25

14

SKIPSEL

ENTRIP2

6

 

 

 

 

13

EN

 

7

8

9

10

11

12

 

 

VOUT2

VREG3

BOOT2

UGATE2

PHASE2

LGATE2

 

 

 

RT8205A

 

 

 

WQFN-24L 4x4

 

 

(TOP VIEW)

 

 

VOUT1

PGOOD

BOOT1

UGATE1

PHASE1

LGATE1

 

 

24

23

22

21

20

19

 

ENTRIP1

1

 

 

 

 

18

LG1_CP

FB1

2

 

 

 

 

17

VREG5

REF

3

 

GND

 

16

VIN

TONSEL

4

 

 

15

PGND

 

 

 

 

FB2

5

 

 

 

25

14

SKIPSEL

ENTRIP2

6

 

 

 

 

13

EN

 

7

8

9

10

11

12

 

 

VOUT2

VREG3

BOOT2

UGATE2

PHASE2

LGATE2

 

 

 

RT8205B

 

 

 

WQFN-24L 4x4

 

 

VOUT1

PGOOD

BOOT1

UGATE1

PHASE1

LGATE1

 

 

24

23

22

21

20

19

 

ENTRIP1

1

 

 

 

 

18

SECFB

FB1

2

 

 

 

 

17

VREG5

REF

3

 

GND

 

16

VIN

TONSEL

4

 

 

15

PGND

 

 

 

 

FB2

5

 

 

 

25

14

SKIPSEL

ENTRIP2

6

 

 

 

 

13

EN

 

7

8

9

10

11

12

 

 

VOUT2

VREG3

BOOT2

UGATE2

PHASE2

LGATE2

 

 

 

RT8205C

 

 

 

WQFN-24L 4x4

 

Typical Application Circuit

For Fixed Voltage Regulator

C1

R7

3.9

10uF

 

 

C6

 

0.1uF

V

 

L1

OUT1

6.8uH

 

5V

 

 

C3

R5

 

220uF

 

 

 

C4

Q1

R4 0

BSC119

 

 

N03S

R3

0

 

C2

 

 

0.1uF

 

Q3

BSC119

N03S

C11 0.22uF

Frequency Control

PWM/DEM/Ultrasonic

ON

OFF

 

RT8205A

 

16

VIN

UGATE2

10

 

 

BOOT2

9

21

UGATE1

PHASE2

11

 

 

 

22

BOOT1

LGATE2

12

 

 

 

 

V

 

 

 

 

IN

R9

 

C9

C8

 

0

Q2

10uF

10uF

 

 

BSC119

 

 

R8

0

N03S

 

 

 

 

C7

L2

V

 

 

0.1uF

4.7uH

 

 

 

 

OUT2

 

 

Q4

 

3.3V

 

 

R10

C13

 

 

BSC119

220uF

 

 

 

 

 

N03S

C10

 

 

 

 

 

20 PHASE1

19 LGATE1

24 VOUT1

3REF

4TONSEL

14 SKIPSEL

13 EN

2 FB1

5 FB2

VOUT2 7 VREG5 17

PGOOD 23 VREG3 8

ENTRIP1 1

ENTRIP2 6

C5

5V Always On

R6

4.7uF

100k

 

 

PGOOD Indicator

C12

3.3V Always On

R1

4.7uF

 

150k

 

R2

 

150k

GND 15, Exposed Pad (25)

Copyright ©2012 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

www.richtek.com

DS8205A/B/C-06 July 2012

2

 

Richtek RT8205AGQW, RT8205BGQW, RT8205CGQW Schematic

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RT8205A/B/C

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

IN

 

 

 

C1

 

 

R7

 

 

RT8205B

 

R9

 

 

C13

C12

 

 

 

 

 

3.9

 

 

 

 

 

 

 

 

10uF

 

 

 

 

16

VIN

 

UGATE2

10

 

0

Q2

 

10uF

10uF

 

 

