®
RT9728A
120mΩ, 1.3A Power Switch with Programmable Current Limit
Ω
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.
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
120mΩ High Side MOSFET
Ω
120μA Supply Current
μ
RoHS Compliant and Halogen Free
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
RT9728A
Package Type
E : SOT-23-6
QW : WDFN-6L 2x2
Lead Plating System
G : Green (Halogen Free and Pb Free)
Z : ECO (Ecological Element with
Halogen Free and Pb free)
H : Chip Enable High
L : Chip Enable Low
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)
VOUT ILIM FAULT
6
5
2
4
3
VIN GND EN/EN
SOT-23-6
ILIM
FAULT
GND
VOUT
1
2
3
6
5
4
VIN
GND
EN/EN
7
WDFN-6L 2x2
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9728A-03 July 2012
www.richtek.com
1
RT9728A
Marking Information
RT9728AHGE
01= : Product Code
RT9728ALGE
02= : Product Code
DNN : Date Code
01=DNN
02=DNN
DNN : Date Code
RT9728AHGQW
17 : Product Code
RT9728ALGQW
19 : Product Code
W : Date Code
17W
19W
W : Date Code
RT9728AHZQW
17 : Product Code
RT9728ALZQW
19 : Product Code
W : Date Code
17W
19W
W : Date Code
Typical Application Circuit
V
IN
R
FAULT
100k
FAULT Signal
Chip Enable
C
IN
10µF
VIN
VOUT
RT9728A
ILIM
GND
R
ILIM
V
OUT
150µF
FAULT
EN/EN
Functional Pin Description
Pin No.
SOT-23-6
WDFN-6L 2x2
1
6
5,
2
7 (Exposed Pad)
3
4
4
5
6
3
2
1
Pin Name
VIN
GND
EN/EN
FAULT
ILIM
VOUT
Pin Function
Input Voltage.
Ground. The exposed pad must be soldered to a large PCB and
connected to GND for maximum power dissipation.
Chip Enable.
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 19.1kΩ
≤
R
ILIM
≤
232kΩ.
Power Switch Output.
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
2
DS9728A-03 July 2012
RT9728A
Function Block Diagram
Reverse Voltage
Comparator
+
Switch
well
VIN
-
Current
Sense
4ms
Deglitch
Current
Limit
VOUT
EN/EN
Drive
FAULT
UVLO
Thermal
Sense
7.5ms
Deglitch
GND
ILIM
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9728A-03 July 2012
www.richtek.com
3
RT9728A
Absolute Maximum Ratings
(Note 1)
Supply Input Voltage ------------------------------------------------------------------------------------------------------
Other Pin Voltage ---------------------------------------------------------------------------------------------------------
Power Dissipation, P
D
@ T
A
= 25°C
SOT-23-6 --------------------------------------------------------------------------------------------------------------------
WDFN-6L 2x2 --------------------------------------------------------------------------------------------------------------
Package Thermal Resistance (Note 2)
SOT-23-6,
θ
JA
---------------------------------------------------------------------------------------------------------------
−
0.3V to 6V
−0.3V
to 6V
0.4W
0.606W
250°C/W
WDFN-6L 2x2,
θ
JA
--------------------------------------------------------------------------------------------------------- 165°C/W
WDFN-6L 2x2,
θ
JC
-------------------------------------------------------------------------------------------------------- 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
Electrical Characteristics
Parameter
Logic-High V
IH
Enable Input
Threshold Voltage Logic- Low V
IL
Current Limit Threshold
Resistor Range
Under Voltage Lockout
Threshold
Shutdown Current
Quiescent Current
Reverse Leakage Current
Thermal Shutdown
Temperature
Static Drain-Source On-State
Resistance
R
ILIM
(V
IN
= 3.6V, 19.1kΩ
≤
R
ILIM
≤
232kΩ, T
A
= 25°C, unless otherwise specified)
Symbol
Test Conditions
Min
1.1
--
Typ
--
--
--
2.3
2.1
1
120
120
1
160
120
1295
520
130
75
Max
--
0.66
232
--
--
3
170
170
3
--
--
1425
572
150
100
Unit
V
kΩ
V
μA
μA
μA
°C
mΩ
(nominal 1%) from I
LIM
to GND
V
IN
Rising
V
IN
Falling
V
IN
= 5.5V, No Load on V
OUT
, V
EN
= 0V
V
IN
= 5.5V,
No Load on V
OUT
V
OUT
= 5.5V, V
IN
= 0V
R
ILIM
= 20kΩ
R
ILIM
= 210kΩ
19.1
--
--
--
--
--
--
--
V
UVLO
I
SHDN
I
Q
I
REV
T
SD
R
DS(ON)
I
SW
= 0.2A
R
ILIM
= 20kΩ
--
1166
468
110
50
Current Limit
I
LIM
R
ILIM
= 49.9kΩ
R
ILIM
= 210kΩ
I
LIM
Shorted to V
IN
mA
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
4
DS9728A-03 July 2012
RT9728A
Parameter
Reverse Voltage Comparator
Trip Point (V
OUT
−
V
IN
)
FAULT Output Low Voltage
FAULT Off State Leakage
FAULT Deglitch
V
OL
I
FAULT
= 1mA
V
FAULT
= 5.5V
FAULT assertion or de-assertion due to
over current condition
FAULT assertion or de-assertion due to
reverse voltage condition
Symbol
Test Conditions
Min
--
--
--
5
2
Typ
135
180
1
7.5
4
Max
--
--
--
10
ms
6
Unit
mV
mV
μA
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
JA
is measured at T
A
= 25°C on a low effective thermal conductivity single-layer test board per JEDEC 51-3.
θ
JC
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.
Copyright
©
2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9728A-03 July 2012
www.richtek.com
5
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