Richtek RT8209AGQW, RT8209AZQW, RT8209BGQW, RT8209CGC Schematic [ru]

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®

RT8209A/B/C

Single Synchronous Buck Controller

General Description

The RT8209A/B/C PWM controller provides high efficiency, excellent transient response, and highDC output accuracy needed for stepping down high voltage batteries to generate low voltage CPU core, I/O, and chipset RAM supplies in notebook computers.

The constant-on-time PWM control scheme handles wide input/output voltage ratios with ease and provides 100ns “instant-on” response to load transients while maintaining a relatively constant switching frequency.

The RT8209A/B/C achieves high efficiency at a reduced cost by eliminating the current-sense resistor found in traditional current mode PWMs. Efficiency is further enhanced by its ability to drive very large synchronous rectifier MOSFETs. The buck conversion allows this device to directly step down high voltage batteries for the highest possible efficiency. The RT8209A/B/C is intended for CPU core, chipset, DRAM, or other low voltage supplies as low as 0.75V. The RT8209A is in a WQFN-16L 3x3 package, the RT8209B is in a WQFN-14L 3.5x3.5 package and the RT8209C is available in a TSSOP-14 package.

Ordering Information

RT8209

Package Type

QW : WQFN-16L 3x3 (W-Type) QW : WQFN-14L 3.5x3.5 (W-Type) C : TSSOP-14

Lead Plating System

G : Green (Halogen Free and Pb Free) Z : ECO (Ecological Element with

Halogen Free and Pb free)

A: WQFN-16L 3x3

B: WQFN-14L 3.5x3.5

C: TSSOP-14

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.

Features

zUltra-High Efficiency

zResistor Programmable Current Limit by Low Side RDS(ON) Sense (Lossless Limit)

zQuick Load Step Response within 100ns

z1% VFB Accuracy over Line and Load

z4.5V to 26V Battery Input Range

zResistor Programmable Frequency

zIntegrated Bootstrap Switch

zIntegrated Negative Current Limiter

zOver/Under Voltage Protection

z4 Steps Current Limit During Soft-Start

zPower Good Indicator

zRoHS Compliant and Halogen Free

Applications

zNotebook Computers

zSystem Power Supplies

zI/O Supplies

Marking Information

RT8209AGQW

FH= : Product Code

FH=YM YMDNN : Date Code

DNN

RT8209AZQW

FH : Product Code

FH YM YMDNN : Date Code

DNN

RT8209BGQW

A0= : Product Code

A0=YM YMDNN : Date Code

DNN

RT8209CGC

RT8209CGC : Product Code

RT8209C YMDNN : Date Code

GCYMDNN

Copyright ©2014 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

DS8209A/B/C-07 January 2014

www.richtek.com

 

1

RT8209A/B/C

Pin Configurations

 

TON

EN/DEM

NC

BOOT

 

 

16

15

14

13

 

VOUT

1

 

 

12

UGATE

VDD

2

NC

11

PHASE

FB

3

10

CS

 

 

PGOOD

 

 

17

VDDP

4

 

 

9

 

5

6

7

8

 

 

NC

GND

PGND

LGATE

 

RT8209A (WQFN-16L 3x3)

(TOP VIEW)

 

EN/DEM

BOOT

 

 

TON

1

14

 

UGATE

2

 

13

VOUT

3

 

12

PHASE

VDD

4

NC

11

CS

FB

5

15

10

VDDP

PGOOD

6

 

9

LGATE

 

7

8

 

 

 

GND

PGND

 

 

RT8209B (WQFN-14L 3.5x3.5)

EN/DEM

 

14

BOOT

TON

2

13

UGATE

VOUT

3

12

PHASE

VDD

4

11

CS

FB

5

10

VDDP

PGOOD

6

9

LGATE

GND

7

8

PGND

RT8209C (TSSOP-14)

Typical Application Circuit

 

 

 

 

 

 

 

 

 

 

 

R

 

 

 

 

 

 

 

 

 

 

 

TON

 

 

 

V

 

 

 

 

 

 

250k

 

 

 

 

 

 

 

 

 

 

 

 

IN

 

 

 

 

 

 

 

 

 

 

4.5V to 26V

 

 

 

 

 

 

RT8209A/B/C

R4

 

 

 

C4

 

 

 

 

 

0

 

 

 

 

 

 

 

 

TON

BOOT

 

 

 

10µF

 

 

 

 

 

 

C3

 

 

 

 

 

VDDP

 

