Richtek RT8239A, RT8239B, RT8239C User Manual

RT8239A/B/C

®

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Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation.

©

Ordering Information

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.

High Efficiency, Main Power Supply Controller
for Notebook Computers

General Description

The RT8239A/B/C is a dual step down, Switch Mode Power

Supply (SMPS) controller which generates logic supply

voltages for battery powered systems. It includes two

Pulse Width Modulation (PWM) controllers adjustable

from 2V to 5.5V and also two fixed 5V/3.3V linear

regulators. One of the controllers (LDO5) provides

automatic switch over to the BYP1 input connected to

the main SMPS1 output for maximized efficiency. An

optional external charge pump can be monitored through

SECFB (RT8239B/C). Other features include on board

power up sequencing, a power good output, internal soft-

start, and a soft discharge output that prevents negative

voltage during shutdown.

A constant on-time PWM control scheme operates without

sense resistors and assures fast load transient response

while maintaining nearly constant switching frequency. To

eliminate noise in audio applications, an ultrasonic mode

is included, which maintains the switching frequency

above 25kHz. Moreover, a diode emulation mode

maximizes efficiency for light load applications. The

SMPS1/SMPS2 switching frequency can be adjustable

from 200kHz/233kHz to 400kHz/466kHz respectively.

The RT8239A/B/C is available in a WQFN-20L 3x3

package, and operates over an extended temperature range

from −40°C to 85°C.

Features

zz

zz

z 5.5V to 25V Input Voltage Range

zz

zz

z 2V to 5.5V Output Voltage Range

zz

zz

z No Current Sense Resistor Needed

zz

zz

z 5V/3.3V Linear Regulators

zz

zz

z 4700ppm/

°°

°°

°C R

DS(ON)

Current Sensing

zz

zz

z Internal Current Limit Soft-Start and Soft Discharge

Output

zz

zz

z Built In OVP/UVP/OCP

zz

zz

z Selectable Operation Mode with Switcher Enable

Control (RT8239A)

zz

zz

z SECFB Input Maintains Charge Pump Voltage

(RT8239B/C)

zz

zz

z Power Good Indicator (RT8239B/C includes SECFB)

zz

zz

z RoHS Compliant and Halogen Free

Applications

z Notebook computers

z System Power Supplies

z 3- and 4- Cell Li+ Battery-Powered Device

RT8239A/B/C

Package Type
QW : WQFN-20L 3x3 (W-Type)

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

Pin Function With
A : ENM
B : SECFB
C : SECFB, Ultrasonic Mode

RT8239A/B/C

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Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation.

Pin Configurations

(TOP VIEW)

RT8239B/CRT8239A

WQFN-20L 3x3

BYP1

BOOT1

ENTRIP2

TON

FB1

ENTRIP1

LDO3
LDO5

ENLDO

ENM

PGOOD

BOOT2

PHASE2 PHASE1

UGATE1

LGATE1

FB2

VIN

LGATE2

UGATE2

15

14

13

12

17181920

1

2

3

4

9876

GND

21

115

16

10

LDO3
LDO5

ENTRIP2

TON

FB1

ENTRIP1

ENLDO

SECFB

PGOOD

BOOT2

PHASE2

BYP1

BOOT1

PHASE1

UGATE1

LGATE1

FB2

VIN

LGATE2

UGATE2

15

14

13

12

17181920

1

2

3

4

9876

GND

21

115

16

10

Marking Information

JB=YM

DNN

JB YM

DNN

JB= : Product Code

YMDNN : Date Code

JB : Product Code

YMDNN : Date Code

RT8239A

JC=YM

DNN

JC YM

DNN

JC : Product Code

YMDNN : Date Code

JC= : Product Code

YMDNN : Date Code

RT8239B

JD=YM

DNN

JD YM

DNN

JD : Product Code

YMDNN : Date Code

JD= : Product Code

YMDNN : Date Code

RT8239C

RT8239A/B/C

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Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation.

Typical Application Circuit

Figure 1. RT8239A NB Main Supply Typical Application Circuit

C

8

3

.

3

V

RT8239A

PHASE1

LGATE1

BOOT1

UGATE1

VIN

11

16

19

17

18

PHASE2

LGATE2

BOOT2

UGATE2

FB2

V

I

N

1

0

µ

F

8

9

7

10

5

C

6

R

1

C

2

0

.

1

µ

F

5

.