 

 

 

 

C10

 

 

 

 

BSC119

 

 

 

 

 

 

 

 

 

 

 

 

 

R8

0

N03S

 

 

 

 

 

 

 

 

 

0.1uF

 

 

 

BOOT2

9

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R4 0

 

 

 

 

 

 

C7

 

 

L2

 

 

 

 

 

 

Q1

21

UGATE1

PHASE2

11

 

0.1uF

 

 

4.7uH

V

 

 

 

 

BSC119

 

 

 

 

 

 

 

 

OUT2

 

 

 

 

N03S

R3

0

22 BOOT1

 

 

12

 

 

Q4

 

 

3.3V

 

 

 

 

 

LGATE2

 

 

 

R10

C17

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C2

 

 

 

 

 

 

 

 

 

BSC119

 

220uF

 

 

 

L1

 

 

 

 

 

 

 

 

 

 

N03S

 

C14

 

V

 

 

 

0.1uF

 

 

 

 

 

 

 

 

 

 

 

 

6.8uH

 

 

 

 

 

 

 

 

 

 

 

 

 

 

OUT1

 

 

 

 

 

 

20 PHASE1

 

 

 

 

 

 

 

 

 

5V

 

 

 

 

 

 

VOUT2

7

 

 

 

 

 

 

 

C3

 

R5

 

Q3

 

 

19 LGATE1

 

 

 

 

 

 

 

 

 

 

 

VREG5

17

 

 

 

5V Always On

 

 

220uF

 

 

BSC119

 

 

 

 

 

 

C9

 

 

 

 

 

C4

N03S

 

 

 

 

 

 

 

 

R6

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4.7uF

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

100k

 

 

 

 

 

 

 

 

 

 

 

24 VOUT1

 

PGOOD 23

 

 

 

 

 

 

 

 

 

 

C5

 

 

 

 

 

 

PGOOD Indicator

 

 

 

 

D1

 

 

 

 

 

VREG3 8

 

 

 

3.3V Always On

 

C6

 

 

 

0.1uF

 

 

18 LG1_CP

 

 

 

C16

R1

 

 

 

 

 

D2

 

 

 

 

 

 

 

4.7uF

 

 

 

 

0.1uF

 

 

 

 

 

 

 

ENTRIP1

1

 

 

150k

 

 

 

 

 

 

C7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

D3

 

 

3 REF

 

 

 

 

 

 

 

 

 

 

 

0.1uF

C15

 

 

 

 

 

R2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

150k

 

 

 

 

 

 

D4

 

 

0.22uF

 

 

 

ENTRIP2 6

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C8

 

BAT254

 

ON

 

13 EN

 

PGND

15

 

 

 

 

 

 

 

0.1uF

 

 

OFF

 

 

 

2

 

 

 

 

 

 

 

 

 

CP

 

 

 

 

 

 

FB1

 

 

 

 

 

 

 

 

 

 

Frequency Control

 

4 TONSEL

 

 

 

 

 

 

 

 

 

 

 

 

FB2

5

 

 

 

 

 

 

 

 

 

 

PWM/DEM/Ultrasonic

 

14 SKIPSEL

 

 

 

 

 

 

 

 

 

 

 

GND

Exposed Pad (25)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

V

 

 

 

 

 

 

R8

 

 

 

 

 

 

 

 

 

 

IN

 

 

 

C1

 

 

 

 

RT8205C

 

R10

 

 

C13

C12

 

 

 

 

 

3.9

 

 

 

 

 

 

 

 

10uF

 

 

 

 

16

VIN

 

UGATE2

10

 

0

Q2

 

10uF

10uF

 

 

 

 

 

 

C10

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R9

0

BSC119

 

 

 

 

 

 

 

 

0.1uF

 

 

 

BOOT2

9

N03S

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R4 0

 

 

 

 

 

 

C11

 

 

L2

 

 

 

 

 

 

Q1

21 UGATE1

PHASE2

11

 

