Richtek RT9728CHGE, RT9728CHGQW Schematic [ru]

Download

RT9728C

120m

ΩΩ

Ω, 1.3A Power Switch with Programmable Current Limit

ΩΩ

General Description

The RT9728C is a cost effective, low voltage, single

P-MOSFET high-side power switch IC for USB application

with a programmable current limit feature. Low switch-on

resistance (typ.120mΩ) and low supply current (typ.

120μA) are realized in this IC.The RT9728C can offer a

programmable current limit threshold between 75mA and

1.3A (typ.) via an external resistor. The ±10% current limit

accuracy can be realized for all current limit settings. In

addition, a flag output is available to indicate fault

conditions to the local USB controller. Furthermore, the

chip also integrates an embedded delay function to prevent

mis-operation from happening due to high inrush current.

The RT9728C is an ideal solution for USB power supply

and can support flexible applications since it is functional

for various current limit requirements. It is available in

SOT-23-6 and WDFN-6L 2x2 packages.

Features

±±





±10% Current Limit Accuracy @ 1.3A



±±



 Adjustable Current Limit : 75mA to 1.3A (typ.)



 Meets USB Current Limiting Requirements



 Operating Voltage Range : 2.5V to 5.5V



 Reverse Input



 Built-in Soft-Start



 120m



 120



 RoHS Compliant and Halogen Free



ΩΩ

Ω High-Side MOSFET

ΩΩ

μμ

μA Supply Current

μμ

−−

−Output Voltage Protection

−−

Applications

 USB Bus/Self Powered Hubs

 USB Peripheral Ports

 ACPI Power Distribution

 Battery Power Equipment

 3G/3.5G Data Card, Set-Top Boxes

Ordering Information

RT9728C

Package Type E : SOT-23-6 QW : WDFN-6L 2x2

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

H : Chip Enable High

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.

Pin Configurations

(TOP VIEW)

ILIM

VOUT

GND

VIN

SOT-23-6

VOUT

ILIM

WDFN-6L 2x2

FAULT

GND

VIN

GND ENFAULT

DS9728C-00 October 2015 www.richtek.com

RT9728C

Marking Information

RT9728CHGE

42= : Product Code

42=DNN

Typical Application Circuit

DNN : Date Code

RT9728CHGQW

3WW

3W : Product Code

W : Date Code

FAULT Signal

Chip Enable

FAULT

100k

10µF

VIN

FAULT

VOUT

RT9728C

Functional Pin Description

Pin No.

SOT-23-6 WDFN-6L 2x2

1 6 VIN Input Voltage.

7 (Exposed Pad)

3 4 EN Chip Enable.

4 3

5 2 ILIM

6 1

Pin Name Pin Function

GND

FAULT

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

Active-Low Open-Drain Output. Asserted during over current, over temperature, or reverse-voltage conditions.

Current Limit Set Pin. External resistor used to set current limit threshold. Recommend 19.1k  R

VOUT Power Switch Output.

ILIM

GND

OUT

150µF

ILIM

 232k.

ILIM

DS9728C-00 October 2015www.richtek.com

Function Block Diagram

VIN

Switch

well

Current

Sense

RT9728C

Reverse Voltage

Comparator

VOUT

UVLO

Drive

Thermal

Sense

Operation

The RT9728C are current-limited, power-distribution

switches using P-channel MOSFETs for applications

where short circuits or heavy capacitive loads will be

encountered. These devices allow the user to program

the current-limit threshold between 75mA and 1.3A (typ)

via an external resistor. Additional device shutdown features

include over temperature protection and reverse-voltage

protection.

Current

Limit

ILIM

4ms

Deglitch

7.5ms

Deglitch

≒60

FAULT

GND

The driver controls the gate voltage of the power switch.

The driver incorporates circuitry that controls the rise and

fall times of the output voltage to limit large current and

voltage surges and provides built-in soft-start functionality.

The RT9728C enters the constant-current mode when the

load exceeds the current-limit threshold.