5

V

t

o

2

5

V

21 (Exposed Pad)

GND

N3

L

2

C

7

0

.

1

µ

F

R

5

N4

R

6

6

.

5

k

+

N1

L

1

C

4

C

3

5

V

0

.

1

µ

F

R

2

N2

R

3

1

5

k

+

R

4

1

0

k

R

7

1

0

k

FB1

1

BYP1

20

1

0

µ

F

C

1

ENLDO

12

R

8

1

0

0

k

R

9

1

0

0

k

ENTRIP2

4

ENTRIP1

2

LDO3

15

C

9

4

.

7

µ

F

LDO5

14

PGOOD

6

R10

100k

C10

5

V

A

l

w

a

y

s

O

n

TON

3

R

TON

ENM

13

C

5

1

µ

F

Chip Enable

3

.

3

V

A

l

w

a

y

s

O

n

V

O

U

T

2

V

O

U

T

1

10µF

RT8239A/B/C

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Figure 2. RT8239B/C NB Main Supply Typical Application Circuit

RT8239B/C

PHASE1

LGATE1

BOOT1

UGATE1

VIN

11

16

19

17

18

PHASE2

LGATE2

BOOT2

UGATE2

FB2

V

I

N

1

0

µ

F

8

9

7

10

5

C

6

R

1

C

2

0

.

1

µ

F

5

.

5

V

t

o

2

5

V

21 (Exposed Pad)

GND

N3

L

2

C

7

C

8

3

.

3

V

0

.

1

µ

F

R

5

N4

R

6

6

.

5

k

+

N1

L

1

C

4

C

3

5

V

0

.

1

µ

F

R

2

N2

R

3

1

5

k

+

R

4

1

0

k

R

7

1

0

k

FB1

1

BYP1

20

1

0

µ

F

C

1

ENLDO

12

R

8

1

0

0

k

R

9

1

0

0

k

ENTRIP2

4

ENTRIP1

2

Off

On

LDO3

15

C9

4.7µF

LDO5

14

PGOOD

6

R10

100k

C10

5

V

A

l

w

a

y

s

O

n

TON

3

R

TON

C

1

1

0

.

1

µ

F

C

1

2

0

.

1

µ

F

SECFB

13

R

1

1

2

0

0

k

R

1

2

3

9

k

V

CP

C

1

3

0

.

1

µ

F

C

1

4

0

.

1

µ

F

C

5

1

µ

F

C

1

5

3

.

3

V

A

l

w

a

y

s

O

n

V

O

U

T

1

V

O

U

T

2

10µF

RT8239A/B/C

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Pin No. Pin Name Pin Function

1 FB1

SMPS1 Feedback Input. Connect FB1 to a resistive voltage divider from SMPS1
output to GND for adjustable output from 2V to 5.5V.

2 ENTRIP1

Channel 1 Enable and Current Limit Setting Input. Connect resistor to GND to set
the threshold for Channel 1 synchronous R

DS(ON)

sense. The GND-PHASE1

current limit threshold is 1/10th the voltage seen at ENTRIP1 over a 0.5V to 3V
range. There is an internal 10μA current source from LDO5 to ENTRIP1. Leave
ENTRIP1 floating or drive it above 4.5V to shut down channel 1.

3 TON ON-Time/Frequency Adjustment Input. Connect to GND with 56kΩ to 100kΩ.

4 ENTRIP2

Channel 2 Enable and Current Limit Setting Input. Connect resistor to GND to set
the threshold for Channel 2 synchronous R

DS(ON)

sense. The GND-PHASE2

current limit threshold is 1/10th the voltage seen at ENTRIP2 over a 0.5V to 3V
range. There is an internal 10μA current source from LDO5 to ENTRIP2. Leave
ENTRIP2 floating or drive it above 4.5V to shut down channel 2.

5 FB2

SMPS2 Feedback Input. Connect FB2 to a resistive voltage divider from SMPS2
output to GND for adjustable output from 2V to 5.5V.

Power Good Output for Channel 1 and Channel 2 (RT8239A).

6 PGOOD

Power Good Output for Channel 1, Channel 2 and SECFB (RT8239B/C).

7 BOOT2

Boost Flying Capacitor Connection for SMPS2. Connect to an external capacitor
according to the typical application circuits.

8 UGATE2

Upper Gate Driver Output for SMPS2. UGATE2 swings between PHASE2 and
BOOT2.