0.1uF

 

 

4.7uH

VOUT2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BSC119

R3

0

 

 

 

 

 

 

 

 

 

3.3V

 

 

 

 

N03S

22 BOOT1

 

LGATE2

12

 

 

Q4

 

R11

C17

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C2

 

 

 

 

 

 

 

 

 

BSC119

 

220uF

 

 

 

L1

 

 

 

 

 

 

 

 

 

 

N03S

 

C14

 

V

 

 

 

0.1uF

 

 

 

 

 

 

 

 

 

 

 

OUT1

6.8uH

 

 

 

20 PHASE1

 

7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VOUT2

 

 

 

 

 

 

 

C3

 

R5

 

Q3

 

 

19 LGATE1

 

 

 

 

 

 

 

 

 

 

 

VREG5

17

 

 

 

5V Always On

 

 

220uF

 

 

BSC119

 

 

 

 

 

 

C9

 

 

 

 

 

C4

N03S

 

 

 

 

 

 

 

 

R6

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4.7uF

 

 

 

 

 

 

 

 

 

 

 

24 VOUT1

 

PGOOD 23

 

 

100k

 

 

 

 

 

 

 

 

C5

 

 

 

 

 

 

PGOOD Indicator

 

 

 

 

D1

 

 

3 REF

 

VREG3

8

 

C16

 

3.3V Always On

 

C6

 

 

 

0.1uF

 

 

 

 

 

 

 

 

 

 

 

 

D2

 

 

C15

 

 

 

 

 

 

4.7uF

R1

 

 

 

 

0.1uF

 

 

0.22uF

 

 

 

ENTRIP1

1

 

 

150k

 

 

 

 

 

 

C7

 

 

 

 

 

 

 

 

 

 

 

 

D3

 

 

2 FB1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0.1uF

 

 

 

 

 

 

 

R2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

D4

 

 

 

 

5 FB2

 

ENTRIP2 6

 

 

150k

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C8

 

BAT254

R6

 

 

 

 

 

TONSEL 4

 

Frequency Control

 

 

 

 

0.1uF

 

 

200k

 

 

18 SECFB

 

SKIPSEL

14

 

PWM/DEM/Ultrasonic

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

15

 

 

 

 

 

 

 

 

 

CP

 

 

 

39k

 

 

 

PGND

 

 

 

 

 

 

 

 

 

 

C18

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ON

 

 

 

 

 

GND

Exposed Pad (25)

 

 

 

 

 

 

 

 

 

 

 

13 EN

 

 

 

 

 

 

 

 

OFF

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Copyright ©2012 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

DS8205A/B/C-06 July 2012

www.richtek.com

3

RT8205A/B/C

For Adjustable Voltage Regulator

V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

IN

 

 

 

C1

 

R7

 

 

RT8205A

 

R9

 

 

 

C9

C8

 

 

 

 

 

 

3.9

 

 

 

 

 

 

 

 

 

 

10uF

 

 

 

16

VIN

 

UGATE2 10

 

0

 

Q2

10uF

10uF

 

 

 

 

 

 

 

 

C6

 

 

 

 

BSC119

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R8

0

 

N03S

 

 

 

 

 

 

 

 

 

 

 

0.1uF

 

 

 

BOOT2 9

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R4 0

 

 

 

 

 

 

 

C7

 

 

L2

 

 

 

 

 

 

 

Q1

21 UGATE1

PHASE2

11

 

 

0.1uF

 

 

4.7uH

 

 

VOUT2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BSC119

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3.3V

 

 

 

 

N03S

R3

0

22 BOOT1

LGATE2 12

 

 

 

Q4

 

 

 

 

 

 

 

 

 

 

 

R10

 

C13

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C2

 

 

 

 

 

 

 

 

 

BSC119

 

 

 

220uF

 

 

L1

 

 

 

 

 

 

 

 

 

 

N03S

C10

 

 

 

 

 