VDDP

 

R5

 

Q1

 

 

 

 

 

 

0

0.1µF

 

 

 

VOUT = 1.05V

 

R1

 

UGATE

 

BSC119 L1

 

 

 

 

 

 

 

 

 

 

 

 

 

N03S

1µH

* : Optional

 

R2

10

 

PHASE

 

 

 

 

VDD

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

100k

C2

 

BSC119N03S

 

 

 

 

 

 

 

 

 

 

 

C1

 

LGATE

 

Q2

R7*

C5*

C6*

 

1µF

 

 

 

 

 

 

 

 

 

 

 

 

220µF

 

 

 

 

 

 

 

 

 

R8

 

PGOOD

 

PGOOD

PGND

 

 

 

 

C7*

12k

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CS

FB

 

 

 

 

 

 

 

 

 

R6

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R9

 

 

 

18k

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

30k

 

 

 

 

 

 

 

 

 

 

 

 

 

CCM/DEM

EN/DEM

VOUT

 

 

 

 

 

 

 

 

 

 

GND

 

 

 

 

 

 

 

 

Functional Pin Description

Pin No.

Pin Name

Pin Function

 

 

RT8209A

RT8209B/C

 

 

 

 

 

 

1

3

VOUT

Output Voltage Pin. Connect to the output of PWM converter.

VOUT is an input of the PWM controller.

 

 

 

2

4

VDD

Analog supply voltage input for the internal analog integrated

circuit. Bypass to GND with a 1μF ceramic capacitor.

 

 

 

3

5

FB

Feedback Input Pin. Connect FB to a resistor voltage divider

from VOUT to GND to adjust VOUT from 0.75V to 3.3V

 

 

 

 

 

 

Power good signal open-drain output of PWM converter. This

4

6

PGOOD

pin will be pulled high when the output voltage is within the

 

 

 

target range.

5, 14

RT8209B :

 

No internal connection. The exposed pad must be soldered to

NC

a large PCB and connected to GND for maximum power

17 (Exposed pad)

15 (Exposed pad)

 

 

 

dissipation.

 

 

 

 

Copyright ©2014 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

www.richtek.com

 

 

DS8209A/B/C-07 January 2014

2

Richtek RT8209AGQW, RT8209AZQW, RT8209BGQW, RT8209CGC Schematic

 

 

 

 

RT8209A/B/C

 

 

 

 

 

 

Pin No.

Pin Name

Pin Function

 

 

 

RT8209A

 

RT8209B/C

 

 

 

 

 

 

 

 

6

 

7

GND

Analog Ground.

 

 

 

 

 

7

 

8

PGND

Power Ground.

 

 

 

 

 

8

 

9

LGATE

Low side N-MOSFET gate driver output for PWM. This pin

 

swings between GND and VDDP.

 

 

 

 

9

 

10

VDDP

VDDP is the gate driver supply for external MOSFETs. Bypass

 

to GND with a 1μF ceramic capacitor.

 

 

 

 

 

 

 

 

Over Current Trip Point Set Input. Connect resistor from this

10

 

11

CS

pin to signal ground to set threshold for both over current and

 

 

 

 

negative over current limit.

11

 

12

PHASE

The UGATE High Side Gate Driver Return. Also serves as

 

anode of over current comparator.

 

 

 

 

12

 

13

UGATE

High side N-MOSFET floating gate driver output for the PWM

 

converter. This pin swings between PHASE and BOOT.

 

 

 

 

13

 

14

BOOT

Bootstrap Capacitor Connection for PWM Converter. Connect

 

to an external ceramic capacitor to PHASE.

 

 

 

 

 

 

 

 

Enable/Diode Emulation Mode Control Input. Connect to VDD

15

 

1

EN/DEM

for diode-emulation mode, connect to GND for shutdown and

 

 

 

 

floating the pin for CCM mode.

16

 

2

TON

On Time/Frequency Adjustment Pin. Connect to PHASE

 

through a resistor. TON is an input for the PWM controller.

