RT9728AHZQW - Richtek Technology

RT9728A

DS9728A-08 November 2018 www.richtek.com

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.

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−−

−−

−Output Voltage Protection



Built-in Soft-Start



120mΩΩ

ΩΩ

Ω High-Side MOSFET



120μμ

μμ

μA Supply Current



RoHS Compliant and Halogen Free

120mΩΩ

ΩΩ

Ω, 1.3A Power Switch with Programmable Current Limit

General Description

The RT9728A 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 RT9728A 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 RT9728A 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.

Pin Configuration

(TOP VIEW)

SOT-23-6

Applications

USB Bus/Self Powered Hubs

USB Peripheral Ports

ACPI Power Distribution

Battery Power Equipment

3G/3.5G Data Card, Set-Top Boxes

VOUT ILIM

VIN GND

FAULT

EN/EN

VOUT

ILIM

VIN

GND

7EN/ENFAULT

WDFN-6L 2x2

RT9728A

Package Type

E : SOT-23-6

QW : WDFN-6L 2x2

H : Chip Enable High

L : Chip Enable Low

Lead Plating System

G : Green (Halogen Free and Pb Free)

Z : ECO (Ecological Element with

Halogen Free and Pb free)

RT9728A

DS9728A-08 November 2018www.richtek.com

Pin No. Pin Na m e Pin Function

SOT-23-6 WDFN-6L 2x2

1 6 VIN Input voltage.

2 5,

7 (Exposed Pad) GND Ground. The exposed pad must be soldered to a large PCB and

connected to GND for maximum power dissipation.

3 4

EN/EN Chip enable.

4 3

FAULT Active-low open-drain output. Asserted during over current, over

temperature, or reverse-voltage conditions.

5 2 ILIM

Current limit set pin. External resistor used to set current limit

threshold. Recommend 19.1k  RILIM  232k.

6 1

VOUT Power switch output.

Functional Pin Description

Typical Application Circuit

VIN

RT9728A

VIN

ILIM

RILIM

VOUT

150µF

FAULT

EN/EN

RFAULT

CIN

VOUT

GND

FAULT Signal

100k

10µF

Chip Enable

Marking Information

19 : Product Code

W : Date Code

RT9728ALGQW

02=DNN

RT9728ALGE

02= : Product Code

DNN : Date Code

01=DNN

01= : Product Code

DNN : Date Code

RT9728AHGE

17 : Product Code

W : Date Code

RT9728AHGQW

19W17W

17 : Product Code

W : Date Code

RT9728AHZQW

19 : Product Code

W : Date Code

RT9728ALZQW

19W17W

RT9728A

DS9728A-08 November 2018 www.richtek.com

Functional Block Diagram

UVLO

Current

Limit

7.5ms

Deglitch

4ms

Deglitch

Thermal

Sense

Drive

Reverse Voltage

Comparator

Switch

well

Current

Sense

VOUT

ILIM

GND

EN/EN

VIN

FAULT

≒14

RT9728A

DS9728A-08 November 2018www.richtek.com

Electrical Characteristics

(VIN = 3.6V, 19.1kΩ RILIM 232kΩ, TA = 25°C, unless otherwise specified)

Parameter Symbol Test Conditions Min Typ Max Unit

EN Input Voltage

Logic-High VIH 1.1 -- --

Logic- Low VIL -- -- 0.66

Current Limit Threshold

Resistor Range RILIM (nominal 1%) from ILIM to GND 19.1 -- 232 k

Under Voltage Lockout

Threshold VUVLO VIN rising -- 2.3 -- V

VIN falling -- 2.1 --

Shutdown Current ISHDN V

IN = 5.5V, no load on VOUT, VEN = 0V -- 1 3 A

Quiescent Current IQ VIN = 5.5V,

no load on VOUT

RILIM = 20k -- 120 170

A

RILIM = 210k -- 120 170

Reverse Leakage Current IREV V

OUT = 5.5V, VIN = 0V -- 1 3 A

Thermal Shutdown

Temperature TSD -- 160 -- °C

Static Drain-Source On-State

Resistance RDS(ON) I

SW = 0.2A -- 120 -- m

Current Limit ILIM

RILIM = 20k 1190 1295 1400

RILIM = 49.9k 468 520 572

RILIM = 210k 110 130 150

ILIM shorted to VIN 50 75 100

Absolute Maximum Ratings (Note 1)

