Richtek RT8206AGQW, RT8206BGQW Schematic [ru]

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RT8206A/B

High-Efficiency, Main Power Supply Controllers for Notebook Computers

General Description

The RT8206A/B dual step-down, switch-mode powersupply (SMPS) controller generates logic-supply voltages in battery-powered systems. The RT8206A/B includes two pulse-width modulation (PWM) controllers fixed at 5V/ 3.3V or adjustable from 2V to 5.5V. An optional external charge pump can be monitored through SECFB (RT8206A). This device also features a linear regulator providing a fixed 5V output. The linear regulator provides up to 70mA output current with automatic linear-regulator bootstrapping to the BYP input. The RT8206A/B includes on-board power-up sequencing, the power-good outputs, internal soft-start, and internal soft-discharge output that prevents negative voltages on shutdown.

A constant on-time PWM control scheme operates without sense resistors 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.

The RT8206A/B is available in the WQFN-32L 5x5 package.

Features

zWide Input Voltage Range 6V to 25V

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

zSecondary Feedback Input Maintains Charge Pump Voltage (RT8206A)

zIndependent Enable and Power Good

z5V Fixed LDO Output : 70mA

z2V Reference Voltage ±1% : 50uA

zConstant ON-Time Control with 100ns Load Step Response

zFrequency Selectable via TON Setting

zRDS(ON) Current Sensing and Programmable Current Limit

zSelectable PWM, DEM or Ultrasonic Mode

zInternal Soft-Start with 5 Steps Current Limiting 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

RT8206

Package Type

QW : WQFN-32L 5x5 (W-Type)

Lead Plating System

G : Green (Halogen Free and Pb Free)

A : With SECFB

B : Without 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.

Marking Information

RT8206AGQW

RT8206AGQW : Product Number

RT8206A YMDNN : Date Code

GQW

YMDNN

RT8206BGQW

RT8206BGQW : Product Number

RT8206B YMDNN : Date Code

GQW YMDNN

DS8206A/B-05 May 2011

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1

RT8206A/B

Pin Configurations

 

 

 

(TOP VIEW)

FB2 ILIM2 VOUT2

 

SKIP PGOOD2 EN2 UGATE2 PHASE2

FB2 ILIM2 VOUT2

 

SKIP PGOOD2 EN2 UGATE2 PHASE2

 

 

 

32

31

30

29

28

27

26

25

 

 

REF

1

 

 

 

 

 

 

24

BOOT2

REF

TON

2

 

 

 

 

 

 

23

LGATE2

TON

VCC

3

 

 

 

 

 

 

22

PGND

VCC

ENLDO

4

 

 

GND

 

 

21

GND

ENLDO

NC

5

 

 

 

 

20

SECFB

NC

 

 

 

 

 

 

VIN

6

 

 

 

 

 

 

19

PVCC

VIN

LDO

7

 

 

 

 

 

33

18

LGATE1

LDO

NC

8

 

 

 

 

 

 

17

BOOT1

NC

 

9

10

11

12

13

14

15

16

 

 

32

31

30

29

28

27

26

25

 

1

 

 

 

 

 

 

24

BOOT2

2

 

 

 

 

 

 

23

LGATE2

3

 

 

 

 

 

 

22

PGND

4

 

 

GND

 

 

21

GND

5

 

 

 

 

20

NC

 

 

 

 

 

 

6

 

 

 

 

 

 

19

PVCC

7

 

 

 

 

 

33

18

LGATE1

8

 

 

 

 

 

 

17

BOOT1

9

10

11

12

13

14

15

16

 

BYP VOUT1 FB1 ILIM1 PGOOD1 EN1 UGATE1 PHASE1

BYP VOUT1 FB1 ILIM1 PGOOD1 EN1 UGATE1 PHASE1

WQFN-32L 5x5

WQFN-32L 5x5

RT8206A

RT8206B

Typical Application Circuit

VOUT1

5V

C3 220µF

 

 

 

 

 

 

 

 

 

 

 

 

 

 