 

 

 

 

Function Block Diagram

 

 

 

 

 

 

 

 

 

TRIG

 

 

 

 

 

 

 

VOUT

 

 

On-time

 

 

 

 

 

 

 

 

Compute

 

 

 

 

 

 

BOOT

TON

 

 

 

 

 

 

 

 

 

1-SHOT

 

 

 

R

 

 

 

 

 

 

 

 

 

 

 

 

SS

 

+

 

 

 

 

 

 

 

-

 

 

-

 

 

 

 

 

(internal)

GM

 

 

+

 

S

Q

DRV

UGATE

 

+

-

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Min. TOFF

 

 

PHASE

VREF

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Q

TRIG

 

 

VDDP

 

 

 

 

Latch

 

1-SHOT

 

 

 

 

+

OV

 

 

 

 

125% VREF

S1

Q

 

 

 

DRV

LGATE

-

 

Latch

 

 

 

70% VREF

+

UV

 

 

 

 

PGND

S1

Q

 

 

 

 

FB

 

 

 

 

 

PGOOD

 

-

 

 

-

 

 

 

 

 

 

 

 

 

 

Diode

 

 

 

 

 

 

90% VREF

+

 

Emulation

 

 

10µA

VDD

 

SS Timer

Thermal

 

 

+

+

CS

 

 

 

 

Shutdown

 

 

GM

GND

EN/DEM

 

 

 

 

 

 

 

-

-

 

 

 

 

 

 

 

 

 

Copyright ©2014 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

DS8209A/B/C-07 January 2014

www.richtek.com

3

RT8209A/B/C

Absolute Maximum Ratings (Note 1)

z VDD, VDDP, VOUT, EN/DEM, FB, PGOOD, TON to GND-------------------------------------------------------

−0.3V to 6V

z BOOT to GND --------------------------------------------------------------------------------------------------------------

0.3V to 38V

z BOOT to PHASE ----------------------------------------------------------------------------------------------------------

−0.3V to 6V

z PHASE to GND

 

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

–0.3V to 32V

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

−8V to 38V

z UGATE to PHASE

 

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

−0.3V to 6V

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

−5V to 7.5V

z CS to GND ------------------------------------------------------------------------------------------------------------------

−0.3V to 6V

z LGATE to GND -------------------------------------------------------------------------------------------------------------

−0.3V to 6V

z LGATE to GND

 

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

−0.3V to 6V

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

−2.5V to 7.5V

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

–0.3V to 0.3V

z Power Dissipation, PD @ TA = 25°C

 

WQFN−16L 3x3 ------------------------------------------------------------------------------------------------------------

1.471W

WQFN−14L 3.5x3.5 -------------------------------------------------------------------------------------------------------

1.667W

TSSOP-14-------------------------------------------------------------------------------------------------------------------

0.741W

z Package Thermal Resistance (Note 2)

 

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

68°C/W

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

7.5°C/W

WQFN−14L 3.5x3.5, θJA -------------------------------------------------------------------------------------------------

60°C/W

WQFN−14L 3.5x3.5, θJC -------------------------------------------------------------------------------------------------

7.5°C/W

TSSOP-14, θJA -------------------------------------------------------------------------------------------------------------

135°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 Mode) ----------------------------------------------------------------------------------------------

2kV

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

200V

Recommended Operating Conditions

(Note 4)

z Input Voltage, VIN ----------------------------------------------------------------------------------------------------------

4.5V to 26V

z Supply Voltage, VDD, VDDP ----------------------------------------------------------------------------------------------

4.5V to 5.5V

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

−40°C to 125°C

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

−40°C to 85°C

Copyright ©2014 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

www.richtek.com

DS8209A/B/C-07 January 2014

4

RT8209A/B/C

Electrical Characteristics

(VIN = 15V, VDD = VDDP = 5V, TA = 25°C, unless otherwise specified)

Parameter

 

Symbol

Test Conditions

Min

Typ

Max

 

Unit

PWM Controller

 

 

 

 

 

 

 

 

 

Quiescent Supply Current

IVDD

VFB = 0.8V, EN/DEM = 5V

--

500

800

 

μA

IVDDP

VFB = 0.8V, EN/DEM = 5V

--

1

10

 

 

 

 

 

Shutdown Current

 

ISHDN_VDD

EN/DEM = 0V

 

--

1

10

 

μA

 

 

 

 

 

 

 

 

 

ISHDN_VDDP

EN/DEM = 0V

 

--

--

1

 

 

 

 

 

 

FB Reference Voltage

 

VREF

VDD = 4.5V to 5.5V

0.742

0.750

0.758

 

V

FB Input Bias Current

 

 

VFB = 0.75V

 

−1

0.1

1

 

μA

Output Voltage Range

 

VOUT

 

 

0.75

--

3.3

 

V

On Time

 

 

VPHASE = 12V, VOUT = 2.5V,

336

420

504

 

ns

 

 

 

RTON = 250kΩ

 

