®
RT9745A
Dual Channel, Low Resistance Load Switch
General Description
The RT9745A is a small, low R
ON
, dual channel load switch
with EN controlled pin. The product contains two N-
MOSFETs that can operate between an input voltage range
of 0.8V to 5.5V. Also, it supports a maximum continuous
current of 6A each channel. Each switch is independently
controlled by EN pins (EN1 and EN2), which can directly
interface with low-voltage control signals.
The RT9745A is available in the WDFN-14TL 3x2 package
with exposed pad for high power and heat dissipation.
Features
Integrated Dual Channel Load Switch
Input Voltage Range : 0.8V to 5.5V
Low R
ON
Resistance
½
R
ON
= 27mΩ at V
IN
= 5V (V
DD
= 5V)
Ω
½
½
R
ON
= 27mΩ at V
IN
= 3.6V (V
DD
= 5V)
Ω
Ω
R
ON
= 27mΩ at V
IN
= 1.8V (V
DD
= 5V)
6A Maximum Continuous Switch Current Per
Channel
Low Quiescent Current
½
75μA (Both Channels)
μ
½
Ordering Information
RT9745A
Package Type
QW : WDFN-14TL 3x2 (W-Type)
Lead Plating System
G : Green (Halogen Free and Pb Free)
55μA (Single Channel)
μ
Low Control Input Threshold Enables Use of 1.4V/
1.8V/2.5V/3.3V Logics
Configurable Rise Time
Quick Output Discharge (QOD)
Adaptive Discharge Current
14T-Lead WDFN Package with Thermal Pad
Note :
½
Richtek products are :
RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
½
Applications
Suitable for use in SnPb or Pb-free soldering processes.
Marking Information
0P : Product Code
0PW
W : Date Code
Ultrabook
TM
Notebooks/Netbooks
Tablet PC
Consumer Electronics
Set-Top Boxes/Residential Gateways
Telecom Systems
Solid State Drives (SSD)
Simplified Application Circuit
VIN1
C
IN1
Enable
Dual Power
Supply
or
Dual DC/DC
Converter
VOUT1
C
OUT1
SS1
C
SS1
SS2
C
SS2
VOUT2
GND
C
OUT2
R
L2
V
OUT2
R
L1
V
OUT1
RT9745A
EN1
VDD
Enable
C
IN2
EN2
VIN2
Copyright
©
2014 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9745A-00 August 2014
www.richtek.com
1
RT9745A
Pin Configurations
(TOP VIEW)
VIN1
VIN1
EN1
VDD
EN2
VIN2
VIN2
1
2
3
4
5
6
7
15
14
13
12
GND
11
10
9
8
VOUT1
VOUT1
SS1
GND
SS2
VOUT2
VOUT2
WDFN-14TL 3x2
Functional Pin Description
Pin No.
1, 2
3
4
5
6, 7
8, 9
10
11,
15 (Exposed Pad)
12
13, 14
Pin Name
VIN1
EN1
VDD
EN2
VIN2
VOUT2
SS2
GND
SS1
VOUT1
Pin Function
Input Voltage for Switch 1. Bypass this input with a ceramic capacitor to
GND. Recommended voltage range for this pin for optimal R
ON
performance
is 0.8V to V
DD
.
Enable Control Input for Switch 1 (Active High). Do not leave floating.
Charge Pump Voltage Input. Power supply to the device. Recommended
voltage range for this pin is 2.5V to 5.5V.
Enable Control Input for Switch 2 (Active High). Do not leave floating.
Input Voltage for Switch 2. Bypass this input with a ceramic capacitor to
GND. Recommended voltage range for this pin for optimal R
ON
performance
is 0.8V to V
DD
.
Switch 2 Output.
Switch 2 Slew Rate Control. Can be left floating.
Ground. The Exposed pad should be soldered to a large PCB and connected
to GND for maximum thermal dissipation.
Switch 1 Slew Rate Control. Can be left floating.
Switch 1 Output.
Copyright
©
2014 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
2
DS9745A-00 August 2014
RT9745A
Function Block Diagram
VIN1
SS1
EN1
Control Logic
VOUT1
VDD
Charge Pump
GND
VOUT2
EN2
SS2
VIN2
Control Logic
Operation
The RT9745A contains two N-MOSFETs which controlled
by EN pin independently.
Enable Control
Asserting ENx pin high enables the switch. Switch will
turn on as the EN signal is higher than V
ENH
, and turn off
when the EN signal is lower than V
ENL
. Thus, it can operate
under low voltage logic, please refer to the electrical
characteristics. This pin cannot be left floating and must
be tied either high or low voltage for proper functionality.