0.1uF

 

 

 

 

 

 

 

 

 

 

 

 

V

OUT1

6.8uH

 

20 PHASE1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

5V

 

 

 

 

 

VOUT2 7

 

 

 

 

 

 

 

 

 

 

C3

 

 

Q3

 

 

19

LGATE1

 

 

 

 

 

 

 

 

 

 

 

R5

 

 

FB2 5

 

 

 

 

 

 

R13

 

C17

 

220uF

 

BSC119

 

 

 

 

R1

 

 

 

 

 

 

 

 

 

N03S

 

 

 

 

 

 

 

 

 

 

 

 

6.5k

 

 

 

 

 

C4

 

 

 

 

 

ENTRIP1 1

 

150k

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C16

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

24 VOUT1

 

 

 

R2

 

 

 

 

R14

 

0.1uF

 

C14

R11

 

 

 

 

 

 

 

ENTRIP2 6

 

150k

 

 

 

 

10k

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

15k

 

 

 

 

2

FB1

 

 

15, Exposed Pad (25)

 

 

 

 

 

 

 

C15

 

 

 

 

 

 

GND

 

 

 

 

 

 

 

R12

 

 

 

 

3

REF

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0.1uF

 

 

C11

 

 

VREG5 17

 

 

 

 

 

 

 

 

 

 

10k

 

 

 

 

 

 

 

 

 

5V Always On

 

 

 

 

 

 

 

0.22uF

 

 

 

 

 

C5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R6

 

 

 

 

 

 

 

 

Frequency Control

 

 

4 TONSEL

 

 

 

4.7uF

 

 

 

 

 

 

 

 

 

 

 

 

 

100k

 

 

 

 

 

 

 

 

 

 

PGOOD 23

 

 

 

 

 

 

 

 

 

 

 

PWM/DEM/Ultrasonic

 

 

14 SKIPSEL

 

 

 

PGOOD Indicator

 

 

 

 

 

 

ON

 

 

13 EN

 

VREG3 8

 

C12

 

3.3V Always On

 

 

 

 

 

 

OFF

 

 

 

 

 

 

 

 

4.7uF

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

IN

 

 

 

C1

 

 

R7

 

RT8205B

 

 

R9

 

 

C13

 

C12

 

 

 

 

 

 

3.9

 

 

 

 

 

 

 

 

 

 

10uF

 

 

 

 

16 VIN

UGATE2

10

0

 

Q2

 

10uF

10uF

 

 

 

 

 

 

 

C10

 

 

 

BSC119

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R8

0

N03S

 

 

 

 

 

 

 

 

 

 

 

0.1uF

 

 

BOOT2 9

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R4 0

 

 

 

 

 

 

C7

 

L2

 

 

 

 

 

 

 

Q1

 

21 UGATE1

PHASE2

11

 

0.1uF

 

4.7uH

 

VOUT2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BSC119

 

 

 

 

 

 

 

 

 

 

 

 

 

3.3V

 

 

 

 

N03S

 

R3

0

22 BOOT1

 

 

12

 

 

Q4

 

 

 

 

 

 

 

 

 

LGATE2

 

 

 

R10

 

 

C17

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C2

 

 

 

 

 

 

 

 

 

BSC119

 

 

 

220uF

 

 

 

L1

 

 

 

 

 

 

 

 

 

 

N03S

 

C14

 

 

 

 

 

 

 

0.1uF

 

 

 

 

 

 

 

 

 

 

 

 

 

OUT1

 

6.8uH

 

 

 

20 PHASE1

 

 

7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VOUT2

 

 

 

 

 

 

 

 

5V

 

 

Q3

 

 

 

19 LGATE1

 

 

 

 

 

 

 

 

 

C3

 

R5

 

 

 

 

 

 

 

 

 

 

 

 

R13

C21

220uF

 

 

BSC119

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C4

N03S

 

 

 

 

 

 

 

5

 

 

 

 

 

 

