RICHTEK RT9703GS

RT9703
80mΩ
Ω, 3A Smart Universal Power Switch with Flag
General Description
The RT9703 is a low voltage, high performance single
N-MOSFET power switch, designed for power rail on/off
control with low RDS(ON) ≈ 80mΩ and full protection
functions. The RT9703 equipped with a charge pump
circuitry to drive the internal MOSFET switch and a flag
output is available to indicate fault conditions against large
di/dt which may cause the supply to fall out of regulation.
In order to fit different application, an IP pin is offered for
current limit point setting, a resistor from IP to ground
sets the current limit for the switch.
Features
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Additional features include soft-start to limit inrush current
during plug-in, thermal shutdown to prevent catastrophic
switch failure from high-current loads, under-voltage
lockout (UVLO) to ensure that the device remains off
unless there is a valid input voltage present, a precision
resistor-programmable output current limit up to 3.5A.
Besides, the lower quiescent current as 30μA making this
device ideal for portable battery-operated equipment.
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The RT9703 is available in SOP-8 package requiring
minimum board space and smallest components.
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RT9703
Package Type
S : SOP-8
Operating Temperature Range
P : Pb Free with Commercial Standard
G : Green (Halogen Free with Commercial Standard)
Reverse Current Flow Blocking (no body diode) i.e.
Output Can Be Forced Higher than Input (Off-State)
Low Supply Current :
`30μ
μA Typical at Switch on State
`Less than 1μ
μA Typical at Switch Off State
Guaranteed 3A Continuous Load Current
Wide Input Voltage Ranges : 2V to 5.5V
Open-Drain Fault Flag Output
Hot Plug-In Application (Soft-Start)
1.7V Typical Under-Voltage Lockout (UVLO)
Thermal Shutdown Protection
Smallest SOP-8 Package Minimizes Board Space
RoHS Compliant and 100% Lead (Pb)-Free
Applications
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Ordering Information
Adjustable Current Limiting up to 3.5A
Built-In (Typically 80mΩ
Ω) N-MOSFET
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LCD Monitor, LCD-TV
USB Power Module for ADSL
Information Appliance and Set-Top Box
Battery-Powered Equipment
Hot-Plug Power Supplies
ACPI Power Distribution
PCI Bus Power Switching
Motherboard & Notebook PCs
PC Card Hot Swap Application
Pin Configurations
(TOP VIEW)
Note :
RichTek Pb-free and Green products are :
`RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.
`Suitable for use in SnPb or Pb-free soldering processes.
`100%matte tin (Sn) plating.
DS9703-08 March 2007
FLG
8
IP
VOUT
2
7
VIN
VOUT
3
6
VIN
GND
4
5
EN
SOP-8
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RT9703
Typical Application Circuit
Pull-Up Resistor (10K to 100K)
Supply Voltage
VIN
IP
10uF
Fault Flag
RSET
RT9703
EN
VOUT
GND
+
Chip Enable
FLG
Peripheral
33uF
Functional Pin Description
Pin Name
Pin Function
VIN
Power Input Voltage
VOUT
Output Voltage
GND
Ground
EN
Chip Enable (Active High)
FLG
Open-Drain Fault Flag Output
IP
Current Limit Programming Input
Function Block Diagram
EN
Bias
+
Oscillator
Charge
Pump
Thermal
Protection
IP
-
UVLO
-
+
VIN
VREF
Gate
Control
Output Voltage
Detection
VOUT
FLG
Delay
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DS9703-08 March 2007
RT9703
Test Circuits
1
2
RFG
ISUPPLY
VIN
VIN
+
A
CIN
FLG
S1
RT9703
GND
A
IP
VIN
A
FLG
VOUT
Chip Enable
RL
COUT
RSET
ILEAKAGE
RT9703
VOUT
+
EN
CIN
VIN
IOUT
VOUT
Chip Enable
VFLG
+
ISUPPLY
EN
IL
3
A
RL
GND IP
RSET
4
RFG
VRDS(ON)
V
IOUT
VIN
+
CIN
