Richtek RT8202LGQW, RT8202LZQW, RT8202MGQW, RT8202MZQW Schematic [ru]

Single Synchronous Buck Controller

RT8202L/M

General Description

The RT8202L/M PWM controller provides the 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 RT8202L/M 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 RT8202L is available in a

WQFN-16L 4x4 package and the RT8202M is available in

a WQFN-16L 3x3 package.

Ordering Information

RT8202L/M

Package Type
QW : WQFN-16L 4x4 (W-Type)
QW : WQFN-16L 3x3 (W-Type)

Lead Plating System
G : Green (Halogen Free and Pb Free)
Z : ECO (Ecological Element with
Halogen Free and Pb free)

L : WQFN-16L 4x4
M : WQFN-16L 3x3

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 4700ppm/

zz

zz

z Quick Load Step Response within 100ns

zz

zz

z 1% V

zz

zz

z Adjustable 0.75V to 3.3V Output Voltage Range

zz

zz

z 3V to 26V Battery Input Voltage Range

zz

zz

z Resistor Programmable Frequency

zz

zz

z Integrated Bootstrap Switch

zz

zz

z Over Voltage Protection

zz

zz

z Under Voltage Protection

zz

zz

z Voltage Ramp Soft-Start

zz

zz

z Built In Soft Discharge Output

zz

zz

z Power Good Indicator

zz

zz

z RoHS Compliant and 100% Halogen Free

zz

Sense (Lossless Limit)

DS(ON)

°°

°C R

°°

Accuracy over Line and Load

FB

Current Sensing

DS(ON)

Applications

z Notebook Computers

z CPU Core Supply

z Chipset/RAM Supply as Low as 0.75V

Pin Configurations

(TOP VIEW)

EN/DEM

GND

NC

1316 1415

17

PGND

BOOT

12

11

10

9

LGATE

UGATE

PHASE

OC

VDDP

VOUT

VDD

FB

PGOOD

TON

1

2

GND

3

4

5678

NC

WQFN-16L 4x4 (RT8202L)/

WQFN-16L 3x3 (RT8202M)

DS8202L/M-04 April 2011 www.richtek.com

1

RT8202L/M

Marking Information

RT8202LGQW RT8202MGQW

EK= : Product Code

EK=YM

DNN

YMDNN : Date Code

JJ=YM

DNN

JJ= : Product Code

YMDNN : Date Code

RT8202LZQW

EK : Product Code

EK YM

YMDNN : Date Code

DNN

Typical Application Circuit

1

6

T

V

P

D

D

V

5

D

O

G

O

P

C

C

D

M

E

/

M

1

C

1

R

6

,

1

E

7

(

x

p

9

V

2

R

2

V

2

C

4

P

1

5

E

o

s

e

d

P

a

d

)

G

7

PGND

RT8202MZQW

JJ : Product Code

JJ YM

YMDNN : Date Code

DNN

V

N

I

3

V

6

2

o

t

V

R

T

O

N

C

R

2

T

8

L

M

0

2

/

B

O

O

N

D

D

P

D

D

D

O

O

G

N

D

E

/

M

D

N

O

U

G

A

T

P

H

A

S

L

G

A

T

O

F

V

O

U

R

3

1

3

T

C

R

4

1

2

E

1

1

E

8

E

R

L

I

I

M

1

0

C

3

B

1

T

3

4

V

O

T

U

Q

1

Q

2

L

1

R

5

*

*

C

5

R

6

R

7

*

C

6

C

C

8

7

*

O

p

t

*

o

i

n

a

l

DS8202L/M-04 April 2011www.richtek.com

2

Function Block Diagram

TRIG

+

+

GM

-

-

SS Ramp

On-time

Compute

1-SHOT

+

-

+

-

VOUT

TON

FB

VDD

GND

SS (Internal)

115% V

70% V

REF

REF

OV

UV

90% V

­+

Latch

S1 Q

Latch

S1 Q

REF

Thermal

Shutdown

Comp

­+

R

QS

Min. T

OFF

QTRIG

1-SHOT

Emulation

PWM

Diode

RT8202L/M

DRV

DRV

20µA

+

-

BOOT

UGATE

PHASE

VDDP

LGATE

PGND

OC

EN/DEM

PGOOD

DS8202L/M-04 April 2011 www.richtek.com

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RT8202L/M

Functional Pin Description

Pin No. Pin Name Pin Function

1 VOUT

2 VDD

3 FB

4 PGOOD

5, 14 NC No Internal Connection.

6,

17 (Exposed Pad)

7 PGND Power Ground.

8 LGATE

9 VDDP

10 OC

11 PHASE

12 UGATE

13 BOOT

15 EN/DEM

16 TON

GND

Output Voltage Sense Pin. Connect this pin to the output of PWM converter.
VOUT is also for the output soft discharge when shutdown.

Analog Supply Voltage Input for Internal Analog Integrated Circuit. Bypass this
pin to GND with a 1μF ceramic capacitor.

Feedback Input of PWM Controller. Connect FB to a resistor voltage divider from
VOUT to GND to adjust the output voltage from 0.75V to 3.3V.

Power Good Signal Open-Drain Output of PWM Controller. This pin will be
pulled high when the output voltage is within the target range.

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

Low Side N-MOSFET Gate-Drive Output for PWM. This pin swings between
PGND to VDDP.

Gate Driver Supply for External MOSFETs. Bypass this pin to PGND with a 1μF
ceramic capacitor.

PWM Current Limit Setting and Sense. Connect a resistor between OC to
PHASE for current limit setting.

Inductor Connection. This pin is not only the zero-current-sense input for the
PWM converter, but also the UGATE high side gate driver return.

High Side N-MOSFET Floating Gate-Driver Output for PWM controller. This pin
swings between PHASE and BOOT.