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

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

Power Dissipation, PD @ TA = 25°C

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)

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



RT9728A

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Parameter Symbol Test Conditions Min Typ Max Unit

Reverse Voltage Comparator

Trip Point (VOUT VIN) -- 135 -- mV

FAULT Output Low Voltage VOL IFAULT = 1mA -- 180 -- mV

FAULT Off State Leakage VFAULT = 5.5V -- 1 -- A

FAULT Deglitch

FAULT assertion or de-assertion due to

over current condition 5 7.5 10

FAULT assertion or de-assertion due to

reverse voltage condition 2 4 6

Note 1. Stresses beyond those listed under “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. θJA is measured at TA = 25°C on a low effective thermal conductivity single-layer test board per JEDEC 51-3. θJC is

measured at the exposed pad of the package.

Note 3. Devices are ESD sensitive. Handling precaution is recommended.

Note 4. The device is not guaranteed to function outside its operating conditions.

RT9728A

DS9728A-08 November 2018www.richtek.com

Typical Operating Characteristics

Supply Current vs. Temperature

100

110

120

130

140

150

-50 -25 0 25 50 75 100 125

Temperature (°C)

Supply Current (μA

)

Fault Deglitch Timing vs. Temperature

-50 -25 0 25 50 75 100 125

Temperature (°C)

Fault Deglitch Timing (ms

)

Under Voltage Lock out vs. Tem pe rature

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

3.0

-50 -25 0 25 50 75 100 125

Temperature (°C)

Under Voltage Lockout (V

)

Rising

Falling

EN/EN Threshold Voltage vs. Tem perature

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

1.5

-50 -25 0 25 50 75 100 125

Temperature (°C)

EN/EN Threshold Voltage (V) 1

Rising

Falling

On- Resistance v s. Temperature

100

110

120

130

140

150

-50-25 0 255075100125

Temperature (°C)

On-Resistance (m )

VIN = 3.6V

VIN = 5V

Current Lim it vs. Tempe rature

1.1

1.2

1.3

1.4

1.5

1.6

-50 -25 0 25 50 75 100 125

Temperature (°C)

Current Limit (A)

RILIM = 20kΩ

RT9728A

DS9728A-08 November 2018 www.richtek.com

Current Limit

Time (2.5ms/Div)

Short Circuit to Full Load (5Ω)

VOUT

(2V/Div)

Fault

(5V/Div)

IIN

(1A/Div)

VIN = 5V, COUT = 150μF,

RILIM = 20kΩ

VOUT

(2V/Div)

Fault

(5V/Div)

IIN

(1A/Div)

Current Limit

Time (2.5ms/Div)

VIN = 5V, COUT = 150μF,

RILIM = 20kΩ

Full Load (5Ω) to Short Circuit

Power On from EN

Time (500μs/Div)

VOUT

(5V/Div)

VEN

(10V/Div)

IIN

(1A/Div)

RT9728AH, VIN = 5V, COUT = 150μF,

RILIM = 20kΩ, ROUT = 5Ω

Power Off from EN

Time (500μs/Div)

VOUT

(5V/Div)

VEN

(10V/Div)

IIN

(1A/Div)

RT9728AH, VIN = 5V, COUT = 150μF,

RILIM = 20kΩ, ROUT = 5Ω

Power Off from EN

Time (500μs/Div)

VOUT

(5V/Div)

VEN

(10V/Div)

IIN

(1A/Div)

RT9728AL, VIN = 5V, COUT = 150μF,

RILIM = 20kΩ, ROUT = 5Ω

Power On from EN

Time (500μs/Div)

VOUT

(5V/Div)

VEN

(10V/Div)

IIN

(1A/Div)

RT9728AL, VIN = 5V, COUT = 150μF,

RILIM = 20kΩ, ROUT = 5Ω

RT9728A

DS9728A-08 November 2018www.richtek.com

Static Drain-Source Current vs. VIN - VOUT

100

120

140

160

0 200 400 600 800 1000

VIN - VOUT (mV)

