Richtek RT8243AZQW, RT8243BZQW, RT8243CZQW Schematic [ru]

Loading...

®

RT8243A/B/C

High Efficiency, Main Power Supply Controller for Notebook Computers

General Description

The RT8243A/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 (RT8243B/C). Other features include on board power up sequencing, a power good output, internal softstart, 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 RT8243A/B/C is available in a WQFN-20L 3x3 package, and operates over an extended temperature range from −40°C to 85°C.

Features

5.5V to 25V Input Voltage Range

2V to 5.5V Output Voltage Range

No Current Sense Resistor Needed

5V/3.3V Linear Regulators

4700ppm/°C RDS(ON) Current Sensing

Internal Current Limit Soft-Start and Soft Discharge Output

Built In OVP/UVP/OCP

Selectable Operation Mode with Switcher Enable Control (RT8243A)

SECFB Input Maintains Charge Pump Voltage (RT8243B/C)

Power Good Indicator (RT8243B/C includes SECFB)

RoHS Compliant and Halogen Free

Applications

Notebook computers

System Power Supplies

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

Ordering Information

RT8243A/B/C

Package Type

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

Lead Plating System

Z : ECO (Ecological Element with Halogen Free and Pb free)

Pin Function With A : ENM

B : SECFB

C : SECFB, Ultrasonic Mode

Note :

Richtek products are :

RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.

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

Copyright ©2014 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

DS8243A/B/C-07 November 2014

www.richtek.com

 

1

RT8243A/B/C

Pin Configurations

 

BYP1 BOOT1 UGATE1 PHASE1 LGATE1

 

 

20 19

18 17

 

16

 

FB1

1

 

 

 

 

15

LDO3

ENTRIP1

2

GND

 

14

LDO5

TON

3

 

13

ENM

ENTRIP2

4

 

 

21

 

12

ENLDO

FB2

5

 

 

 

 

11

VIN

 

6

7

8

9

 

10

 

 

PGOOD

BOOT2

UGATE2

PHASE2

LGATE2

 

 

RT8243A

 

 

Marking Information

RT8243AZQW

8A : Product Code

8A YM YMDNN : Date Code

DNN

RT8243CZQW

0B : Product Code

0B YM YMDNN : Date Code

DNN

(TOP VIEW)

WQFN-20L 3x3

 

BYP1 BOOT1 UGATE1 PHASE1 LGATE1

 

 

20 19

18 17

16

 

FB1

1

 

 

 

15

LDO3

ENTRIP1

2

GND

14

LDO5

TON

3

13

SECFB

ENTRIP2

4

 

 

21

12

ENLDO

FB2

5

 

 

 

11

VIN

 

6

7

8

9

10

 

 

PGOOD

BOOT2

UGATE2

PHASE2

LGATE2

 

 

RT8243B/C

 

RT8243BZQW

7A : Product Code

7A YM YMDNN : Date Code

DNN

Copyright ©2014 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

www.richtek.com

DS8243A/B/C-07 November 2014

2

 

RT8243A/B/C

Typical Application Circuit

VIN 5.5V to 25V

V

 

OUT1

+

5V

 

C3

C5

Optional

C1

10µF

N1

L1

N2

R3 15k

R4 10k

R1

C2 0.1µF

R2

C4 0.1µF

RTON

11

12

18

19

17

16

1

3

20

Chip Enable

13

21 (Exposed Pad)

RT8243A

 

VIN

UGATE2

8

ENLDO

BOOT2

7

 

UGATE1

 

 

BOOT1

PHASE2

9

 

10

 

LGATE2

PHASE1

 

 

LGATE1

FB2

5

 

ENTRIP2

4

FB1

 

2

TON

ENTRIP1

 

15

BYP1

LDO3

 

 

ENM

LDO5

14

GND

PGOOD

6

 

 

 

 

 

 

C6

 

 

N3

 

10µF

 

 

 

 

 

R5

 

 

 

 

C7

 

L2

 

 

0.1µF

 

 

V

 

 

 

 

 

 

 

+

OUT2

 

 

 

3.3V

 