Boost Capacitor connection for PWM Controller. Connect an external ceramic
capacitor from this pin to PHASE.

PWM Enable and Operation Mode Selection Input. Connect this pin to VDD for
diode-emulation mode, connect this pin to GND for shutdown mode and floating
the pin for CCM mode.

On Time/Frequency Adjustment Pin. Connect this pin to V
TON is an input of the PWM controller.

through a resistor.

IN

DS8202L/M-04 April 2011www.richtek.com

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RT8202L/M

Absolute Maximum Ratings (Note 1)

z Input Voltage, TON to GND ------------------------------------------------------------------------------------------------ –0.3V to 32V
z BOOT to PHASE ------------------------------------------------------------------------------------------------------------ –0.3V to 6V

z UGATE to PHASE

DC------------------------------------------------------------------------------------------------------------------------------- –0.3V to 6V

< 20ns ------------------------------------------------------------------------------------------------------------------------- −5V to 7.5V

z LGATEx to GND

DC------------------------------------------------------------------------------------------------------------------------------- –0.3V to 6V

< 20ns ------------------------------------------------------------------------------------------------------------------------- −2.5V to 7.5V

z PHASE to GND

DC------------------------------------------------------------------------------------------------------------------------------- –0.3V to 32V

< 20ns ------------------------------------------------------------------------------------------------------------------------- −8V to 38V

z PGND to GND ---------------------------------------------------------------------------------------------------------------- –0.3V to 0.3V
z VDD, VDDP, VOUT, EN/DEM, FB, PGOOD to GND ---------------------------------------------------------------- –0.3V to 6V
z OC to GND -------------------------------------------------------------------------------------------------------------------- –0.3V to 28V

z Power Dissipation, P

WQFN-16L 3x3 -------------------------------------------------------------------------------------------------------------- 1.471W

WQFN-16L 4x4 -------------------------------------------------------------------------------------------------------------- 1.852W

z Package Thermal Resistance (Note 2)

WQFN-16L 3x3, θJA--------------------------------------------------------------------------------------------------------- 68°C/W

WQFN-16L 3x3, θJC-------------------------------------------------------------------------------------------------------- 7.5°C/W

WQFN-16L 4x4, θJA--------------------------------------------------------------------------------------------------------- 54°C/W

WQFN-16L 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 Mode) ------------------------------------------------------------------------------------------------ 2kV

MM (Machine Mode) -------------------------------------------------------------------------------------------------------- 200V

@ TA = 25°C

D

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 --------------------------------------------------------------------------------------------- −40°C to 85°C

DS8202L/M-04 April 2011 www.richtek.com

------------------------------------------------------------------------------------------------------------ 3V to 26V

IN

, V

DD

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

DDP

5

RT8202L/M

Electrical Characteristics

(VDD = V

Quiescent Current IQ

TON Operating Current -- 15 --

Shutdown Current I

FB Referenc e Volta ge VFB V

FB Input Bias Current VFB = 0.75V −1 0.1 1 μA

Output Voltage Range V

On-Time tON V

Minimum Off-Time t

VOUT Shutdown Discharge
Resistance

Current Sensing

Current Limit Source
Current
Current Limiter Temperature
Coefficient
Current Comparator Offset
Voltage
Zero Crossing Threshold
Voltage

Fault Prote cti on

= 5V, VIN = 15V, V

DDP

EN/DEM

= VDD, R

= 1MΩ, T

TON

= 25°C, unless otherwise specified)

A

Parameter Symbol Test Conditions Min Typ Max Unit

SHDN

+ I

I

VDD

above the regulation point

I

+ I

VDD

I

-- 1 5

TON

, VFB = 0.8V, forced

VDDP

-- 1 10

VDDP

-- -- 1250 μA

EN/DEM = 0V −10 −1 -- μA

= 4.5V to 5.5V 0.742 0.75 0.758 V

DD

0.75 -- 3.3 V

OUT

= 15V, V

IN

250 400 550 ns

OFF

EN/DEM = GND, V

= 1.25V 267 334 401 ns

OUT

= 0.5V -- 20 -- Ω

OUT

LGATE = High 18 20 22 μA

On the basis of 25°C -- 4700 -- ppm/°C

TC

ICS

GND to OC −10 -- 10 mV

PHASE to GND, EN/DEM = 5V −10 -- 5 mV

μA

Current Limit Sense Voltage GND − PHASE, R

Output Under Voltage
Threshold
Over Voltage Protection
Threshold

Over Voltage Fault Delay

Under Voltage Lockout
Threshold
Under Voltage Lockout
Hysteresis

Soft-Start Ramp Time tSS

UVP detect, FB falling edge 60 70 80 %

V

UVP

V

OVP detect, FB rising edge 110 115 120 %

OVP

FB forced above
threshol d

V

UVLO

ΔV

UVLO

Falling edge, PWM disabled below
this level

-- 150 -- mV

From E N hi gh to in ternal VREF
reaches 0.71V (0Æ95%)

= 10kΩ 170 200 230 mV

ILIM

over voltage

-- 20 -- μs

3.7 3 .9 4.1 V

1.5 -- ms

Under Voltage Blank Time From EN signal going high -- 4.5 -- ms

Thermal Shutdown TSD -- 155 °C
Thermal Shutdown

Hysteresis

ΔT

-- 10 -- °C

SD

Driver On-Resistance

UGATE Driver Source R

UGATE Driver Sink R

UGATEs r

UGATEs k

UGATE, High State, BOOT to PHASE
forced to 5V
UGATE, Low State, BOOT to PHASE
forced to 5V

-- 2 -- Ω

-- 1.5 -- Ω

To be continued

DS8202L/M-04 April 2011www.richtek.com

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