Static Drain-Source Current (mA) 1

VIN = 5.5V, RILIM = 200kΩ

Static Drain-Source Current vs. VIN - VOUT

200

400

600

800

1000

1200

1400

1600

0 200 400 600 800 1000

VIN - VOUT (mV)

Static Drain-Source Current (mA)1

VIN = 5.5V, RILIM = 20kΩ

Current Limit

Time (2.5ms/Div)

No Load to Short Circuit

VOUT

(2V/Div)

Fault

(5V/Div)

IIN

(1A/Div)

VIN = 5V, COUT = 150μF,

RILIM = 20kΩ

Current Limit

Short Circuit to No Load

VOUT

(2V/Div)

Fault

(5V/Div)

IIN

(1A/Div)

VIN = 5V, COUT = 150μF,

RILIM = 20kΩ

Time (2.5ms/Div)

RT9728A

DS9728A-08 November 2018 www.richtek.com

Applications Information

The RT9728A 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 RDS(ON) meets USB voltage

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 RT9728A includes a current-limit

circuitry to prevent these large currents from damaging

the MOSFET switch and the hub downstream ports. The

RT9728A provides an adjustable current limit threshold

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

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

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

75mA (typ). Once the current limit threshold is exceeded, Figure 1. Current Limit Threshold vs RILIM

Current Limit Threshold vs. RILIM

200

400

600

800

1000

1200

1400

1600

20 50 80 110 140 170 200 230

RILIM (k )

Current Limit Threshold (mA

)

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. RILIM

resistor.

Table 1. Recommended RILIM Resistor Selections

Des ired Nomina l

Current Limit

(mA)

Ideal Resist or

(k) Closet 1%

Resisto r (k )

Actual Limits (Include R Tolerance)

IOS M in (mA) I OS Nom (m A) IOS Max (mA)

75 Short ILIM to VIN 50.0 75.0 100.0

120 226.1 226.0 101.3 120.0 142.1

200 134.0 133.0 173.7 201.5 233.9

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 23.4 23.2 982.1 1109.7 1237.3

1200 21.4 21.5 1057.9 1195.4 1332.9

1300 19.7 19.6 1178.0 1308.5 1439.0

RT9728A

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Chip Enable Input

The RT9728AH/L will be disabled when the EN/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/EN pin is

0.66V. A minimum guaranteed voltage of 1.1V at the EN/

EN pin will turn off the RT9728A. Floating the input may

cause unpredictable operation. EN/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.

Fault Flag

The RT9728A 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,

VOUT − VIN exceeds reverse voltage trip level, or the die

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/Bypa ss 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 VOUT and GND is strongly

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

are recommended for EMI and ESD protection. The bypass

capacitor itself should have a low dissipation factor to allow

decoupling at higher frequencies.

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 :

PD(MAX) = (TJ(MAX) − TA) / θJA

where TJ(MAX) is the maximum junction temperature, TA is

the ambient temperature, and θJA 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

single-layer thermal test board. The maximum power

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

formula :

RT9728A

DS9728A-08 November 2018 www.richtek.com

Figure 2. Derating Curve of Maximum Power Dissipation

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

0.55

0.60

0.65

0 25 50 75 100 125

Ambient Temperature (°C)

Maximum Power Dissipation (W) 1

WDFN-6L 2x2

SOT-23-6

Single-Layer PCB

PD(MAX) = (125°C − 25°C) / (250°C/W) = 0.400W for

SOT-23-6 package

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

WDFN-6L 2x2 package

The maximum power dissipation depends on the operating

ambient temperature for fixed TJ(MAX) and thermal

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

designer to see the effect of rising ambient temperature

on the maximum power dissipation.

RT9728A

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Outline Dimension

AA1

SOT-23-6 Surface Mount Package

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

RT9728A

DS9728A-08 November 2018 www.richtek.com

Richtek Technology Corporation

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

Hsinchu, Taiwan, R.O.C.

Tel: (8863)5526789

Richtek products are sold by description only. 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.

Dimensions In Millimeters Dimensions In Inch es

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

0.007 0.010

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

0.012 0.016

W-Type 6L DFN 2x2 Package

SEE DETAIL A

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

but must be located within the zone indicated.

DETAIL A

Pin #1 ID and Tie Bar Mark Options