®
RT9742
70mΩ/55mΩ, 3A/2.5A/2A/1.5A/1A/0.5A High-Side Power
Ω
Ω
Switches with Flag
General Description
The RT9742 is a cost-effective, low-voltage, single
N-MOSFET high-side Power Switch IC for USB application.
Low switch-on resistance and low supply current are
realized in this IC.
The RT9742 integrates an over-current protection circuit,
a short fold back circuit, a thermal shutdown circuit and
an under-voltage lockout circuit for overall protection.
Besides, 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
miss-operation from happening due to inrush-current. The
RT9742 is an ideal solution for USB power supply and
can support flexible applications since it is available in
TSOT-23-5, TSOT-23-5 (FC) and SOT-23-3 package.
Features
70mΩ/55mΩ (typ.) N-MOSFET Switch
Ω
Ω
Operating Range : 2.7V to 6V
Reverse Blocking Current
Under Voltage Lockout
Deglitched Fault Report (FLG)
Thermal Protection with Fold-back
Over Current Protection
Short Circuit Protection
UL Approved
−
E219878
Nemko Approved-NO87949
Applications
USB Peripherals
Notebook PCs
Pin Configuration
(TOP VIEW)
VIN
5
2
EN/EN
4
3
VOUT
5
2
EN
4
3
VOUT
5
2
VIN
4
3
GND
3
2
VOUT GND FLG
VOUT GND VIN
EN GND FLG
VIN
VOUT
TSOT-23-5 /
TSOT-23-5 (FC)
TSOT-23-5
For RT9742M only
TSOT-23-5
For RT9742U only
SOT-23-3
Simplified Application Circuit
USB Controller
Supply Voltage
2.7V to 6V
C
IN
VIN
FLG
Over-Current
RT9742
Chip Enable
EN/EN
VOUT
+
C
OUT
V
BUS
D+
D-
GND
GND
Data
Copyright
©
2017 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9742-08
October 2017
www.richtek.com
1
RT9742
Ordering and Marking Information
Version
RT9742AGJ5F
RT9742BGJ5F
RT9742ANGJ5F
RT9742BNGJ5F
RT9742CGJ5F
RT9742DGJ5F
RT9742CNGJ5F
RT9742DNGJ5F
RT9742CGJ5
RT9742DGJ5
RT9742CNGJ5
RT9742DNGJ5
RT9742JNGV
RT9742EGJ5F
RT9742FGJ5F
RT9742ENGJ5F
RT9742FNGJ5F
RT9742EGJ5
RT9742FGJ5
RT9742ENGJ5
RT9742FNGJ5
RT9742KNGV
RT9742GGJ5F
RT9742HGJ5F
RT9742GNGJ5F
RT9742HNGJ5F
RT9742GGJ5
RT9742HGJ5
RT9742GNGJ5
RT9742HNGJ5
RT9742LNGV
RT9742MGJ5
RT9742MNGJ5
RT9742NGJ5F
RT9742PGJ5F
RT9742NNGJ5F
RT9742PNGJ5F
RT9742NGJ5
RT9742QGJ5
RT9742RGJ5
RT9742QNGJ5
RT9742RNGJ5
RT9742SNGV
RT9742UNGJ5
EN Function
Package
Discharge
Product
Current
Function Active Active Internal TSOT-23-5 TSOT-23-5 SOT-23-3
Code
High
Low Pull High
(FC)
07=
3A
Yes
V
V
06=
3A
Yes
V
V
0F=
3A
No
V
V
0E=
3A
No
V
V
05=
2A
Yes
V
V
04=
2A
Yes
V
V
0D=
2A
No
V
V
0C=
2A
No
V
V
0K=
2A
Yes
V
V
0J=
2A
Yes
V
V
11=
2A
No
V
V
10=
2A
No
V
V
6A=
2A
No
V
V
03=
1.5A
Yes
V
V
02=
1.5A
Yes
V
V
0B=
1.5A
No
V
V
0A=
1.5A
No
V
V
0H=
1.5A
Yes
V
V
0G=
1.5A
Yes
V
V
0Z=
1.5A
No
V
V
0Y=
1.5A
No
V
V
69=
1.5A
No
V
V
01=
1A
Yes
V
V
00=
1A
Yes
V
V
09=
1A
No
V
V
08=
1A
No
V
V
0F=
1A
Yes
V
V
0E=
1A
Yes
V
V
0X=
1A
No
V
V
0W=
1A
No
V
V
68=
1A
No
V
V
14=
1.5A
Yes
V
V
15=
1.5A
No
V
V
43=
2.5A
Yes
V
V
DD=
2.5A
Yes
V
V
42=
2.5A
No
V
V
CC=
2.5A
No
V
V
9H
2.5A
Yes
V
V
47=
0.5A
Yes
V
V
45=
0.5A
Yes
V
V
46=
0.5A
No
V
V
44=
0.5A
No
V
V
6V=
0.5A
No
V
V
9F=
1.5A
No
V
V
is a registered trademark of Richtek Technology Corporation.
Copyright
©
2017 Richtek Technology Corporation. All rights reserved.
www.richtek.com
2
DS9742-08
October 2017
RT9742
Note :
Richtek products are :
½
½
RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.
Suitable for use in SnPb or Pb-free soldering processes.
