Richtek RT8202AGQW, RT8202APQW, RT8202BGQW, RT8202GQW, RT8202PQW Schematic [ru]

®

Single Synchronous Buck Controller

RT8202/A/B

General Description

The RT8202/A/B PWM controller provides high efficiency ,
excellent transient response, a nd high DC output a ccuracy
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 sche me handles wide
input/output voltage ratios with ea se and provides 100ns
“instant-on” response to load tran sients while maintaining
a relatively constant switching frequency .

The RT8202/A/B 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 MOSFET s. The buck conversion allows this device
to directly step down high voltage batteries for the highest
possible efficiency . The RT8202/A/B is intended f or CPU
core, chipset, DRAM, or other low voltage supplies as
low as 0.75V. RT8202 is available in WQFN-16L 4x4,
RT8202A is available in WQF N-16L 3x3 and R T8202B is
available in WQF N-14L 3.5x3.5 pack ages.

Features



Ultra-High Efficiency







 Resistor Programmable Current Limit by Low Side



R

Sense (Lossless Limit) or Sense Resistor

DS(ON)

(High Accuracy)



 Quick Load Step Response within 100ns





 1% V





 Adjustable 0.75V to 3.3V Output Range





 4.5V to 26V Battery Input Range





 Resistor Programmable Frequency





 Over/Under Voltage Protection





 2 Steps Current Limit During Soft-Start





 Drives Large Synchronous-Rectifier FET s





 Power Good Indicator





 RoHS Compliant and 100% Lead (Pb)-Free



Accuracy over Line and Load

OUT

Applications

 Notebook Computers
 CPU Core Supply
 Chipset/RAM Supply a s Low as 0.75V

Pin Configurations

Ordering Information

(TOP VIEW)

RT8202/A/B

Package Type
QW : WQFN-16L 4x4 (W-Type) (RT8202)
QW : WQFN-16L 3x3 (W-Type) (RT8202A)
QW : WQFN-14L 3.5x3.5 (W-Type) (RT8202B)

VOUT

VDD

FB

PGOOD

Lead Plating System
P : Pb Free
G : Green (Halogen Free and Pb Free)

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.

Marking Information

WQFN-16L 4x4/WQFN-16L 3x3

TON

VOUT

VDD

FB

PGOOD LGATE

For marking information, contact our sales re presentative
directly or through a Richtek distributor located in your
area.

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

DS8202/A/B-07 April 2014 www.richtek.com

©

TON

EN/DEM

BOOT

NC

13141516

GND

17

8765

PGND

BOOT

141

15

87

PGND

12
11
10

9

LGATE

13
12
11

10

96

1
2
3
4

2
3
4
5

GND

NC

EN/DEM

GND

GND

WQFN-14L 3.5x3.5

UGATE
PHASE

OC
VDDP

UGATE
PHASE
OC
VDDP

1

RT8202/A/B

Typical Application Circuit

V

DDP

5V

C

1µF

1

D1

BAT254

R3

1M

V

IN

4.5V to 26V

PGOOD

CCM/DEM

V

DDP

5V

C

1µF

2

R

51k

R1

1

0
C

1µF

2

RT8202/A/B

T

O

N

V

D

D

P

VDD

PGOOD
EN/DEM
GND
PGND

BOOT

UGATE
PHASE

LGATE

OC

FB

VOUT

Figure 1. Output Voltage Setting for V

D1

BAT254

1

R4

2.2

R5 0

R

6

R3

1M

3

C
0

.

1

µ

1

0

k

AO4702

< 3.3V Application

OUT

F

Q2

V

IN

4.5V to 26V

C4

1

0

µ

F

V

O

U

1

Q
A

O

4

7

0

2

L

1

4

2

.

µ

H

R7

C6

C

5

C

8

0

.

1

µ

F

R8
12k

R9
20k

T

C7
220µF

C

2

O

O

G

P

CCM/DEM

R

51k

R1

0

1

C

2

1µF

D

RT8202/A/B

T

N

O

V

D

D

P

VDD

PGOOD
EN/DEM
GND
PGND

BOOT

UGATE
PHASE

LGATE

OC

FB

VOUT

Figure 2. Output Voltage Setting for V

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

©

R4

2.2

R5 0

R6 10k

C

3
1

F

0

µ

.