V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

IN

 

C1

 

 

R14

 

RT8206A/B

 

R9

 

C13

6V to 25V

 

 

 

 

 

 

C12

 

 

 

3.9

 

 

 

 

10µF

 

 

 

 

6

VIN

UGATE2 26

 

0

Q2

10µF

10µF

 

 

 

 

C18

 

 

 

 

 

 

 

 

 

 

 

R8

0

 

 

 

 

 

 

 

0.1µF

 

BOOT2 24

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R4

0

 

 

 

 

 

C11

 

L2

 

 

 

Q1

15 UGATE1

PHASE2 25

 

0.1µF

 

4.7µH

VOUT2

 

 

 

 

 

 

 

 

 

 

 

 

R3

0

17 BOOT1

LGATE2 23

 

 

Q4

 

3.3V

 

 

 

 

 

 

R10

C17

 

 

 

 

 

 

 

 

 

L1

 

 

C2

 

 

 

PGND 22

 

 

 

 

220µF

 

 

 

 

 

 

 

 

 

C14

 

6.8µH

 

 

0.1µF

 

16 PHASE1

 

 

 

 

 

 

 

 

 

 

 

 

 

VOUT2 30

 

 

 

 

 

 

 

Q3

 

 

18 LGATE1

 

 

 

 

 

 

R5

 

 

REF 1

 

C15

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R6

 

 

 

C4

 

 

 

 

9 BYP

 

 

 

0.22µF

 

 

 

 

 

 

 

PGOOD1

13

 

 

100k

PV

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

10

VOUT1

 

 

 

R13

CC

 

 

 

 

 

C5

 

 

 

 

 

 

 

 

 

D1

 

 

 

 

PGOOD2 28

 

 

100k

PVCC

 

C6

 

 

0.1µF

 

 

 

 

 

 

 

D2

 

 

 

 

3 VCC

EN1 14

5V Enable

 

ON

 

0.1µF

 

 

 

 

 

 

 

 

 

 

C7

 

C9

 

EN2 27

3.3V Enable

 

OFF

 

 

 

D3

 

0.1µF

 

1µF

 

 

 

C8

D4

 

 

 

 

 

 

ENLDO 4

LDO Control

 

VIN

 

 

 

 

 

 

 

 

 

 

 

0.1µF

 

 

 

 

 

 

 

 

 

 

R1

 

 

 

 

R11

 

 

 

 

 

ILIM1 12

 

180k

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

200k

 

 

 

20 SECFB/NC

 

 

 

R2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R12

 

11

FB1

ILIM2

31

 

180k

 

 

 

 

 

 

 

39k

 

 

 

 

 

 

 

 

CP

C19

 

 

 

32 FB2

TON 2

 

Frequency Control

 

 

 

 

R7

0

 

19

 

SKIP

29

 

PWM/DEM/Ultrasonic

 

 

 

 

 

PVCC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C16

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

GND 21, Exposed Pad (33)

 

 

 

 

 

 

 

1µF

 

7 LDO

 

 

 

 

 

C10

 

 

 

 

 

 

 

 

 

 

 

 

4.7µF

 

 

 

 

 

 

 

 

 

 

Figure 1. Fixed Voltage Regulator

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DS8206A/B-05 May 2011

2

 

RT8206A/B

VOUT1

5V

C3 220µF

C23

C20 0.1µF

C1

 

 

 

 

 

 

R14

 

RT8206A/B

 

 

3.9

 

10µF

 

 

 

 

 

 

 

 

 

 

 

 

6

VIN

UGATE2 26

 

 

 

 

 

 

 

 

 

 

 

C18

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0.1µF

 

BOOT2 24

 

Q1

R4 0

15

UGATE1

 

 

 

 

 

R3

0

17

BOOT1

 

 

 

 

L1

 

C2

 

 

 

6.8µH

 

0.1µF

 

16

PHASE1

 

 

 

 

R5

Q3

 

 

18

LGATE1

C6 0.1µF

C8 0.1µF

C4

 