Functional Pin Description
Pin Name
VOUT
GND
FLG
Pin Function
Output voltage.
Ground.
Fault FLAG output.
Chip enable (Active High/Low).
Power input voltage.
EN/EN
VIN
Functional Block Diagram
TSOT-23-5 / TSOT-23-5 (FC) Package
VIN
EN/EN
Bias
UVLO
Current
Limiting
Gate
Control
Output Voltage
Detection
Thermal
Protection
Auto Discharge
FLG
Delay
GND
VOUT
Oscillator
Charge
Pump
SOT-23-3 Package
VIN
UVLO
Bias
Oscillator
Charge
Pump
Thermal
Protection
Gate
Control
Current
Limiting
Output Voltage
Detection
Auto
Discharge
VOUT
GND
Copyright
©
2017 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9742-08
October 2017
www.richtek.com
3
RT9742
TSOT-23-5 Package (For RT9742M Only)
VIN
EN
Bias
UVLO
Current
Limiting
Gate
Control
Oscillator
GND
Charge
Pump
Thermal
Protection
Output Voltage
Detector
Auto
Discharge
VOUT
VOUT
Operation
Charge Pump and Drivers
An internal charge pump supplies power to the driver circuit
and provides the necessary voltage to pull the gate of the
MOSFET above the source. The driver controls the gate
voltage of the power switch.
Current Limit
The RT9742 continuously monitors the output current for
over-current protection to protect the system power, the
power switch, and the load from damage during output
short circuit. When an overload or short circuit occurs,
the current-sense circuitry sends a control signal to the
driver. The driver reduces the gate voltage and drives the
power MOSFET into its saturation region, which switches
the output into a constant-current mode and holds the
current constant until the thermal shutdown occurs or the
fault is removed.
Under-Voltage Lockout
A voltage-sense circuit monitors the input voltage. When
the input voltage is above 2.4V, UVLO turns on the
MOSFET switch.
Thermal Shutdown
The RT9742 continuously monitors the operating
temperature of the power switch for over-temperature
protection. The RT9742 turns off the power switch to
prevent the device from damage if the junction temperature
rises to approximately 140°C due to over-current or short-
circuit conditions. The pass element turns on again after
the junction temperature cools to 120°C.
FLAG
The RT9742 pulls low the open drain output FLAG after
over current or over temperature condition occurring over
approximately 10ms.
Copyright
©
2017 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
4
DS9742-08
October 2017
RT9742
Absolute Maximum Ratings
(Note 1)
7V
−0.3V
to 7V
7V
0.49W
0.79W
0.41W
Supply Input Voltage, VIN -----------------------------------------------------------------------------------------------
EN Voltage ------------------------------------------------------------------------------------------------------------------
FLAG Voltage --------------------------------------------------------------------------------------------------------------
Power Dissipation, P
D
@ T
A
= 25°C
TSOT-23-5 -------------------------------------------------------------------------------------------------------------------
TSOT-23-5 (FC) ------------------------------------------------------------------------------------------------------------
SOT-23-3 --------------------------------------------------------------------------------------------------------------------
Package Thermal Resistance (Note 2)
TSOT-23-5,
θ
JA
------------------------------------------------------------------------------------------------------------- 203°C/W
TSOT-23-5 (FC),
θ
JA
------------------------------------------------------------------------------------------------------ 126.5°C/W
SOT-23-3,
θ
JA
--------------------------------------------------------------------------------------------------------------- 243.3°C/W
Junction Temperature ----------------------------------------------------------------------------------------------------- 150°C
Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------- 260°C
Storage Temperature Range --------------------------------------------------------------------------------------------
−65°C
to 150°C
ESD Susceptibility (Note 3)
HBM (Human Body Model) ---------------------------------------------------------------------------------------------- 2kV
Recommended Operating Conditions
(Note 4)
2.7V to 6V
0V to 6V
−40°C
to 125°C
−40°C
to 85°C
Supply Input Voltage, VIN -----------------------------------------------------------------------------------------------
EN Voltage ------------------------------------------------------------------------------------------------------------------
Junction Temperature Range --------------------------------------------------------------------------------------------
Ambient Temperature Range --------------------------------------------------------------------------------------------
Electrical Characteristics
Parameter
Input Quiescent Current
Input Shutdown Current
Switch On
Resistance
RT9742XXJ5F
RT9742XXJ5/V
RT9742Q/R/S
RT9742G/H/L
Over Current
Trip Threshold
(Note 5)
RT9742E/F/K/M/U
RT9742C/D/J
RT9742N/P
RT9742A/B
(V
IN
= 5V, C
IN
= 10μF, C
OUT
= 0.1μF, T
A
= 25°C, unless otherwise specified)
Symbol
I
Q
I
SHDN
R
DS(ON)
Test Conditions
Switch on, V
OUT
= open
V
IN
= 5V, no load on OUT, device
OFF, V
EN
= 0V or V
EN
= 5V
Min
--
--
--
--
0.65
1.05
1.55
2.05
2.55
3.05
Typ
30
0.1
55
70
0.89
1.4
2.1
2.8
3.5
4.2
Max
40
1
--
--
1
1.5
2.25
3
3.75
4.5
Unit
A
m
I
TRIP
V
IN
= 5V, 100A/s
A
Copyright
©
2017 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9742-08
October 2017
www.richtek.com
5
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