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

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RT8202L/M

Single Synchronous Buck Controller

General Description

The RT8202L/M PWM controller provides the 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 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.

Features

zUltra-High Efficiency

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

z4700ppm/°C RDS(ON) Current Sensing

zQuick Load Step Response within 100ns

z1% VFB Accuracy over Line and Load

zAdjustable 0.75V to 3.3V Output Voltage Range

z3V to 26V Battery Input Voltage Range

zResistor Programmable Frequency

zIntegrated Bootstrap Switch

zOver Voltage Protection

zUnder Voltage Protection

zVoltage Ramp Soft-Start

zBuilt In Soft Discharge Output

zPower Good Indicator

zRoHS Compliant and 100% Halogen Free

Ordering Information

Applications

z Notebook Computers

RT8202L/M

 

 

 

 

 

 

 

 

 

 

 

 

Package Type

z CPU Core Supply

 

 

 

 

z Chipset/RAM Supply as Low as 0.75V

 

 

 

 

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

 

 

 

 

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

 

Lead Plating System

Pin Configurations

 

 

G : Green (Halogen Free and Pb Free)

 

(TOP VIEW)

 

Z : ECO (Ecological Element with

 

 

 

 

 

 

 

 

Halogen Free and Pb free)

 

TON

EN/DEM

NC

BOOT

 

L : WQFN-16L 4x4

 

 

 

 

 

 

 

 

M : WQFN-16L 3x3

 

 

 

 

 

 

Note :

 

16

15

14

13

 

VOUT

1

 

 

12

UGATE

 

 

 

Richtek products are :

VDD

2

GND

11

PHASE

` RoHS compliant and compatible with the current require-

FB

3

10

OC

 

17

ments of IPC/JEDEC J-STD-020.

PGOOD

4

 

9

VDDP

 

 

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

 

5

6

7

8

 

 

NC

GND

PGND

LGATE

 

 

 

 

 

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

 

 

 

JJ= : Product Code

 

 

 

 

 

 

 

EK=YM

 

YMDNN : Date Code

 

JJ=YM

 

YMDNN : Date Code

 

DNN

 

 

 

DNN

 

 

 

 

 

 

 

 

 

 

RT8202LZQW

 

RT8202MZQW

 

 

 

EK : Product Code

 

 

 

JJ : Product Code

 

EK YM

YMDNN : Date Code

 

JJ YM

 

YMDNN : Date Code

 

DNN

 

 

DNN

 

 

 

 

 

 

 

 

 

Typical Application Circuit

 

 

 

RT8202L/M

 

 

16

TON

BOOT

 

 

9

V

 

VDDP

 

DDP

 

 

UGATE

5V

 

R2

 

C1

 

 

PHASE

 

 

2

VDD

 

 

C2

 

 

R1

 

LGATE

 

 

 

PGOOD

 

4

PGOOD

OC

 

 

 

CCM/DEM

 

15

EN/DEM

FB

 

 

 

6 , 17 (Exposed Pad)

GND

 

 

 

 

 

 

 

7

PGND

VOUT

 

 

 

* Optional

 

 

 

 

 

 

V

 

 

 

 

 

 

IN

26V

 

 

 

 

 

3V to

 

 

 

 

R

 

 

 

 

 

 

TON

 

 

 

 

 

 

 

 

 

C4

 

 

13

R3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

V

12

R4

C3

 

 

 

OUT

 

 

 

 

Q1

 

 

 

 

 

 

 

 

 

L1

 

 

11

 

 

 

 

 

 

 

 

 

 

 

8

 

Q2

R5*

 

C8

 

 

 

 

R

 

 

 

 

 

10

ILIM

 

 

C5*

R6

C6*

 

 

 

 

 

 

 

 

 

 

 

 

3

 

 

 

 

 

C7*

 

 

 

 

 

 

 

 

 

 

 

R7

 

1

 

 

 

 

 

 

www.richtek.com

DS8202L/M-04 April 2011

2

 

Richtek RT8202LGQW, RT8202LZQW, RT8202MGQW, RT8202MZQW Schematic

RT8202L/M

Function Block Diagram

 

 

TRIG

 

 

 

 

 

 

VOUT

 

 

On-time

 

 

 

 

 

 

 

Compute

 

 

 

 

 

 

TON

 

 

 

 

 

 

 

 

 

1-SHOT

 

 

R

 

 

 

 

 

 

 

 

 

 

 

 

 

+

 

 

- Comp

 

 

BOOT

SS (Internal)

+

 

 

 

PWM

 

 

 

 

 

 

 

GM

 

 

+

S

Q

DRV

UGATE

 

-

-

 

 

 

 

 

 

 

 

 

 

 

PHASE

 

 

 

 

 

 

Min. TOFF

 

 

 

 

 

 

 

 

Q

TRIG

 

 

 

 

 

+

OV

Latch

1-SHOT

 

 

VDDP

115% VREF

S1

Q

 

 

DRV

LGATE

-

 

Latch

 

 

FB

 

+

UV

 

 

 

PGND

 

S1

Q

 

Diode

 

 

70% VREF

 

-

 

 

 

 

 

 

 

 

 

-

 

Emulation

 

 

 

 

 

 

 

 

 

 

 

 

 

90% VREF

 

 

 

 

 

 

 

+

 

 

20µA

 

 

 

SS Ramp

Thermal

 

 

 

VDD

 

 

 

+

OC

 

 

 

 

Shutdown

 

 

GND

 

 

 

 

 

 

 

-

 

 

 

EN/DEM

 

 

PGOOD

 

 

 

DS8202L/M-04 April 2011

www.richtek.com

3

RT8202L/M

Functional Pin Description

Pin No.

Pin Name

Pin Function

1

VOUT

Output Voltage Sense Pin. Connect this pin to the output of PWM converter.

VOUT is also for the output soft discharge when shutdown.

 

 

2

VDD

Analog Supply Voltage Input for Internal Analog Integrated Circuit. Bypass this

pin to GND with a 1μF ceramic capacitor.

 

 

3

FB

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.

 

 

4

PGOOD

Power Good Signal Open-Drain Output of PWM Controller. This pin will be

pulled high when the output voltage is within the target range.

 

 

5, 14

NC

No Internal Connection.

6,

GND

Analog Ground. The exposed pad must be soldered to a large PCB and

17 (Exposed Pad)

connected to GND for maximum power dissipation.

7

PGND

Power Ground.

 

 

 

8

LGATE

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

PGND to VDDP.

 

 

9

VDDP

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

ceramic capacitor.

 

 

10

OC

PWM Current Limit Setting and Sense. Connect a resistor between OC to

PHASE for current limit setting.

 

 

11

PHASE

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.

 

 

12

UGATE

High Side N-MOSFET Floating Gate-Driver Output for PWM controller. This pin

swings between PHASE and BOOT.

 

 

13

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

15

EN/DEM

diode-emulation mode, connect this pin to GND for shutdown mode and floating

 

 

the pin for CCM mode.

16

TON

On Time/Frequency Adjustment Pin. Connect this pin to VIN through a resistor.

 

 

TON is an input of the PWM controller.

www.richtek.com

DS8202L/M-04 April 2011

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