6.5k

 

 

 

 

 

 

 

 

 

 

FB2

 

 

 

 

 

 

 

C20

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R1

 

 

 

 

 

 

 

 

 

 

 

 

24 VOUT1

 

 

 

 

 

 

 

 

R14

0.1uF

 

C18

 

 

 

 

 

 

ENTRIP1

1

 

 

150k

 

 

 

 

 

R11

 

 

 

 

 

 

 

 

 

R2

 

 

 

10k

 

 

 

15k

 

 

 

 

 

2 FB1

 

 

 

 

 

 

 

 

 

 

 

C19

 

 

 

C5

 

 

ENTRIP2

6

 

 

150k

 

 

 

 

 

 

R12

 

D1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0.1uF

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0.1uF

 

 

 

 

 

 

Exposed Pad (25)

 

 

 

 

 

 

 

10k

 

 

 

 

18 LG1_CP

GND

 

 

 

 

 

 

 

 

C6

D2

 

 

 

 

 

 

 

 

 

 

 

0.1uF

 

 

 

 

 

 

 

17

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VREG5

 

 

 

 

 

 

 

 

 

 

 

 

D3

C7

 

 

3

REF

 

C9

 

5V Always On

 

 

 

 

 

 

0.1uF

 

C15

 

 

 

 

 

R6

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4.7uF

 

 

 

 

 

 

 

 

 

D4

 

 

0.22uF

 

 

 

 

 

100k

 

 

 

 

 

 

 

 

 

 

 

 

PGOOD

23

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PGOOD Indicator

 

 

 

 

C8

BAT254

 

ON

 

 

 

 

 

 

 

 

 

 

 

 

13 EN

VREG3

8

 

 

 

3.3V Always On

 

 

 

 

0.1uF

 

OFF

 

 

C16

 

 

 

 

 

 

CP

 

 

 

 

 

 

 

4.7uF

 

 

 

 

 

 

 

 

 

 

 

 

 

4 TONSEL

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Frequency Control

 

PGND

15

 

 

 

 

 

 

 

 

 

 

 

 

PWM/DEM/Ultrasonic

 

14 SKIPSEL

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Copyright ©2012 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

www.richtek.com

DS8205A/B/C-06 July 2012

4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RT8205A/B/C

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

V

 

 

 

 

 

R8

 

 

 

 

 

 

 

 

 

 

IN

 

C1

 

 

 

 

RT8205C

 

R10

 

 

C13

C12

 

 

 

 

 

3.9

 

 

 

 

 

 

10uF

 

 

 

 

 

16

VIN

UGATE2

10

 

0

Q2

 

10uF

10uF

 

 

 

 

 

 

C10

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R9

0

BSC119

 

 

 

 

 

 

 

 

0.1uF

 

 

BOOT2 9

N03S

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R4 0

 

 

 

 

 

C11

 

 

L2

 

 

 

 

 

 

Q1

21

UGATE1

 

11

 

0.1uF

 

 

4.7uH

 

V

 

 

 

BSC119

 

 

 

PHASE2

 

 

 

 

 

 

OUT2

 

 

 

R3

0

 

 

 

 

 

 

 

 

 

3.3V

 

 

 

N03S

22 BOOT1

LGATE2

12

 

 

Q4

 

R11

 

C17

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C2

 

 

 

 

 

 

 

 

BSC119

 

 

220uF

 

L1

 

 

 

 

 

 

 

 

 

 

N03S

 

C14

 

 

 

 

 

0.1uF

 

 

 

 

 

 

 

 

 

 

 

VOUT1

6.8uH

 

 

 

 

20 PHASE1

VOUT2 7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C3

R5

 

Q3

 

 

19 LGATE1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R14

C21

220uF

 

 

BSC119

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6.5k

 

 

C4

 

N03S

 

 

 

 

 

5

 

 

 

 

 

 

 

 

 

 

 

 

FB2

 

 

 

 

 

 