Charge Pump
Provides sufficient bias voltage to both N-MOSFETs.
Adjustable Rise Time
Connecting a capacitor to GND on the SSx pin sets the
slew rate for each channel. It could also be used to prevent
in-rush current.
Copyright
©
2014 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9745A-00 August 2014
www.richtek.com
3
RT9745A
Absolute Maximum Ratings
(Note 1)
VIN1, VIN2, EN1, EN2, VDD, VOUT1, VOUT2, SS1, SS2 -------------------------------------------------------
−0.3V
to 6V
Maximum Continuous Switch Current Per Channel, IMAX ------------------------------------------------------- 6A
Maximum Pulsed Switch Current, Pulse <300μs, 2% Duty Cycle Per Channel, IPLS -------------------- 8A
Power Dissipation, P
D
@ T
A
= 25°C
WDFN-14TL 3x2 ------------------------------------------------------------------------------------------------------------ 3.11W
Package Thermal Resistance (Note 2)
WDFN-14TL 3x2,
θ
JA
------------------------------------------------------------------------------------------------------- 32.1°C/W
WDFN-14TL 3x2,
θ
JC
------------------------------------------------------------------------------------------------------ 6.3°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
CDM (Charged-Device Model) ------------------------------------------------------------------------------------------- 1kV
Recommended Operating Conditions
(Note 4)
0.8V to V
DD
2.5V to 5.5V
0V to V
DD
−40°C
to 125°C
−40°C
to 85°C
V
IN1,2
, Input Voltage Range ----------------------------------------------------------------------------------------------
V
DD
, Charge Pump Input Voltage Range ------------------------------------------------------------------------------
V
EN1,2
, EN Voltage Range ------------------------------------------------------------------------------------------------
Junction Temperature Range ---------------------------------------------------------------------------------------------
Ambient Temperature Range ---------------------------------------------------------------------------------------------
Electrical Characteristics
(V
IN
= 0.8V to 5.5V, T
A
= 25°C, unless otherwise specified)
Parameter
EN Input Supply
Input Voltage
High-Level
Low-Level
Symbol
V
ENH
V
ENL
Test Conditions
Min
1.4
0
Typ
--
--
--
Max
5.5
0.5
1
Unit
V
A
ENx Pin Input Leakage Current I
EN
V
EN
= 5.5V
--
(V
DD
= 5V, V
IN
= 0.8V to V
DD
, T
A
= 25°C, unless otherwise specified)
Parameter
Power Supplies and Currents
V
DD
Quiescent Current
(Both Channels)
V
DD
Quiescent Current
(Single Channel)
V
DD
Shutdown Current
Symbol
Test Conditions
I
OUT1
= I
OUT2
= 0A
V
IN1,2
= V
EN1,2
= V
DD
= 5V
I
OUT1
= I
OUT2
= 0A
V
IN1,2
= V
EN1
= V
DD
= 5V,
V
EN2
= GND
V
EN1,2
= GND, V
OUT1,2
= 0V
Min
Typ
Max
Unit
I
IN(VDD, ON)
--
75
115
A
I
IN(VDD, ON)
I
IN(VDD, OFF)
--
--
55
--
--
2
A
A
Copyright
©
2014 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
4
DS9745A-00 August 2014
RT9745A
Parameter
Symbol
Test Conditions
V
IN1,2
= 5V
V
IN1,2
Off-State Supply Current
I
IN(VIN, OFF)
(Per Channel)
Resistance Characteristics
V
IN
= 5V
V
IN
= 3.3V
ON-State Resistance
R
ON
I
OUT
=
200mA,
V
DD
= 5V
V
IN
= 1.8V
V
IN
= 1.5V
V
IN
= 1.2V
V
IN
= 0.8V
Output Pull-down Resistance
R
PD
V
EN
= 0V, V
IN
= 5V, I
OUT
= 15mA
--
--
--
--
--
--
--
27
27
27
27
27
27
220
30
30
30
30
30
30
300
m
V
EN1,2
= GND,
V
OUT1,2
= 0V
V
IN1,2
= 3.3V
V
IN1,2
= 1.8V
V
IN1,2
= 0.8V
Min
--
--
--
--
Typ
--
--
--
--
Max
8
3
2
1
A
Unit
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 high effective thermal conductivity four-layer test board per JEDEC 51-7.
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
©
2014 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS9745A-00 August 2014
www.richtek.com
5
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