DS9728C-00 October 2015 www.richtek.com

RT9728C

Absolute Maximum Ratings (Note 1)

 Supply Input Voltage ------------------------------------------------------------------------------------------------------ −0.3V to 6V

 Other Pin Voltage --------------------------------------------------------------------------------------------------------- −0.3V to 6V

 Power Dissipation, P

SOT-23-6 -------------------------------------------------------------------------------------------------------------------- 0.4W

WDFN-6L 2x2 -------------------------------------------------------------------------------------------------------------- 0.606W

 Package Thermal Resistance (Note 2)

SOT-23-6, θJA--------------------------------------------------------------------------------------------------------------- 250°C/W

WDFN-6L 2x2, θJA--------------------------------------------------------------------------------------------------------- 165°C/W

WDFN-6L 2x2, θJC-------------------------------------------------------------------------------------------------------- 7°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)

@ T

= 25°C

 Supply Input Voltage, VIN ----------------------------------------------------------------------------------------------- 2.5V to 5.5V

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

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

Electrical Characteristics

(VIN = 3.6V, 19.1kΩ ≤ R

Parameter Symbol Test Conditions Min Typ Max Unit

EN Input Voltage

Current Limit Threshold Resistor Range

Under Voltage Lockout Threshold

Shutdown Current I

Quiescent Current IQ

Reverse Leakage Current I

Thermal Shutdown Temperature Static Drain-Source On-State Resistance

Current Limit I

≤ 232kΩ, T

ILIM

Logic-High V

= 25°C, unless otherwise specified)

1.1 -- --

Logic- Low VIL -- -- 0.66

(nominal 1%) from I

ILIM

Rising -- 2.3 --

UVLO

SHDN

REV

-- 160 -- °C

DS(ON)

LIM

VIN Falling -- 2.1 --

VIN = 5.5V, No Load on V

= 5.5V,

No Load on V

= 5.5V, VIN = 0V -- 1 3 A

OUT

ISW = 0.2A -- 120 -- m

= 20k 1190 1295 1400

ILIM

= 49.9k 468 520 572

ILIM

= 210k 110 130 150

ILIM

to GND 19.1 -- 232 k

LIM

, VEN = 0V -- 1 3 A

OUT

= 20k -- 120 170

ILIM

= 210k -- 120 170

ILIM

A

ILIM Shorted to VIN 50 75 100

DS9728C-00 October 2015www.richtek.com

RT9728C

Parameter Symbol Test Conditions Min Typ Max Unit

Reverse Voltage Comparator Trip Point (V

OUT

VIN)

FAULT Output Low Voltage

FAULT Off State Leakage

FAULT Deglitch

Note 1. Stresses beyond those listed “Absolute Maximum Ratings” may cause permanent damage to the device. These are

stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in

the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may

affect device reliability.

Note 2. θ

Note 3. Devices are ESD sensitive. Handling precaution is recommended. Note 4. The device is not guaranteed to function outside its operating conditions.

is measured at T

measured at the exposed pad of the package.

-- 135 -- mV

= 1mA

= 25°C on a low effective thermal conductivity single-layer test board per JEDEC 51-3. θJC is

FAULT

= 5.5V

FAULT assertion or de-assertion due to over current condition

FAULT assertion or de-assertion due to reverse voltage condition

-- 180 -- mV

-- 1 -- A

5 7.5 10

2 4 6

DS9728C-00 October 2015 www.richtek.com

RT9728C

)

Typical Operating Characteristics

Supply Current vs. Temperature

150

140

130

120

110

100

Supply Current (μA

-50 -25 0 25 50 75 100 125

Temperature (°C)

On- Resistance vs. Temperature

150

140

130

120

110

100

On-Resistance (m )

-50-25 0 255075100125

VIN = 3.6V

VIN = 5V

Temperature (°C)

Fault Deglitch Timing vs. Temperature

Fault Deglitch Timing (ms

-50 -25 0 25 50 75 100 125

Temperature (°C)

Current Limit vs. Te m perature

1.6

1.5

1.4

1.3

Current Limit (A)

1.2

1.1

-50 -25 0 25 50 75 100 125

Temp erature (°C)