9 PHASE2

Switch Node for SMPS2. PHASE2 is the internal lower supply rail for the UGATE2
high side gate driver. PHASE2 is also the current sense input for the SMPS2.

10 LGATE2 Lower Gate Drive Output for SMSP2. LGATE2 swings between GND and LDO5.

11 VIN Supply Input for LDO5.

12 ENLDO

Master Enable Input. LDO5/LDO3 is enabled if it is within logic high level and
disabled if it is less than the logic low level. Leave ENLDO floating to default
enable LDO5/LDO3.

ENM
(RT8239A)

Mode Selection with Enable Input. Pull up to LDO5 (Ultrasonic mode) or LDO3
(DEM) to turn on both switch Channels. Short to GND for shutdown.

13

SECFB
(RT8239B/C)

Change Pump Feedback Pin. The SECFB is used to monitor the optional external
charge pump. Connect a resistive divider from the change pump output to GND to
detect the output. If SECFB drops below its feedback threshold, an ultrasonic
pulse occurs to refresh the charge pump driven by LGATE1 or LGATE2.
If SECFB drops below its UV threshold, the switcher channels stop working and
enter into discharge-mode. Pull up to LDO5 or LDO3 to disable SECFB UVP
function.

14 LDO5

5V Linear Regulator Output. LDO5 is the supply voltage for the low side MOSFET
driver and also the analog supply voltage for the device. Bypass a minimum 4.7μF
ceramic capacitor to GND

15 LDO3

3.3V Linear Regulator Output. Bypass a minimum 4.7μF ceramic capacitor to
GND.

16 LGATE1 Lower Gate Driver Output for SMPS1. LGATE1 swings between GND and LDO5.

17 PHASE1

Switch Node SMPS1. PHASE1 is the internal lower supply rail for the UGATE1
high side gate driver. PHASE1 is also the current sense input for the SMPS1.

Functional Pin Description

RT8239A/B/C

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Function Block Diagram

Pin No. Pin Name Pin Function

18 UGATE1

Upper Gate Driver Output for SMPS1. UGATE1 swings between PHASE1 and
BOOT1.

19 BOOT1

Boost Flying Capacitor Connection for SMPS1. Connect to an external
capacitor according to the typical application circuits.

20 BYP1 Switch Over Source Voltage Input for LDO5.

21 (Exposed Pad) GND

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

ENM (RT8239A)
SECFB (RT8239B/C)

SMPS2

PWM

Buck

Controller

BOOT2

UGATE2

PHASE2

LGATE2

GND

LDO5

FB2
ENTRIP2

PGOOD

SMPS1

PWM
Buck

Controller

BOOT1

UGATE1

PHASE1

LGATE1

LDO5

FB1

ENTRIP1

LDO5

REF

Switch Over Threshold

VIN

LDO5

On Time

TON

LDO3

LDO3

BYP1

Power-On
Sequence

Clear Fault Latch

ENLDO

+

-

LDO5

10µA

LDO5

10µA

RT8239A/B/C

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Recommended Operating Conditions (Note 4)

z Supply Input Voltage, VIN ----------------------------------------------------------------------------------------------- 5.5V to 25V

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

z Ambient Temperature Range -------------------------------------------------------------------------------------------- −40°C to 85°C

Absolute Maximum Ratings (Note 1)

z VIN, ENLDO to GND ------------------------------------------------------------------------------------------------------ −0.3V to 30V

z BOOTx to PHASEx ------------------------------------------------------------------------------------------------------- −0.3V to 6V

z ENTRIPx, FBx, TON, BYP1, PGOOD, LDO5, LDO3, ENM/SECFB to GND ------------------------------- −0.3V to 6V

z PHASEx to GND

DC----------------------------------------------------------------------------------------------------------------------------- −0.3V to 30V

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

z UGATEx to PHASEx

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 Power Dissipation, P

D

@ TA = 25°C

WQFN-20L 3x3 ------------------------------------------------------------------------------------------------------------ 3.33W

z Package Thermal Resistance (Note 2)

WQFN-20L 3x3, θJA------------------------------------------------------------------------------------------------------- 30°C/W

WQFN-20L 3x3, θJC------------------------------------------------------------------------------------------------------ 7.5°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 Model)---------------------------------------------------------------------------------------------- 2kV

