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

®

Single Synchronous Buck Controller

RT8209A/B/C

General Description

The RT8209A/B/C PWM controller provides high efficiency,

excellent transient response, and high DC 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 require-

ments of IPC/JEDEC J-STD-020.

` Suitable for use in SnPb or Pb-free soldering processes.

Features

zz

Ultra-High Efficiency

z

zz

zz

z Resistor Programmable Current Limit by Low Side

zz

R

zz

z Quick Load Step Response within 100ns

zz

zz

z 1% V

zz

zz

z 4.5V to 26V Battery Input Range

zz

zz

z Resistor Programmable Frequency

zz

zz

z Integrated Bootstrap Switch

zz

zz

z Integrated Negative Current Limiter

zz

zz

z Over/Under Voltage Protection

zz

zz

z 4 Steps Current Limit During Soft-Start

zz

zz

z Power Good Indicator

zz

zz

z RoHS Compliant and Halogen Free

zz

Sense (Lossless Limit)

DS(ON)

Accuracy over Line and Load

FB

Applications

z Notebook Computers

z System Power Supplies

z I/O Supplies

Marking Information

RT8209AGQW

FH= : Product Code

FH=YM

DNN

RT8209AZQW

FH YM

DNN

RT8209BGQW

A0=YM

DNN

RT8209CGC

RT8209C
GCYMDNN

YMDNN : Date Code

FH : Product Code

YMDNN : Date Code

A0= : Product Code

YMDNN : Date Code

RT8209CGC : Product Code

YMDNN : Date Code

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

BOOT

NC

13141516

NC

GND

12

UGATE

11

PHASE

10

CS

17

9

VDDP

8765

PGND

LGATE

R

2

RT8209A/B/C

T

O

N

V

D

D

P

1

R

1

0

2

R

1

0

0

k

VDD

2

C

1

µ

F

PGOOD

C

S

6

R

1

8

k

1

VOUT

2

VDD

3

FB

PGOOD

4

NC

RT8209A (WQFN-16L 3x3)

Typical Application Circuit

D

P

D

V

D

G

O

O

P

(TOP VIEW)

EN/DEM

BOOT

141

NC

0

0

13

UGATE

12

PHASE

11

CS

15

10

VDDP

96

87

PGND

4

C

5

3

0

1

.

µ

F

B

S

C

1

1

9

N

0

3

2

TON

3

VOUT

4

VDD

5

FB

PGOOD LGATE

GND

RT8209B (WQFN-14L 3.5x3.5)

T

O

N

5

0

k

R

B

O

T

O

R

U

G

A

T

E

P

H

A

S

E

L

G

A

T

E

P

G

N

D

FB

14

EN/DEM

TON

VOUT

VDD

FB

PGOOD

GND

2

3

4

5

6

7

BOOT

13

UGATE

12

PHASE

11

CS

10

VDDP

9

LGATE

8

PGND

RT8209C (TSSOP-14)

V

N

I

4

5

.

V

o

t

2

6

V

4

C

1

0

F

µ

1

Q

B

S

C

1

1

9

L

1

1

µ

N

0

3

S

Q2

H

S

R

7

*

C

7

*

*

8

R
1

2

k

9

R
3

0

k

V

= 1.05V

OUT

O

:

p

t

o

i

n

a

l

C

C

5

*

C

6

*

1

2

2

0

F

µ

M

M

/

E

D

C

C

EN/DEM

V

O

T

U

D

N

G

Functional Pin Description

Pin No.

RT8209A RT8209B/C

1 3 VOUT

2 4 VDD

3 5 FB

4 6 PGOOD

5, 14

17 (Exposed pa d)

Copyright 2014 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation.

2

©

RT 8209B :

15 (Exposed pa d)

Pin Name Pin Function

Outpu t Vo ltage Pin. Connect to the output of PWM converter.
VOUT is an input of the P WM controller.

Analog supply voltage input for the interna l analog integrated
circuit. Bypass to GND with a 1 μF c eramic capacitor.

Feed back Input Pin. Conne ct FB to a resistor voltage divider
from VOUT to GND to adjust VOUT f rom 0.75V to 3.3V
Power goo d signal open-drain output of PWM converter. This
pin will be pulled h igh when the o utput voltag e is within the
targe t range.
No interna l connection. The e xpo sed pad must b e soldered to

NC

a large PCB and conne c ted to GND for m aximum p ower
dissipation.

DS8209A/B/C-07 January 2014www.richtek.com

RT8209A/B/C

Pin No.

RT8209A RT8209B/C

6 7 GND Analog Ground.

7 8 PGND Power Ground.

8 9 LGATE

9 10 VDDP

10 1 1 CS

11 12 PHASE

12 1 3 UGAT E

13 1 4 BOOT

15 1 EN/D EM

16 2 TON

Pin Na me Pin Function

Low side N-MOSFET gate driver output for PWM. This pin
swings between GND and VDDP.

VDDP is the gate driver supply for external MOSFETs. Bypass
to GND wi th a 1μF ceramic capacitor.

Over Current Trip Point Set Input. Connect resistor from this
pin to signal ground to set threshold for both over current and
negative over current limit.

The UGATE High Si de G ate Dr iver Return. Also serves as
anode of over current comparator.

High side N-MOSFET floating gate driver output for the PWM
converter. This pin s wings between PHASE and BOOT.