ILIM

= 20kΩ

EN Threshold Voltage vs. Temperature

1.5

1.4

1.3

1.2

1.1

1.0

0.9

0.8

0.7

EN Threshold Voltage (V) 1

0.6

0.5

-50 -25 0 25 50 75 100 125

Temperature (°C)

Rising

Falling

Under Voltage Lockout vs. Temperature

3.0

2.8

2.6

2.4

2.2

2.0

1.8

1.6

1.4

Under Voltage Lockout (V

1.2

1.0

-50 -25 0 25 50 75 100 125

Temperature (°C)

Rising

Falling

DS9728C-00 October 2015www.richtek.com

RT9728C

(10V/Div)

OUT

(5V/Div)

(1A/Div)

OUT

(2V/Div)

Fault

(5V/Div)

(1A/Div)

Power On from EN

RT9728C, VIN = 5V, C R

= 20kΩ, R

ILIM

OUT

= 5Ω

Time (500μs/Div)

Current Limit

Full Load (5Ω) to Short Circuit

VIN = 5V, C R

= 20kΩ

ILIM

OUT

= 150μF,

(10V/Div)

OUT

(5V/Div)

(1A/Div)

OUT

(2V/Div)

Fault

(5V/Div)

(1A/Div)

Power Off from EN

RT9728C, VIN = 5V, C R

= 20kΩ, R

ILIM

OUT

= 5Ω

Time (500μs/Div)

Current Limit

Short Circuit to Full Load (5Ω)

VIN = 5V, C R

= 20kΩ

ILIM

= 150μF,

OUT

= 150μF,

OUT

Time (2.5ms/Div)

Current Limit

Short Circuit to No Load VIN = 5V, C

= 20kΩ

ILIM

= 150μF,

OUT

(2V/Div)

Time (2.5ms/Div)

Current Limit

No Load to Short Circuit

VIN = 5V, C R

= 20kΩ

ILIM

= 150μF,

OUT

(2V/Div)

Fault

(5V/Div)

(1A/Div)

Time (2.5ms/Div)

(1A/Div)

Time (2.5ms/Div)

DS9728C-00 October 2015 www.richtek.com

RT9728C

Static Drain-Source Current vs. V

1600

1400

1200

1000

800

600

400

200

Static Drain-Source Current (mA)1

0 200 400 600 800 1000

VIN - V

VIN = 5.5V, R

(mV)

OUT

ILIM

- V

= 20kΩ

OUT

Static Drain-Source Current vs. V

160

140

120

100

Static Drain-Source Current (mA) 1

0 200 400 600 800 1000

VIN - V

VIN = 5.5V, R

(mV)

OUT

ILIM

- V

= 200kΩ

OUT

DS9728C-00 October 2015www.richtek.com

Applications Information

)

RT9728C

The RT9728C is a single P-MOSFET high-side power

switch with active-high/low enable input, optimized for self-

powered and bus-powered Universal Serial Bus (USB)

applications. The switch's low R

meets USB voltage

DS(ON)

drop requirements and a flag output is available to indicate

fault conditions to the local USB controller.

Current Limiting and Short Circuit Protection

When a heavy load or short circuit situation occurs while

the switch is enabled, large transient current may flow

through the device. The RT9728C includes a current-limit

circuitry to prevent these large currents from damaging

the MOSFET switch and the hub downstream ports. The

RT9728C provides an adjustable current limit threshold

between 120mA and 1.3A (typ) via an external resistor,

, between 19.1kΩ and 232kΩ. However, if the ILIM

ILIM

pin is connected to VIN, the current limit threshold will be

75mA (typ). Once the current limit threshold is exceeded,

the device enters constant-current mode until either

thermal shutdown occurs or the fault is removed. The

table1 shows a recommended current limit value vs. R

resistor.