Q2

AO4702

> 3.3V Application

OUT

Q
A

4

1

0

µ

F

V

1

O

4

7

0

2

L

1

2

.

4

H

µ

R7

C

5

C

8

0

.

1

µ

F

R8

R9

V

U

O

O

C6

R

T

F

B

R11

DS8202/A/B-07 April 2014www.richtek.com

2

U

1

0

T

C7
220µF

Functional Pin Description

RT8202/A/B

Pin No.

RT8202/A RT8202B

1 3 VOUT

2 4 VDD

3 5 FB

4 6 PGOOD

5, 14 -- NC No Internal Connection.

6, 17

(Exposed Pad)

7 8 PGND Power Ground.
8 9 LGATE

9 10 VDDP

10 11 OC

11 12 PHASE

12 13 UGATE

13 14 BOOT

15 1 EN/DEM

16 2 TON

7, 15

(Exposed Pad)

Pin Name Pin Function

VOUT Sense Input. Connect to the output of PW M converter. VOUT
is an input of the PWM controller.

Analog Supply Voltage Input for the internal analog integrated circuit.
Bypass to GND with a 1F ceramic capacitor.

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

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

GND

Ground for Analog Circuitry. 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 GND and VDDP.

VDDP is the gate driver supply for the external MOSFETs. Bypass to
GND with a 1F 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 the PWM
converter. This pin swings between PHASE and BOOT.

Boost Capacitor Connection for PWM Converter. Connect an external
ceramic capacitor to PHASE and an external diode to VDDP.

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

VIN Sense Input. Connect to VIN through a resistor. TON is an input
of the PWM controller.

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

DS8202/A/B-07 April 2014 www.richtek.com

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3

RT8202/A/B

Function Block Diagram

TRIG

-

GM

+

On-time

Compute

1-SHOT

+

-

REF

+

-

­+

SS Timer

VOUT

TON

FB

VDD

GND

SS(Internal)

0.75V V

115% V

70% V

REF

REF

OV

UV

90% V

Comp

­+

Latch

S1 Q

Latch

S1 Q

REF

Thermal

Shutdown

R

QS

Min. T

OFF

QTRIG

1-SHOT

Diode

­+

Emulation

DRV

DRV

20uA

+

-

BOOT
UGATE
PHASE

VDDP
LGATE
PGND

OC

EN/DEM

PGOOD

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

©

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RT8202/A/B

Absolute Maximum Ratings (Note 1)

 Input V oltage, TON to GN D ---------------------------------------------------------------------------------------------- −0.3V to 32V
 BOOT to GND -------------------------------------------------------------------------------------------------------------- −0.3V to 38V
 PHASE to BOOT ---------------------------------------------------------------------------------------------------------- −6V to 0.3V
 V DD, V DDP, VOUT, EN/DEM, FB, PGOOD to GND -------------------------------------------------------------- −0.3V to 6V
 UGA TE to PHASE -------------------------------------------------------------------------------------------------------- −0.3V to 6V
 OC to GND ------------------------------------------------------------------------------------------------------------------ −0.3V to 32V
 LGA TE t o G ND ------------------------------------------------------------------------------------------------------------- −0.3V to 6V
 PGND to GND -------------------------------------------------------------------------------------------------------------- −0.3V to 0.3V
 Power Dissipation, P

WQFN-16L 4x4 ------------------------------------------------------------------------------------------------------------ 1.852W
WQFN-16L 3x3 ------------------------------------------------------------------------------------------------------------ 1.471W
WQFN-14L 3.5x3.5 ------------------------------------------------------------------------------------------------------- 1.667W

 Package Thermal Resistance (Note 2)

WQF N-16L 4x4, θJA------------------------------------------------------------------------------------------------------- 54°C/W
WQFN-16L 4x4, θJC------------------------------------------------------------------------------------------------------ 7°C/W
WQF N-16L 3x3, θJA------------------------------------------------------------------------------------------------------- 68°C/W
WQFN-16L 3x3, θJC------------------------------------------------------------------------------------------------------ 7.5°C/W
WQF N-14L 3.5x3.5, θJA-------------------------------------------------------------------------------------------------- 60°C/W
WQFN-14L 3.5x3.5, θJC------------------------------------------------------------------------------------------------- 7°C/W