D1

C5

0.1µF

 

D2

 

D3

C7

0.1µF

 

D4

 

 

R11

 

200k

9 BYP

10 VOUT1

3 VCC C9 1µF

20 SECFB/NC

R12

PHASE2 25

LGATE2 23 PGND 22

VOUT2 30 FB2 32

REF 1

PGOOD1 13

PGOOD2 28

EN1 14

EN2 27 ENLDO 4

ILIM1 12

R9

 

 

0

Q2

 

 

R8

0

 

 

 

C11

 

 

0.1µF

 

 

Q4

C15

R6

0.22µF

 

100k

 

R13

 

100k

5V Enable

 

3.3V Enable

 

LDO Control

 

 

R1

 

180k

 

 

 

V

 

 

 

IN

C13

 

 

6V to 25V

C12

 

 

10µF

 

 

10µF

 

 

 

 

 

L2

 

 

V

4.7µH

 

 

 

 

 

OUT2

 

 

C17

3.3V

R10

 

 

 

220µF

C14

 

 

 

 

R17

 

C22

 

11.5k

 

 

 

 

 

R18

 

C21

 

 

0.1µF

 

10k

 

 

PV

 

 

 

CC

 

 

 

PV

 

 

 

CC

 

 

 

ON

 

 

 

OFF

 

 

 

V

 

 

 

IN

 

 

 

R15 15k

R16 10k

CP

39k

C19

 

R7

0

 

C16

 

1µF

C10

 

4.7µF

11 FB1

19 PVCC

7 LDO

 

 

R2

ILIM2 31

180k

 

TON

2

Frequency Control

SKIP

29

PWM/DEM/Ultrasonic

 

 

 

GND 21, Exposed Pad (33)

Figure 2. Adjustable Voltage Regulator

DS8206A/B-05 May 2011

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3

Richtek RT8206AGQW, RT8206BGQW Schematic

RT8206A/B

Function Block Diagram

 

 

TON

SKIP

 

BOOT1

 

 

 

BOOT2

UGATE1

 

 

 

UGATE2

PHASE1

PVCC

 

 

PHASE2

 

 

 

PVCC

LGATE1

 

SMPS1

SMPS2

LGATE2

 

PWM Buck

PWM Buck

 

 

 

PGND

 

Controller

Controller

 

VOUT1

 

 

 

VOUT2

FB1

 

 

 

FB2

ILIM1

 

 

 

ILIM2

PGOOD1

 

 

 

PGOOD2

GND

SW Threshold

 

 

 

 

VCC

BYP

 

 

 

 

Internal

 

PVCC

 

 

Power-On

 

 

ENLDO

 

 

Logic

 

 

Sequence

 

 

EN1

 

 

 

 

 

 

Clear Fault Latch

 

 

 

EN2

 

 

 

 

LDO

 

Thermal

 

 

 

LDO

REF

REF

 

Shutdown

 

 

 

 

VIN

 

 

 

 

Function Block Diagram

 

 

TON

VIN

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

UGATE

VOUT

 

On-Time

TON

 

Q

R

TRIG

TOFF

 

 

Compute

1-Shot

1-Shot

 

 

 

 

 

 

Q

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TRIG

 

 

 

 

 

 

 

 

 

 

 

 

REF

-

+

-

Comp

 

 

 

 

 

+

-

+

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

LGATE

FB

 

 

Over-Voltage

 

Fault

 

 

 

VCC

1.1 x VREF

+

 

 

 

 

 

 

 

-

 

 

Latch

 

 

 

 

 

0.7 x VREF

-

 

 

Blanking

 

+

ILIM

 

+

 

 

Time

 

 

 

 

 

 

 

-

 

 

 

 

Under-Voltage

 

 

 

 

 

 

 

-

 

 

 

 

 

Current

 

 

 

 

 

 

 

 

 

Limit

 

 

0.9 x VREF

 

 

 

 

SS

 

 

+

 

 

 

+

 

 

 

 

 

 

 

 

Time

-

 

PGOOD

 

 

 

 

 

 

25kHz

 

+

PHASE

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Detector

Zero

-

 

 

 

 

 

 

 

 

 

Detector

 

 

 

 

 

 

 

 

 

 

SKIP

 

PWM Controller (One Side)

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DS8206A/B-05 May 2011

4

RT8206A/B

Functional Pin Description

REF (Pin 1)

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.