 

 

 

 

 

Minimum Off-Time

 

 

 

 

250

400

550

 

ns

VOUT Shutdown Discharge

 

EN/DEM = GND

 

--

20

--

 

Ω

Resistance

 

 

 

 

 

 

 

 

 

 

 

 

 

Current Sensing

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Current Limiter Source Current

 

CS to GND

 

9

10

11

 

μA

 

 

 

 

 

 

 

 

 

Current Comparator Offset

 

 

 

−10

--

10

 

mV

Zero Crossing Threshold

 

 

PHASE to GND, EN/DEM = 5V

−10

--

5

 

mV

Fault Protection

 

 

 

 

 

 

 

 

 

Current Limit Threshold

 

 

GND − PHASE, VCS = 50mV

40

50

60

 

mV

 

 

GND − PHASE, VCS = 200mV

190

200

210

 

 

 

 

 

 

Current Limit Setting Range

 

CS to GND

 

50

--

200

 

mV

Output UV Threshold

 

 

UVP detect

 

60

70

80

 

%

OVP Threshold

 

VFB_OVP

OVP detect

 

120

125

130

 

%

OV Fault Delay

 

 

FB forced above OV threshold

--

20

--

 

μs

VDD Under Voltage Lockout

 

Rising edge, PWM disabled below

4.1

4.3

4.5

 

V

 

this level

 

 

Threshold

 

 

 

 

 

 

 

 

 

 

Hysteresis

 

--

80

--

 

mV

 

 

 

 

 

Current Limit Step Duration at

 

Each step

 

--

128

--

 

clks

Soft-Start

 

 

 

 

 

 

 

 

 

 

 

 

 

UVP Blanking Time

 

 

From EN signal going high

--

512

--

 

clks

Thermal Shutdown

 

TSHDN

Hysteresis = 10°C

--

155

--

 

°C

Driver On-Resistance

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

UGATE Drive Source

 

RUGATEsr

VBOOT − VPHASE = 5V

--

2

5

 

Ω

UGATE Drive Sink

 

RUGATEsk

VBOOT − VPHASE = 5V

--

1

5

 

Ω

LGATE Drive Source

 

RLGATEsr

LGATE, High State

--

1

5

 

Ω

LGATE Drive Sink

 

RLGATEsk

LGATE, Low State

--

0.5

2.5

 

Ω

UGATE Driver Source/Sink

 

VUGATE − VPHASE = 2.5V,

--

1

--

 

A

Current

 

 

VBOOT − VPHASE = 5V

 

 

 

 

 

LGATE Driver Source Current

 

VLGATE = 2.5V

 

--

1

--

 

A

LGATE Driver Sink Current

 

VLGATE = 2.5V

 

--

3

--

 

A

Dead Time

 

 

LGATE Rising (VPHASE = 1.5V)

--

30

--

 

ns

 

 

UGATE Rising

 

--

30

--

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Copyright ©2014 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

 

DS8209A/B/C-07 January

2014

 

 

 

 

 

www.richtek.com

5

RT8209A/B/C

Parameter

Symbol

Test Conditions

Min

Typ

Max

Unit

Internal BOOT Charging Switch

 

VDDP to BOOT, 10mA

--

--

80

Ω

On Resistance

 

 

 

 

 

 

 

Logic I/O

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EN/DEM Low

--

--

0.8

 

EN/DEM Logic Input Voltage

 

EN/DEM High

2.9

--

--

V

 

 

 

 

 

 

 

 

 

EN/DEM float

--

2

--

 

 

 

 

 

 

 

 

Logic Input Current

 

EN/DEM = VDD

--

1

5

μA

 

EN/DEM = 0

−5

1

--

 

 

 

PGOOD

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VFB with respect to reference,

87

90

93

 

 

 

PGOOD from Low to High

 

 

 

 

 

 

 

PGOOD Threshold

 

VFB with respect to reference,

--

125

--

%

 

 

PGOOD from High to Low

 

 

 

 

 

 

 

 

 

Hysteresis

--

3

--

 

Fault Propagation Delay

 

Falling edge, FB forced below

--

2.5

--

μs

 

PGOOD trip threshold

 

 

 

 

 

 

Output Low Voltage

 

ISINK = 1mA

--

--

0.4

V

Leakage Current

 

High state, forced to 5V

--

--

1

μA

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 expose pad for 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.

Copyright ©2014 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

www.richtek.com

DS8209A/B/C-07 January 2014

6

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