N4

 

C8

 

 

 

 

R6

 

 

 

 

6.5k

 

R8

 

 

R7

 

100k

 

 

 

 

 

10k

 

 

 

 

 

R9

 

 

 

 

100k

 

 

 

 

C9

 

 

3.3V Always On

 

 

 

 

 

4.7µF

 

 

 

 

 

C10

 

5V Always On

 

R10

 

 

 

4.7µF

 

 

100k

 

 

 

 

 

 

Figure 1. RT8243ANB Main Supply Typical Application Circuit

Copyright ©2014 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

DS8243A/B/C-07 November 2014

www.richtek.com

 

3

RT8243A/B/C

VIN 5.5V to 25V

C1 10µF

N1

V

 

L1

 

 

OUT1

+

 

5V

 

 

C3

N2

 

 

R3

 

 

15k

 

 

R4

 

 

10k

C5

 

 

Optional

 

 

 

 

C13

 

 

0.1µF

C14 0.1µF

C15

VCP

 

 

 

R1

 

 

 

RT8243B/C

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

11

VIN

UGATE2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C2

 

 

12

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0.1µF

 

 

ENLDO

BOOT2

 

 

 

18

 

 

 

 

 

 

 

 

 

 

UGATE1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R2

 

19

BOOT1

PHASE2

 

 

 

 

 

 

C4

 

 

 

 

 

 

 

 

 

 

 

 

 

LGATE2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0.1µF

17

PHASE1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

16

LGATE1

FB2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

 

ENTRIP2

 

 

 

 

 

 

 

 

 

 

 

 

FB1

 

 

 

 

RTON

 

 

3

TON

ENTRIP1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

20

 

 

 

 

 

 

 

 

 

 

 

 

 

BYP1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C11

 

 

 

 

 

 

0.1µF

 

 

 

 

LDO3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C12

 

 

 

 

LDO5

 

0.1µF

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R11

 

 

 

 

PGOOD

200k

13

SECFB

 

 

 

 

 

 

 

 

 

 

R12

GND

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

39k

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

8

7

9

10

5

N3

R5

C7 0.1µF

N4

C6

10µF

L2

+

C8

R6 6.5k

 

R8

 

R7

4

100k

 

 

10k

 

 

 

R9

 

 

2

100k

 

 

 

 

On

 

 

 

 

 

 

Off

15

 

 

3.3V Always On

 

C9

 

 

 

 

 

4.7µF

 

 

14

 

C10

5V Always On

 

 

 

R10

 

 

4.7µF

 

 

100k

 

6

 

 

 

 

 

21 (Exposed Pad)

VOUT2 3.3V

Figure 2. RT8243B/C NB Main Supply Typical Application Circuit

Copyright ©2014 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

www.richtek.com

DS8243A/B/C-07 November 2014

4

 

RT8243A/B/C

Functional Pin Description

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.

 

 

 

 

Channel 1 Enable and Current Limit Setting Input. Connect resistor to GND to set

2

ENTRIP1

the threshold for Channel 1 synchronous RDS(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 10 A 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 56k to 100k .

 

 

 

 

 

Channel 2 Enable and Current Limit Setting Input. Connect resistor to GND to set

4

ENTRIP2

the threshold for Channel 2 synchronous RDS(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 10 A 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.

 

 

6

PGOOD

Power Good Output for Channel 1 and Channel 2 (RT8243A).

 

Power Good Output for Channel 1, Channel 2 and SECFB (RT8243B/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.

 

 

 

 

 

Master Enable Input. LDO5/LDO3 is enabled if it is within logic high level and

12

ENLDO

disabled if it is less than the logic low level. Leave ENLDO floating to default

 

 

enable LDO5/LDO3.

 

ENM

Mode Selection with Enable Input. Pull up to LDO5 (Ultrasonic mode) or LDO3

 

(RT8243A)

(DEM) to turn on both switch Channels. Short to GND for shutdown.