TON (Pin 2)

Frequency Select Input. (VOUT1/VOUT2 switching frequency, respectively) :

TON = VCC, (200kHz / 250kHz)

TON = REF, (300kHz / 375kHz)

TON = GND, (400kHz / 500kHz)

VCC (Pin 3)

Analog Supply Voltage Input for the PWM Core. Bypass to GND with a 1uF ceramic capacitor

ENLDO (Pin 4)

LDO Enable Input. The REF/LDO is enabled if ENLDO is within logic high level and disable if ENLDO is less than the logic low level.

NC (Pin 5, 8)

No Internal Connection.

VIN (Pin 6)

Power-supply Input. VIN is used for the constant on-time PWM one shot circuits. VIN is also used to power the linear regulators. The linear regulators are powered by SMPS1 if VOUT1 is set greater than 4.66V and BYP is tied to VOUT1. Connect VIN to the battery input and bypass with a 1uF capacitor.

LDO (Pin 7)

Linear-Regulator Output. LDO can provide a total of 70mA external loads. The LDO regulates a fixed 5V output. When the BYP is within 5V switchover threshold, the internal regulator shuts down and the LDO output pin connects to BYP through a 1.5Ω switch. Bypass LDO output with a minimum of 4.7uF ceramic.

BYP (Pin 9)

BYP is the switchover source voltage input for the LDO.

VOUT1 (Pin 10)

SMPS1 Output Voltage-Sense Input. Connect this pin to the SMPS1 output. VOUT1 is an input to the Constant on-time-PWM one-shot circuit. It also serves as the SMPS1 feedback input in fixed-voltage mode.

FB1 (Pin 11)

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

ILIM1 (Pin 12)

SMPS1 Current-Limit Adjustment. The GND − PHASE1 current-limit threshold is 1/10th the voltage seen at ILIM1 over a 0.5V to 2V range. There is an internal 5uA current source from VCC to ILIM1. The logic current limit threshold is default to 100mV if ILIM1 is higher than (VCC − 1V).

PGOOD1 (Pin 13)

SMPS1 Power-Good Open-Drain Output. PGOOD1 is low when the SMPS1 output voltage is more than 7.5% below the normal regulation point or during soft-start. PGOOD1 is high impedance when the output is in regulation and the soft-start circuit has terminated. PGOOD1 is low in shutdown.

EN1 (Pin 14)

SMPS1 Enable Input. The SMPS1 will be enabled if EN1 is greater than the logic high level and disabled if EN1 is less than the logic low level. If EN1 is connected to REF, the SMPS1 starts after the SMPS2 reaches regulation (delay start). Drive EN1 below 0.8V to clear fault level and reset the fault latches.

UGATE1 (Pin 15)

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

PHASE1 (Pin 16)

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

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5

RT8206A/B

BOOT1 (Pin 17)

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

LGATE1 (Pin 18)

SMPS1 Synchronous-RectifierGate-drive Output. LGATE1 swings between PGND and PVCC.

PVCC (Pin 19)

PVCC is the supply voltage for the low-side MOSFET driver LGATEx. Connect a 5V power source to the PVCC pin (bypass with 1uF MLCC capacitor to PGND if necessary). There is an internal 10Ω connecting from PVCC to VCC. Make sure that both VCC and PVCC are bypassed with 1uF MLCC capacitors.

SECFB (Pin 20) (RT8206A)

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

PHASE2 (Pin 25)

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

UGATE2 (Pin 26)

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

EN2 (Pin 27)

SMPS2 Enable Input. The SMPS2 will be enabled if EN2 is greater than the logic high level and be disabled if EN2 is less than the logic low level. If EN2 is connected to REF, the SMPS2 starts after the SMPS1 reaches regulation (delay start). Drive EN2 below 0.8V to clear fault level and reset the fault latches.