C20

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

24 VOUT1

 

 

 

R1

 

 

R15

0.1uF

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ENTRIP1 1

 

 

150k

 

 

 

C18

R12

 

 

 

 

 

 

 

 

 

 

 

 

10k

 

 

15k

 

 

 

 

 

2 FB1

 

 

 

 

R2

 

 

 

 

C19

 

 

 

 

 

 

ENTRIP2 6

 

 

150k

 

 

 

 

R13

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0.1uF

 

D1

C5

 

 

 

 

GND Exposed Pad (25)

 

 

 

 

 

10k

 

 

 

 

 

 

 

 

 

 

 

 

0.1uF

 

 

3

 

 

 

 

 

 

 

C6

D2

 

 

C15

REF

VREG5

17

 

 

 

5V Always On

 

 

 

0.1uF

 

 

 

 

 

C9

 

 

 

 

 

 

 

C7

0.22uF

 

 

 

 

 

R6

 

 

 

 

 

 

 

D3

 

 

 

 

 

 

 

4.7uF

 

 

 

 

 

 

 

0.1uF

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

100k

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

PGOOD 23

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

D4

 

 

 

 

 

 

 

 

 

PGOOD Indicator

 

 

C8

BAT254

R6

 

 

 

 

VREG3 8

 

C16

 

3.3V Always On

 

 

200k

 

 

 

 

 

 

 

 

 

 

 

 

 

0.1uF

 

 

 

 

18 SECFB

TONSEL 4

 

4.7uF

 

 

 

 

 

 

 

 

 

 

 

R7

 

 

 

Frequency Control

 

 

CP

 

C18

 

39k

 

SKIPSEL 14

 

 

 

PWM/DEM/Ultrasonic

 

 

 

 

 

 

 

 

 

 

 

OFF

ON

 

 

 

13 EN

PGND 15

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Copyright ©2012 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

DS8205A/B/C-06 July 2012

www.richtek.com

5

RT8205A/B/C

Function Block Diagram

 

TONSEL

SKIPSEL

 

BOOT1

 

 

BOOT2

UGATE1

 

 

UGATE2

PHASE1

VREG5

 

PHASE2

 

 

VREG5

 

SMPS1

SMPS2

 

LGATE1

PWM Buck

PWM Buck

LGATE2

Controller

Controller

PGND

 

 

 

VOUT1

 

 

VOUT2

FB1

 

 

FB2

ENTRIP1

 

 

ENTRIP2

 

Power-On

 

PGOOD

 

 

 

EN

Sequence

 

 

 

Clear Fault Latch

 

GND

 

 

 

 

SW Threshold

SW Threshold

 

Thermal

 

 

 

Shutdown

 

 

VREG5

 

 

VREG3

 

VREG5

REF

VREG3

VIN

 

 

 

 

 

REF

 

Function Block Diagram

TONSEL VIN

UGATE

VOUT

On-Time

TON

Q

R

TOFF

Compute

1-Shot

TRIG 1-Shot

 

 

 

Q

 

 

 

 

 

 

 

 

 

 

 

 

 

TRIG

 

 

REF

-

+

-

Comp

 

 

 

+

-

+

 

 

 

 

 

 

 

 

 

 

 

LGATE

FB

 

 

Over-Voltage

 

 

VREG5

1.1 x VREF

+

 

Fault

 

 

 

-

 

Latch

 

 

 

0.7 x VREF

-

 

Blanking

+

ENTRIP

 

+

 

Time

 

 

 

Under-Voltage

 

-

 

 

 

 

-

 

 

Current

 

 

 

 

 

 

+ Limit

 

 

0.9 x V

+

 

SS

 

 

 

REF

 

Time

-

 

 

 

 

 

 

-

 

 

 

 

 

 

 

+

 

PGOOD

 

 

 

 

25kHz

+

PHASE

 

 

 

 

 

 

Detector

 

 

 

 

 

 

Zero -

 

 

 

 

 

 

Detector

 

 

 

SKIPSEL

PWM Controller (One Side)

 

 

 

 

 

 

 

Copyright ©2012 Richtek Technology Corporation. All rights reserved.