Parameter Symbol Test Conditions Min Typ Max Unit

Input Supply

Rising Threshold -- 5.1 5.5

VIN Power On Reset

Falling Threshold 3.5 -- 4.5

V

VIN Shutdown Current

I

VIN_SHDN

V

ENLDO

= GND

-- 20 40

VIN Standby Supply Current

I

VIN_SBY

Both SMPS Off -- 250 350

μA

Quiescent Power Consumption

I

Q

Both SMPSs on, FBx = 2.1V,
BYP1 = 5V, ENM = 3.3V (RT8239A)

-- 5 7 mW

SMPS Output and FB Voltage

FBx, CCM Operation -- 2 --

FBx Regulation Voltage

V

FBx

FBx, DEM Operation 1.98 2.006 2.03

V

(VIN = 12V, V

ENLDO

= 5V, V

ENTRIPx

= 2V, V

BYP1

= 5V, No Load on LDO5, LDO3, T

A

= 25°C, unless otherwise specified)

Electrical Characteristics

RT8239A/B/C

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Parameter Symbol Test Conditions Min Typ Max Unit

Output Voltage Adjustable
Range

SMPS1, SMPS2 2 -- 5.5

SECFB Voltage

V

SECFB

RT8239B 1.92 2 2.08

V

On-Time

V

PHASE1

= 2V

-- 256 --

On-Time Pulse Width

t

UGATEx

V

IN

= 20V

R

TON

= 56kΩ

V

PHASE2

= 2V

-- 220 --

ns

Minimum Off-Time

t

LGATEx

V

FBx

= 1.8V

-- -- 400 ns

f

SMPS1

SMPS1 Operating Frequency 200 -- 400

Frequency Range

f

SMPS2

SMPS2 Operating Frequency 233 -- 466

kHz

Ultrasonic Mode Frequency

f

ASM

RT8239C, V

PHASEx

= 50mV

25 -- -- kHz

Soft-Start

Soft-Start Time

t

SSx

Zero to 200mV Current Limit Threshold
from ENTRIPx Enable

-- 2 -- ms

Current Sense

Current Limit Current Source

I

ENTRIPx

V

ENTRIPx

= 0.9V

9.4 10 10.6

μA

Temperature Coefficient of
I

ENTRIPx

On The Basis of 25°C

-- 4700 --

ppm/°C

Current Limit Adjustment
Range

V

ENTRIPx

= I

ENTRIPx

x R

ENTRIPx

0.5 -- 2.7 V

Current Limit Threshold

V

ENTRIPx

GND − PHASEx, V

ENTRIPx

= 2V

180 200 225 mV

Zero-Current Threshold

V

ZC

GND − PHASEx, FBx = 2.1V

-- 3 -- mV

Internal Regulator and Reference

V

BYP1

= 0V, I

LDO5

< 100mA

4.8 5 5.2

V

BYP1

= 0V, I

LDO5

< 100mA ,

6.5V < V

IN

< 25V

4.75 -- 5.25

LDO5 Output Voltage

V

LDO5

V

BYP1

= 0V, I

LDO5

< 50mA,

5.5V < V

IN

< 25V

4.75 -- 5.25

V

LDO5 Output Current I

SHORT5

V

BYP1

= 0V, V

LDO5

= 4.5V -- 225 -- mA

5V Switchover Threshold V

BYP1TH

Falling Edge, Rising Edge with FB1
Regulation Point

4.53 4.66 4.79 V

5V Switch R

DS(ON)

R

BYPSW

V

BYP1

= 5V, I

LDO5

= 50mA -- 1.5 3 Ω

V

BYP1

= 0V, I

LDO3

< 100mA 3.2 3.3 3.46 V

LDO3 Output Voltage V

LDO3

V

BYP1

= 5V, I

LDO3

< 100mA 3.2 3.3 3.46

LDO3 Output Current I

SHORT3

V

BYP1

= 0V, V

LDO3

= 2.9V -- 150 -- mA

UVLO

Rising Edge -- 4.35 4.5

LDO5 UVLO Threshold V

UVLO5

Falling Edge 3.9 4.05 4.2

V

LDO3 UVLO Threshold V

UVLO3

Both SMPS Off -- 2.2 --

Power Good

PGOOD Threshold V

PGOOD

PGOOD Detect, Rising edge with
soft-start delay time. Hysteresis = 2.5%

−14 −10 −6 %

PGOOD Propagation Delay t

PD_PGOOD

Falling Edge -- 5 -- μs