PGOOD2 (Pin 28)

SMPS2 Power-Good Open-Drain Output. PGOOD2 is low when the SMPS2 output voltage is more than 7.5% below the normal regulation point or during soft-start. PGOOD2 is high impedance when the output is in regulation and the soft-start circuit has terminated. PGOOD2 is low in shutdown.

SKIP (Pin 29)

NC (Pin 20) (RT8206B)

No Internal Connection.

GND [Pin 21, Exposed Pad (33)]

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

PGND (Pin 22)

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

LGATE2 (Pin 23)

SMPS2 Synchronous-RectifierGate-drive Output. LGATE2 swings between PGND and PVCC.

BOOT2 (Pin 24)

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

SMPS Operation Mode Control.

SKIP = GND : DEM operation

SKIP = REF : Ultrasonic Mode operation

SKIP = VCC : PWM operation.

VOUT2 (Pin 30)

SMPS2 Output Voltage-Sense Input. Connect this pin to the SMPS2 output. VOUT2 is an input to the constant on-time-PWM one-shot circuit. It also serves as the SMPS2 feedback input in fixed-voltage mode.

ILIM2 (Pin 31)

SMPS2 Current-Limit Adjustment. The GND − PHASE2 current-limit threshold is 1/10th the voltage seen at ILIM2 over a 0.5V to 2V range. There is an internal 5uA current source from VCC to ILIM2. The logic current limit threshold is default to 100mV value if ILIM2 is higher than (VCC − 1V).

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DS8206A/B-05 May 2011

6

 

RT8206A/B

FB2 (Pin 32)

SMPS2 Feedback Input. Connect FB2 to VCC or GND for fixed 3.3V operation. Connect FB2 to a resistive voltagedivider from VOUT2 to GND to adjust output from 2V to 5.5V.

DS8206A/B-05 May 2011

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7

RT8206A/B

Absolute Maximum Ratings (Note 1)

z VIN, ENLDO to GND ----------------------------------------------------------------------------------------------

–0.3V to 30V

z PHASEx to GND

 

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

–0.3V to 30V

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

–8V to 38V

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

–0.3V to 6V

z VCC, ENx, SKIP, TON, PVCC, PGOODx, to GND -------------------------------------------------------

–0.3V to 6V

z LDO, FBx,

 

 

–0.3V to (VCC + 0.3V)

VOUTx, SECFB, REF, ILIMx to GND ----------------------------------------------------------

z UGATEx to PHASEx

 

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

–0.3V to (PVCC + 0.3V)

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

–5V to 7.5V

z LGATEx, BYP to GND

 

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

–0.3V to (PVCC + 0.3V)

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

–2.5V to 7.5V

z PGND to GND ------------------------------------------------------------------------------------------------------

–0.3V to 0.3V

z Power Dissipation, PD @ TA = 25°C

 

WQFN-32L 5x5 ----------------------------------------------------------------------------------------------------

2.778W

z Package Thermal Resistance (Note 2)

 

WQFN-32L 5x5, θJA -----------------------------------------------------------------------------------------------

36°C/W

WQFN-32L 5x5, θJC ----------------------------------------------------------------------------------------------

7°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 Mode) --------------------------------------------------------------------------------------

2kV

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

200V

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

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DS8206A/B-05 May 2011

8

 

 

To be continued

RT8206A/B

Electrical Characteristics

(VIN = 12V, EN1 = EN2 = VCC, VBYP = 5V, PVCC = 5V, VENLDO = 5V, No Load on LDO, VOUT1, VOUT2 and REF, TA = 25°C, unless otherwise specified)

 

Parameter

Symbol

 

 

 

 

Test Conditions

 

Min

 

Typ

 

Max

Unit

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Input Supply

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VIN Standby Supply Current

IVIN_SBY

VIN = 6V to 25V, Both SMPS Off,

--

180

250

μA

 