 

is a registered trademark of Richtek Technology Corporation.

www.richtek.com

 

 

 

 

DS8205A/B/C-06 July 2012

6

RT8205A/B/C

Functional Pin Description

ENTRIP1 (Pin 1)

Channel 1 enable and Current Limit setting Input. Connect resistor to GND to set the threshold for channel 1 synchronous RDS(ON) sense. The GND-PHASE1 currentlimit threshold is 1/10th the voltage seen at ENTRIP1 over a 0.5V to 2V range. There is an internal 10uAcurrent source from VREG5 to ENTRIP1. The logic current limit threshold is default to 200mV value if ENTRIP1 is higher than VREG5-1V.

FB1 (Pin 2)

SMPS1 Feedback Input. Connect FB1 to VREG5 or GND for fixed 5V operation. Or connect FB1 to a resistive voltagedivider from VOUT1 to GND to adjust output from 2V to 5.5V.

REF (Pin 3)

2V Reference Output. Bypass to GND with a 0.22uF capacitor. REF can source up to 50uA for external loads. Loading REF degrades FBx and output accuracy according to the REF load-regulation error.

TONSEL (Pin 4)

Frequency Selectable Input for VOUT1/VOUT2 respectively.

400kHz/500kHz : Connect to VREG5 or VREG3

300kHz/375kHz : Connect to REF

200kHz/250kHz : Connect to GND

FB2 (Pin 5)

SMPS2 Feedback Input. Connect FB2 to VREG5 or GND for fixed 3.3V operation. Or connect FB2 to a resistive voltage-divider from VOUT2 to GND to adjust output from 2V to 5.5V.

ENTRIP2 (Pin 6)

Channel 2 enable and Current Limit setting Input. Connect resistor to GND to set the threshold for channel 2 synchronous RDS(ON) sense. The GND-PHASE2 currentlimit threshold is 1/10th the voltage seen at ENTRIP2 over a 0.5V to 2V range. There is an internal 10uAcurrent source

from VREG5 to ENTRIP2. The logic current limit threshold is default to 200mV value if ENTRIP2 is higher than VREG5-1V.

VOUT2 (Pin 7)

SMPS2 Output Voltage-Sense Input. Connect to the SMPS2 output. VOUT2 is an input to the on-time oneshot circuit. It also serves as the SMPS2 feedback input in fixed-voltage mode.

VREG3 (Pin 8)

3.3V Linear Regulator Output.

BOOT2 (Pin 9)

Boost Flying Capacitor Connection for SMPS2. Connect to an external capacitor according to the typical application circuits.

UGATE2 (Pin 10)

High-Side MOSFET Floating Gate-Driver Output for SMPS2. UGATE2 swings between PHASE2 and BOOT2.

PHASE2 (Pin 11)

Inductor Connection for SMPS2. PHASE2 is the internal lower supply rail for the UGATE2 high-side gate driver. PHASE2 is also the current-sense input for the SMPS2.

LGATE2 (Pin 12)

SMPS2 Synchronous-Rectifier Gate-Drive Output. LGATE2 swings between GND and VREG5.

EN (Pin 13)

Master Enable Input. The REF/VREG5/VREG3 are enabled if it is within logic high level and disable if it is less than the logic low level.

SKIPSEL (Pin 14)

Operation Mode Selectable Input.

Ultrasonic Mode : Connect to VREG5 or VREG3

Diode Emulation Mode : Connect to REF

PWM Mode : Connect to GND

Copyright ©2012 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

DS8205A/B/C-06 July 2012

www.richtek.com

 

7

RT8205A/B/C

GND [Pin 15 (RT8205A), Exposed Pad (25)]

Analog Ground for SMPS controller. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation.