 Lead T e mperature (Soldering, 10 sec.)------------------------------------------------------------------------------- 26 0°C
 Junction T e mperature ---------------------------------------------------------------------------------------------------- 150°C
 Storage T emperature Range -------------------------------------------------------------------------------------------- −65°C to 150°C
 ESD Susceptibility (Note 3)

HBM (Human Body Mode) ---------------------------------------------------------------------------------------------- 2kV
MM (Ma chine Mode)------------------------------------------------------------------------------------------------------ 200V

@ TA = 25°C

D

Recommended Operating Conditions (Note 4)

 Input V oltage, V
 Supply Voltage, V
 Junction T emperature Range--------------------------------------------------------------------------------------------
 Ambient T emperature Range--------------------------------------------------------------------------------------------

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

IN

, V

DD

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

DDP

−40°C to 125°C

−40°C to 85°C

Electrical Characteristics

(V

= V

DD

PWM Controller

Quiescent Supply Current VDD + VDDP, FB = 0.8V -- -- 1250 A
TON Operating Current R

Shutdown Current I

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

DS8202/A/B-07 April 2014 www.richtek.com

DDP

= 5V, V

= 15V, V

IN

= 1.25V, EN/DEM = VDD, R

OUT

TON

= 1MΩ, T

= 25°C, unless otherwise specified)

A

Parameter Symbol Test Conditions Min Typ Max Unit

= 1M -- 15 -- A

TON

VDD + VDDP -- 1 10 A
TON -- 1 5 A

SHDN

EN/DEM = 0V 10 1 -- A

©

5

RT8202/A/B

Parameter Symbol Test Conditions Min Typ Max Unit

FB Reference Volt age VFB V

= 4.5 to 5.5V 0.742 0.75 0.758 V

DD

FB Input Bias Current FB = 0.75V 1 0.1 1 A
Output Voltage Range V
On-Time VIN = 15V, V

0.75 -- 3.3 V

OUT

= 1.25V, R

OUT

= 1M 267 334 401 ns

TON

Minimum Off-Time 250 400 550 ns
V

Shutdown Discharge

OUT

Resistance

EN/DEM = GND -- 20 -- 

Current Sensing

ILIM Source Current LGATE = High 18 20 22 A
Current Comparator Offset GND  OC 10 -- 10 mV

Current Limit Setting Range R

2.5 -- 10 k

ILIM

Zero Crossing Threshold GND  PHASE, EN/DEM = 5V 10 -- 5 mV

Fault Protection

Current Limit Sense
Voltage

V

RILIM

GND  PHASE, R
GND  PHASE, R

= 2.5k 35 50 65

ILIM

= 10k 170 200 230

ILIM

mV

Output UV Threshold 60 70 80 %
OVP Threshold

With respect to error comparator
threshold

10 15 20 %
OV Fault Delay FB forced above OV threshold -- 20 -- s
VDD UVLO Threshold

Soft-Start Ramp Time

Rising edge, Hysteresis = 20mV,
PWM disabled below this level
From EN high to internal V

REF

reach

0.71V (095%)

4.1 4.3 4.5 V

-- 1.35 -- ms

UV Blank Tim e From EN signal going high -- 3.1 -- ms
Thermal Shutdown -- 155 -- °C

Thermal Shutdown
Hysteresis

-- 10 -- °C

Driver On-Resistance

UGATE Driver Pull Up BOOT  PHASE = 5V -- 1.5 5 
UGA TE Driver Sink R

UGATEsk

BOOT  PHASE = 5V -- 1.5 5 
LGATE Driver Pull Up LGATE, High State (Source) -- 1.5 5 
LGATE Driver Pull Down LGATE, Low State (Sink) -- 0.6 2.5 

UGA TE Driver Source/Sink
Current
LGATE Driver Source
Current

LGATE forced to 2.5V -- 1 -- A

UGATE  PHASE = 2.5V,
BOOT  PHASE = 5V

-- 1 -- A

LGATE Driver Sink Current LGATE forced to 2.5V -- 3 -- A

LGATE Rising (PHASE = 1.5V) -- 30 --

Dead Time

UGATE Rising -- 30 --

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6

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