 

 

Change Pump Feedback Pin. The SECFB is used to monitor the optional external

13

 

charge pump. Connect a resistive divider from the change pump output to GND to

SECFB

detect the output. If SECFB drops below its feedback threshold, an ultrasonic

 

pulse occurs to refresh the charge pump driven by LGATE1 or LGATE2.

 

(RT8243B/C)

 

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.

 

 

5V Linear Regulator Output. LDO5 is the supply voltage for the low side MOSFET

14

LDO5

driver and also the analog supply voltage for the device. Bypass a minimum 4.7 F

 

 

ceramic capacitor to GND

15

LDO3

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

GND.

 

 

Copyright ©2014 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

DS8243A/B/C-07 November 2014

www.richtek.com

 

5

Richtek RT8243AZQW, RT8243BZQW, RT8243CZQW Schematic

RT8243A/B/C

Pin No.

Pin Name

Pin Function

 

 

 

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.

 

 

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.

 

 

Function Block Diagram

BOOT1

 

 

 

UGATE1

 

 

 

PHASE1

LDO5

 

LDO5

 

 

 

SMPS1

SMPS2

 

LGATE1

PWM

PWM

 

Buck

Buck

 

 

Controller

Controller

LDO5

 

LDO5

 

 

 

 

 

10µA

 

10µA

 

 

 

FB1

 

 

 

ENTRIP1

 

 

 

TON

On Time

 

 

BYP1

Switch Over Threshold

 

 

 

 

 

 

+ -

 

 

LDO5

 

 

 

 

LDO5

REF

LDO3

VIN

 

Power On

 

 

Sequence

 

ENLDO

 

 

 

Clear Fault Latch

 

BOOT2

UGATE2

PHASE2

LGATE2

FB2

ENTRIP2

ENM (RT8243A) SECFB (RT8243B/C)

PGOOD

GND

LDO3

Copyright ©2014 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

www.richtek.com

DS8243A/B/C-07 November 2014

6

 

 

RT8243A/B/C

Absolute Maximum Ratings (Note 1)

 

VIN, ENLDO to GND ------------------------------------------------------------------------------------------------------

−0.3V to 30V

BOOTx to PHASEx

 

DC -----------------------------------------------------------------------------------------------------------------------------

−0.3V to 6V

< 20ns -----------------------------------------------------------------------------------------------------------------------

−2.5V to 6.3V

ENTRIPx, FBx, TON, BYP1, PGOOD, LDO5, LDO3, ENM/SECFB to GND -------------------------------

−0.3V to 6V

PHASEx to GND

 

DC -----------------------------------------------------------------------------------------------------------------------------

−0.3V to 30V

< 20ns -----------------------------------------------------------------------------------------------------------------------

−8V to 38V

UGATEx to PHASEx

 

DC -----------------------------------------------------------------------------------------------------------------------------

−0.3V to 6V

< 20ns -----------------------------------------------------------------------------------------------------------------------

−5V to 7.5V

LGATEx to GND

 

DC -----------------------------------------------------------------------------------------------------------------------------

−0.3V to 6V

< 20ns -----------------------------------------------------------------------------------------------------------------------

−2.5V to 7.5V

Power Dissipation, PD @ TA = 25°C

 

WQFN-20L 3x3 ------------------------------------------------------------------------------------------------------------

3.33W

Package Thermal Resistance (Note 2)

 

WQFN-20L 3x3, θJA -------------------------------------------------------------------------------------------------------

30°C/W

WQFN-20L 3x3, θJC ------------------------------------------------------------------------------------------------------

7.5°C/W

Lead Temperature (Soldering, 10 sec.) -------------------------------------------------------------------------------

260°C

Junction Temperature -----------------------------------------------------------------------------------------------------

150°C

Storage Temperature Range --------------------------------------------------------------------------------------------

−65°C to 150°C

ESD Susceptibility (Note 3)

 

HBM (Human Body Model) ----------------------------------------------------------------------------------------------

2kV

Recommended Operating Conditions (Note 4)

 

Supply Input Voltage, VIN -----------------------------------------------------------------------------------------------

5.5V to 25V

Junction Temperature Range --------------------------------------------------------------------------------------------