1600

1400

1200

1000

800

600

400

200

Current Limit Threshold (mA

Current Limit Threshold vs. R

20 50 80 110 140 170 200 230

(k )

ILIM

Figure 1. Current Limit Threshold vs R

ILIM

Desired Nominal

Current Limit

(mA)

Table 1. Recommended R

Ide al R esi sto r

(k)

Closet 1%

Resistor (k)

Resistor Selections

ILIM

Actual Limits (Include R Tolerance)

IOS Min (mA) I OS Nom (m A) IOS Max (mA )

75 Short ILI M to VIN 50.0 75.0 100.0

120 226. 1 22 6.0 101. 3 120 .0 142.1

200 134. 0 13 3.0 173. 7 201 .5 233.9

300 88.5 88.7 262. 1 299.4 342.3

400 65.9 66.5 351. 1 396.7 448.7

500 52.5 52.3 443. 9 501.6 562.4

600 43.5 43.2 535. 1 604.6 674.1

700 37.2 37.4 616. 0 696.0 776.0

800 32.4 32.4 708. 7 800.8 892.9

900 28.7 28.7 797. 8 901 .5 1005. 2

1000 25.8 26.1 875. 4 989.1 1102.8

1100 2 3.4 23.2 982. 1 1109.7 1237.3

1200 2 1.4 21.5 1057.9 11 95. 4 13 32. 9

1300 1 9.7 19.6 1178.0 1308.5 1439.0

DS9728C-00 October 2015 www.richtek.com

RT9728C

Fault Flag

The RT9728C provides a FAULT signal pin which is an N-

channel open drain MOSFET output. This open drain output

goes low when current exceeds current limit threshold,

− VIN exceeds reverse voltage trip level, or the die

OUT

temperature exceeds 160°C approximately. The FAULT

output is capable of sinking a 1mA load to typically 180mV

above ground. The FAULT pin requires a pull-up resistor;

this resistor should be large in value to reduce energy

drain. A 100kΩ pull-up resistor works well for most

applications. In case of an over current condition, FAULT

will be asserted only after the flag response delay time,

tD, has elapsed. This ensures that FAULT is asserted upon

valid over current conditions and that erroneous error

reporting is eliminated. For example, false over current

conditions may occur during hot-plug events when

extremely large capacitive loads are connected, which

induces a high transient inrush current that exceeds the

current limit threshold. The FAULT response delay time,

tD, is typically 7.5ms.

Supply Filter/Bypass Ca pa citor

A 10μF low ESR ceramic capacitor connected from VIN to

GND and located close to the device is strongly

recommended to prevent input voltage drooping during hot-

plug events. However, higher capacitor values may be used

to further reduce the voltage droop on the input. Without

this bypass capacitor, an output short may cause sufficient

ringing on the input (from source lead inductance) to

destroy the internal control circuitry. Note that the input

transient voltage must never exceed 6V as stated in the

Absolute Maximum Ratings.

Output Filter Capacitor

A low ESR 150μF aluminum electrolytic capacitor

connected between V

recommended to meet the USB standard maximum droop

requirement for the hub, VBUS. Standard bypass methods

should be used to minimize inductance and resistance

between the bypass capacitor and the downstream

connector to reduce EMI and decouple voltage droop

caused by hot-insertion transients in downstream cables.

Ferrite beads in series with VBUS, the ground line and

the 0.1μF bypass capacitors at the power connector pins

and GND is strongly

OUT

are recommended for EMI and ESD protection. The bypass

capacitor itself should have a low dissipation factor to allow

decoupling at higher frequencies.

Chip Enable Input

The RT9728C will be disabled when the EN pin is in a

logic-low/high condition. During this condition, the internal

circuitry and MOSFET are turned off, reducing the supply

current to 1μA typical. The maximum guaranteed voltage

for a logic-low at the EN pin is 0.66V. A minimum

guaranteed voltage of 1.1V at the EN pin will turn off the

RT9728C. Floating the input may cause unpredictable

operation. EN should not be allowed to go negative with

respect to GND.

Under Voltage Lockout

Under voltage lockout (UVLO) prevents the MOSFET

switch from turning on until input voltage exceeds

approximately 2.3V. If input voltage drops below

approximately 2.1V, UVLO turns off the MOSFET switch

and FAULT will be asserted accordingly. The under voltage

lockout detection functions only when the switch is

enabled.