 

ENLDO = 5V

 

 

 

 

 

 

 

 

 

 

 

 

 

VIN Shutdown Supply

IVIN_SHDH

VIN = 6V to 25V,

--

20

40

μA

 

 

Current

ENx = ENLDO = GND

 

 

 

 

Both SMPSs On,

 

 

 

 

 

 

 

 

 

Quiescent Power

 

FB1 =

SKIP

= GND, FB2 = VCC,

--

5

7

mW

 

 

Consumption

 

VOUT1 = BYP = 5.3V,

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VOUT2 = 3.5V (Note 5)

 

 

 

 

 

 

 

 

 

SMPS Output and FB Voltage

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VOUT1 Output Voltage in

VOUT1

 

VIN = 6V to 25V, FB1= GND,

 

4.975

 

5.05

 

5.125

V

 

 

Fixed Mode

 

SKIP

= 5V

 

 

 

 

 

 

 

 

 

 

 

VOUT2 Output Voltage in

VOUT2

 

VIN = 6V to 25V, FB2 = VCC,

 

3.285

 

3.33

 

3.375

V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Fixed Mode

 

SKIP = 5V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

FBx in Output Adjustable

FBx

 

VIN = 6V to 25V

 

1.975

 

2

 

2.025

V

 

 

Mode

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SECFB Voltage

SECFB

 

VIN = 6V to 25V (RT8206A)

 

1.92

 

2

 

2.08

V

 

 

Output Voltage Adjust

 

 

SMPS1, SMPS2

 

2

 

--

 

5.5

V

 

 

Range

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

FBx Adjustable-mode

 

 

Fixed or Adj-Mode comparator

 

0.2

 

0.4

 

0.55

V

 

 

Threshold Voltage

 

 

threshold

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Either SMPS,

 

= VCC, 0 to 5A

 

--

 

−0.1

 

--

 

 

 

 

 

SKIP

 

 

 

DC Load Regulation

VLOAD

 

Either SMPS,

 

 

 

= REF, 0 to 5A

 

--

 

−1.7

 

--

%

 

SKIP

 

 

 

 

Either SMPS,

 

 

 

= GND, 0 to 5A

 

--

 

−1.5

 

--

 

 

 

 

 

SKIP

 

 

 

Line Regulation

VLINE

 

Either SMPS, VIN = 6V to 25V

 

--

 

0.005

 

--

%/V

 

 

On Time

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TON =

 

SMPS1 = 5.05V (200kHz)

 

1895

 

2105

 

2315

 

 

 

 

 

 

VCC

 

SMPS2 = 3.33V (250kHz)

 

999

 

1110

 

1221

 

 

 

On-Time Pulse Width

tUGATEx

 

TON =

 

SMPS1 = 5.05V (300kHz)

 

1227

 

1403

 

1579

ns

 

 

 

REF

 

SMPS2 = 3.33V (375kHz)

 

647

 

740

 

833

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TON =

 

SMPS1 = 5.05V (400kHz)

 

895

 

1052

 

1209

 

 

 

 

 

 

GND

 

SMPS2 = 3.33V (500kHz)

 

475

 

555

 

635

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Minimum Off-Time

tLGATEx

 

 

 

 

 

 

 

 

 

 

 

200

 

300

 

400

ns

 

 

Ultrasonic Mode Frequency

 

 

 

= REF

 

25

 

33

 

--

kHz

 

 

 

 

SKIP

 

 

 

 

 

Soft Start

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Soft-Start Time

tSSx

 

Zero to full limit from ENx Enable

 

--

 

2

 

--

ms

 

 

Current Sense

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Current Limit Threshold

 

 

ILIMx = VCC, GND − PHASEx

 

90

 

100

 

110

mV

 

 

(Default)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Current Limit Current

ILIMX

 

 

 

 

 

 

 

 

 

 

 

4.75

 

5

 

5.25

μA

 

 

Source

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

To be continued

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DS8206A/B-05 May 2011

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

www.richtek.com

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

9

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