−40°C to 125°C

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

−40°C to 85°C

Copyright ©2014 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

DS8243A/B/C-07 November 2014

www.richtek.com

 

7

RT8243A/B/C

Electrical Characteristics

(VIN = 12V, VENLDO = 5V, VENTRIPx = 2V, VBYP1 = 5V, No Load on LDO5, LDO3, TA = 25°C, unless otherwise specified)

Parameter

Symbol

Test Conditions

Min

Typ

Max

Unit

Input Supply

 

 

 

 

 

 

 

 

 

VIN Power On Reset

 

Rising Threshold

--

5.1

5.5

V

 

 

 

 

 

 

 

 

Falling Threshold

3.5

--

4.5

 

 

 

 

VIN Shutdown Current

IVIN_SHDN

VENLDO = GND

 

--

20

40

 

 

 

 

 

 

 

 

 

 

A

VIN Standby Supply

IVIN_SBY

Both SMPS Off

 

--

250

350

Current

 

 

 

 

 

 

 

 

 

 

 

 

Quiescent Power

IQ

Both SMPSs on, FBx = 2.1V,

--

5

7

mW

Consumption

BYP1 = 5V, ENM = 3.3V (RT8243A)

 

 

 

 

 

 

SMPS Output and FB Voltage

 

 

 

 

 

 

 

 

FBx Regulation Voltage

VFBx

FBx, CCM Operation

--

2

--

V

FBx, DEM Operation

1.98

2.006

2.03

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Output Voltage

 

SMPS1, SMPS2

2

--

5.5

 

 

Adjustable Range

 

V

 

 

 

 

 

 

 

SECFB Voltage

VSECFB

RT8243B

 

1.92

2

2.08

 

 

On Time

 

 

 

 

 

 

 

 

 

ON-Time Pulse Width

tUGATEx

VIN = 20V

 

VPHASE1 = 2V

--

256

--

ns

RTON = 56k

 

VPHASE2 = 2V

--

220

--

 

 

 

 

 

Minimum Off-Time

tLGATEx

VFBx = 1.8V

 

--

--

400

ns

Frequency Range

fSMPS1

SMPS1 Operating Frequency

200

--

400

kHz

fSMPS2

SMPS2 Operating Frequency

233

--

466

 

 

 

Ultrasonic Mode

fASM

RT8243C, VPHASEx = 50mV

25

--

--

kHz

Frequency

 

 

 

 

 

 

 

 

 

Soft-Start

 

 

 

 

 

 

 

 

 

Soft-Start Time

tSSx

Zero to 200mV Current Limit Threshold

--

2

--

ms

from ENTRIPx Enable

 

 

 

 

 

 

 

Current Sense

 

 

 

 

 

 

 

 

 

Current Limit Current

IENTRIPx

VENTRIPx = 0.9V

9.4

10

10.6

A

Source

 

 

 

 

 

 

 

 

 

Temperature Coefficient

 

On The Basis of 25 C

--

4700

--

ppm/ C

of IENTRIPx

 

 

 

 

 

 

 

 

 

 

Current Limit Adjustment

 

VENTRIPx = IENTRIPx x RENTRIPx

0.5

--

2.7

V

Range

 

 

 

 

 

 

 

 

 

 

Current Limit Threshold

VENTRIPx

GND PHASEx, VENTRIPx = 2V

180

200

225

mV

Zero-Current Threshold

VZC

GND PHASEx, FBx = 2.1V

--

3

--

mV

Internal Regulator and Reference

 

 

 

 

 

 

 

 

 

 

VBYP1 = 0V, ILDO5 < 100mA

4.9

5

5.1

 

 

LDO5 Output Voltage

VLDO5

VBYP1 = 0V, ILDO5 < 100mA ,

4.75

--

5.25

V

6.5V < VIN < 25V

 

 

 

 

 

VBYP1 = 0V, ILDO5 < 50mA,

4.75

--

5.25

 

 

 

 

5.5V < VIN < 25V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Copyright ©2014 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

www.richtek.com

DS8243A/B/C-07 November 2014

8

 

+ 17 hidden pages