Thermal Considerations

For continuous operation, do not exceed absolute

maximum junction temperature. The maximum power

dissipation depends on the thermal resistance of the IC

package, PCB layout, rate of surrounding airflow, and

difference between junction and ambient temperature. The

maximum power dissipation can be calculated by the

following formula :

where T

the ambient temperature, and θ

D(MAX)

= (T

J(MAX)

− TA) / θ

J(MAX)

is the maximum junction temperature, TA is

is the junction to ambient

thermal resistance.

For recommended operating condition specifications, the

maximum junction temperature is 125°C. The junction to

ambient thermal resistance, θJA, is layout dependent. For

SOT-23-6 packages, the thermal resistance, θJA, is 250°C/

W on a standard JEDEC 51-3 single-layer thermal test

board. For WDFN-6L 2x2 packages, the thermal

resistance, θJA, is 165°C/W on a standard JEDEC 51-3

DS9728C-00 October 2015www.richtek.com

single-layer thermal test board. The maximum power

dissipation at TA = 25°C can be calculated by the following

formula :

RT9728C

= (125°C − 25°C) / (250°C/W) = 0.4W for

D(MAX)

SOT-23-6 package

= (125°C − 25°C) / (165°C/W) = 0.606W for

D(MAX)

WDFN-6L 2x2 package

The maximum power dissipation depends on the operating

ambient temperature for fixed T

and thermal

J(MAX)

resistance, θJA. The derating curves in Figure 2 allow the

designer to see the effect of rising ambient temperature

on the maximum power dissipation.

0.65

0.60

0.55

0.50

0.45

0.40

0.35

0.30

0.25

0.20

0.15

0.10

0.05

Maximum Power Dissipation (W) 1

0.00 0 25 50 75 100 125

SOT-23-6

WDFN-6L 2x2

Ambient Temperature (°C)

Single-Layer PCB

Figure 2. Derating Curve of Maximum Power Dissipation

DS9728C-00 October 2015 www.richtek.com

RT9728C

Outline Dimension

Dimensions In Millimeters Dimensions In Inches

Symbol

Min Max Min Max

A 0.889 1.295 0.031 0.051

A1 0.000 0.152 0.000 0.006

B 1.397 1.803 0.055 0.071

b 0.250 0.560 0.010 0.022

C 2.591 2.997 0.102 0.118

D 2.692 3.099 0.106 0.122

e 0.838 1.041 0.033 0.041

H 0.080 0.254 0.003 0.010

L 0.300 0.610 0.012 0.024

SOT-23-6 Surface Mount Package

DS9728C-00 October 2015www.richtek.com

RT9728C

SEE DETAIL A

DETAIL A

Pin #1 ID and Tie Bar Mark Options

Note : The configuration of the Pin #1 identifier is optional,

but must be located within the zone indicated.

Dimensions In Millimeters Dimensions In Inches

Symbol

Min Max Min Max

A 0.700 0.800 0.028 0.031

A1 0.000 0.050 0.000 0.002

A3 0.175 0.250

b 0.200 0.350 0.008 0.014

D 1.950 2.050 0.077 0.081

D2 1.000 1.450 0.039 0.057

E 1.950 2.050 0.077 0.081

E2 0.500 0.850 0.020 0.033

e 0.650 0.026

L 0.300 0.400

Richtek Technology Corporation

14F, No. 8, Tai Yuen 1st Street, Chupei City

Hsinchu, Taiwan, R.O.C.

Tel: (8863)5526789

0.007 0.010

0.012 0.016

W-Type 6L DFN 2x2 Package

Richtek products are sold by description only. Richtek reserves the right to change the circuitry and/or specifications without notice at any time. Customers should

obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete. Richtek cannot

assume responsibility for use of any circuitry other than circuitry entirely embodied in a Richtek product. Information furnished by Richtek is believed to be

accurate and reliable. However, no responsibility is assumed by Richtek or its subsidiaries for its use; nor for any infringements of patents or other rights of third

parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Richtek or its subsidiaries.

DS9728C-00 October 2015 www.richtek.com

Richtek RT9728CHGE, RT9728CHGQW Schematic [ru]

Specifications and Main Features

Frequently Asked Questions

User Manual