Bootstrap Capacitor Connection for PWM Converter. Connect
to an external ceramic capacitor to PHASE.
Enable/Diode Emulation Mode Control Input. Connect to VDD
for diode-emulation mode, connect to GND for shutdown and
floating the pin for CCM mode.
On Time/Frequency Adjustment Pin. Connect to PHASE
through a resistor. TON is an input for the PWM controller.

Function Block Diagram

TRIG

­+

GM

On-time

Compute

1-SHOT

+

-

+

-

+

-

SS Timer

VOUT

TON

FB

VDD

EN/DEM

SS

(internal)

V

REF

125% V

70% V

REF

REF

OV

UV

90% V

­+

Latch

S1 Q

Latch

S1 Q

REF

Thermal

Shutdown

BOOT

R

QS

Min. T

OFF

QTRIG

1-SHOT

­+

Diode

Emulation

+

-

-

+

GM

DRV

DRV

10µA

UGATE

PHASE

VDDP

LGATE

PGND

PGOOD

CS

GND

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, P

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

@ T

D

= 25°C

A

Recommended Operating Conditions (Note 4)

z Input Voltage, V

z Supply Voltage, V

z Junction Temperature Range -------------------------------------------------------------------------------------------- −40°C to 125°C

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

Copyright 2014 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation.

©

4

---------------------------------------------------------------------------------------------------------- 4.5V to 26V

IN

, V

DD

---------------------------------------------------------------------------------------------- 4.5V to 5.5V

DDP

−40°C to 85°C

DS8209A/B/C-07 January 2014www.richtek.com

RT8209A/B/C

Electrical Characteristics

(V

= 15V, V

IN

PWM Controller

Quiescent Supply Current

Shutdown Current

FB Reference Voltage V
FB Input Bias Current VFB = 0.75V −1 0.1 1 μA
Output Voltage Range V

On Time

Minimum Off-Time 250 400 550 ns

VOUT Shutdown Discharge
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/D EM = 5V −10 -- 5 mV

F ault Protection

Current Limit Threshold

Current Limit Setting Range CS to GND 50 -- 200 mV
Output UV Threshold UVP detect 60 70 80 %

OVP Threshold V
OV Fault Delay FB forced above OV threshold -- 20 -- μs

Threshold

Current Limit Step Duration at
Soft-Start

UVP Blanking Time From EN signal going high -- 512 -- clks
Thermal Shutdown T

Driver On-Resista nce

= V

DD

= 5V, TA = 25°C, unless otherwise specified)

DDP

Parameter Symbol Test Conditions Min Typ Max Unit

I

V

VDD

I

V

VDDP

I

SHDN_VDD

I

SHDN_VDDP

REF

OUT

EN/DEM = 0V -- 1 10

V

0.75 -- 3.3 V

= 0.8V, EN/DEM = 5V -- 500 800

FB

= 0.8V, EN/DEM = 5V -- 1 10

FB

EN/DEM = 0V -- -- 1

= 4.5V to 5.5V 0.742 0.750 0.758 V

DD

V

PHASE

R

TON

= 12V, V

= 250kΩ

OUT

= 2.5V,

336 420 504 ns

μA

μA

EN/DEM = GND -- 20 -- Ω

GND − PHASE, VCS = 50mV 40 50 60
GND − PHASE, V

FB _O VP

OVP detect 120 125 130 %

Rising edge, PWM disabled below
this level

= 200mV 190 200 210

CS

4.1 4.3 4.5 V VDD Under Voltage Lockout

mV

Hysteresis -- 80 -- mV

Each step -- 128 -- clks

Hysteresis = 10°C -- 155 -- °C

SH DN

UGATE Drive Source R

UGATE Drive Sink R

LGATE Drive Source R

LGATE Drive Sink R
UGATE Driver Source/Sink

Current

UGATEsr

UGATEsk

LGATEsr

LGATEsk

LGATE Driver Source Current V

LGATE Driver Sink Current V

Dead Time

LGATE Rising (V

V

V
LGATE, High State -- 1 5 Ω
LGATE, Low State -- 0.5 2.5 Ω

V
V

− V

BOOT

− V

BOOT

− V

UGATE

− V

BOOT

= 2.5V -- 1 -- A

LGATE

= 2.5V -- 3 -- A

LGATE

= 5V -- 2 5 Ω

PHA SE

= 5V -- 1 5 Ω

PHA SE

= 2.5V,

PH ASE

PHA SE

= 5V

= 1.5V) -- 30 --

PHASE

-- 1 -- A

ns

UGATE Rising -- 30 --

Copyright 2014 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation.

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5

RT8209A/B/C

Parameter Symbol Test Conditions Min Typ Max Unit

Internal BOOT Charging Switch
On Resistance

Logic I/O

Logic Input Current

PGOOD

PGOOD Threshold

Fault Propagation Delay

Output Low Voltage I
Leakage Current High state, forced to 5V -- -- 1 μA

VDDP to BOOT, 10mA -- -- 80 Ω

EN/DEM Low -- -- 0.8

EN/DEM High 2.9 -- -- EN/DEM Logic Input Voltage

EN/DEM float -- 2 --

EN/DEM = VDD -- 1 5
EN/DEM = 0 −5 1 --

with respect to reference,

V

FB

PGOOD from Low to High
V

with respect to reference,

FB

PGOOD from High to Low

87 90 93

-- 125 --

μA

%

Hysteresis -- 3 --

Falling edge, FB forced below
PGOOD trip threshold

= 1mA -- -- 0.4 V

SI NK

-- 2.5 -- μs

V

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 expose pad for the package.

JC

Copyright 2014 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation.

6

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