PGND (Pin 15) (RT8205B/C)

Power Ground for SMPS controller. Connect PGND externally to the underside of the exposed pad.

VIN (Pin 16)

High Voltage Power Supply Input for 5V/3.3V LDO and Feed-forward ON-Time circuitry.

VREG5 (Pin 17)

5V Linear Regulator Output.VREG5 is also the supply voltage for the low-side MOSFET driver and analog supply voltage for the device.

NC (Pin 18) (RT8205A)

No Internal Connection.

LG1_CP (Pin 18) (RT8205B)

Alternative LGATE1 Output for 14V charge pump.

SECFB (Pin 18) (RT8205C)

The SECFB is used to monitor the optional external 14V charge pump. Connect a resistive voltage-divider from 14V charge pump output to GND to detect the output. If SECFB drops below the threshold voltage, LGATE1 turns on for 300ns (typ.). This will refresh the external charge pump driven by LGATE1 without over-discharging the output voltage.

LGATE1 (Pin 19)

SMPS1 Synchronous-Rectifier Gate-Drive Output. LGATE1 swings between GND and VREG5.

PHASE1 (Pin 20)

Inductor Connection for SMPS1. PHASE1 is the internal lower supply rail for the UGATE1 high-side gate driver. PHASE1 is also the current-sense input for the SMPS1.

UGATE1 (Pin 21)

High-Side MOSFET Floating Gate-Driver Output for SMPS1. UGATE1 swings between PHASE1 and BOOT1.

BOOT1 (Pin 22)

Boost Flying Capacitor Connection for SMPS1. Connect to an external capacitor according to the typical application circuits.

PGOOD (Pin 23)

Power Good Output for channel 1 and channel 2. (Logical AND)

VOUT1 (Pin 24)

SMPS1 Output Voltage-Sense Input. Connect to the SMPS1 output. VOUT1 is an input to the on-time oneshot circuit. It also serves as the SMPS1 feedback input in fixed-voltage mode.

Copyright ©2012 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

www.richtek.com

DS8205A/B/C-06 July 2012

8

 

 

RT8205A/B/C

Absolute Maximum Ratings (Note 1)

 

z VIN, EN to GND -----------------------------------------------------------------------------------------------

−0.3V to 28V

z PHASEx to GND

 

DC ----------------------------------------------------------------------------------------------------------------

−0.3V to 28V

< 20ns ----------------------------------------------------------------------------------------------------------

−8V

z BOOTx to PHASEx ------------------------------------------------------------------------------------------

−0.3V to 6V

z ENTRIPx, SKIPSEL, TONSEL, PGOOD, to GND ----------------------------------------------------

−0.3V to 6V

z VREG5, VREG3, FBx, VOUTx, SECFB, REF to GND ---------------------------------------------

−0.3V to (VREG5 + 0.3V)

z UGATEx to PHASEx

 

DC ----------------------------------------------------------------------------------------------------------------

−0.3V to (VREG5 + 0.3V)

< 20ns ----------------------------------------------------------------------------------------------------------

−5V

z LGATEx to GND

 

DC ----------------------------------------------------------------------------------------------------------------

−0.3V to (VREG5 + 0.3V)

< 20ns ----------------------------------------------------------------------------------------------------------

−2.5V

z Power Dissipation, PD @ TA = 25°C

 

WQFN-24L 4x4 -----------------------------------------------------------------------------------------------

1.923W

z Package Thermal Resistance (Note 2)

 

WQFN-24L 4x4, θJA ------------------------------------------------------------------------------------------

52°C/W

WQFN-24L 4x4, θJC -----------------------------------------------------------------------------------------

7°C/W

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

260°C

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

150°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 Input Voltage, VIN --------------------------------------------------------------------------------------------

6V to 25V

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

−40°C to 125°C

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

−40°C to 85°C

Copyright ©2012 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

DS8205A/B/C-06 July 2012

www.richtek.com

 

9

To be continued

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