VIN
COUT
RT9703
RT9703
FLG
EN
GND
VFLG
FLG
VOUT
+
CIN
+
+
VIN
VOUT
VIN
COUT
RL
VOUT
IL
EN
IP
GND IP
VCE
RSET
RSET
5
S2
+
VIN
FLG
RT9703
IOUT
VOUT
+
VIN
CIN
COUT
EN
VOUT
A
S3
RL
IL
GND IP
RSET
Note: Above test circuits reflected the graphs shown on “ Typical Operating Characteristics” are as follows:
1–Turn-On Rising & Turn-Off Falling Time vs. Temperature, Turn-On & Off Response, Flag Response at Chip Enable, Flag
Response (Enable into Current Limit)
2–On-State & Off-State Supply Current vs. Input Voltage/Temperature, Turn-Off Leakage Current vs. Temperature
3–On-Resistance vs. Input Voltage/Temperature
4–EN Threshold Voltage vs. Input Voltage/Temperature, Flag Delay Time vs. Input Voltage/Temperature, UVLO Threshold
vs. Temperature, UVLO at Rising & Falling
5–Current Limit vs. Input Voltage/Temperature/RSET, Current Limit Factor vs. RSET, Short Circuit Current vs. Input Voltage,
Inrush Current Response, Soft-Start Response, Current-Limit & Short Circuit with Thermal Shutdown, Short-Circuit
Response
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RT9703
Absolute Maximum Ratings
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(Note 1)
Supply Voltage --------------------------------------------------------------------------------------------------------- 6.5V
Chip Enable Input Voltage ------------------------------------------------------------------------------------------- −0.3V to 6.5V
Flag Voltage ------------------------------------------------------------------------------------------------------------ 6.5V
Power Dissipation, PD @ TA = 25°C
SOP-8 -------------------------------------------------------------------------------------------------------------------- 0.95W
Package Thermal Resistance
SOP-8, θJA -------------------------------------------------------------------------------------------------------------- 104°C/W
Junction Temperature ------------------------------------------------------------------------------------------------- 125°C
Lead Temperature (Soldering, 10 sec.) --------------------------------------------------------------------------- 260°C
Storage Temperature Range ---------------------------------------------------------------------------------------- −65°C to 150°°C
ESD Susceptibility (Note 2)
HBM (Human Body Mode) ------------------------------------------------------------------------------------------ 8kV
MM (Machine Mode) -------------------------------------------------------------------------------------------------- 800V
Recommended Operating Conditions
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(Note 3)
Supply Input Voltage -------------------------------------------------------------------------------------------------- 2V to 5.5V
Chip Enable Input Voltage ------------------------------------------------------------------------------------------- 0V to 5.5V
Junction Temperature Range ---------------------------------------------------------------------------------------- −20°C to 100°C
Electrical Characteristics
(VIN = 5V, CIN = COUT = 1μF, TA = 25°C, unless otherwise specified)
Parameter
Switch On Resistance
Symbol
Test Conditions
Min
Typ
Max
Units
mΩ
RDS(ON)
IOUT = 3A (Note 8)
--
80
100
ISW_ON
Switch On, VOUT = Open
--
30
50
ISW_OFF
Switch Off, VOUT = Open
--
0.1
1
CE Threshold Logic-Low Voltage VIL
(Note 7)
Logic-High Voltage VIH
Switch Off
--
--
0.8
V
Switch On
2.0
--
--
V
CE Input Current
ICE
VCE = 0V to 5.5V
--
0
--
μA
Output Leakage Current
ILEAKAGE
VCE = 0V, RLOAD = 0Ω
--
0.5
10
μA
Output Turn-On Rise Time
TON_RISE
10% to 90% of VOUT rising
--
1.5
--
ms
Current Limit Factor (Note 5)
ILIM x RSET
--
210k
--
A‚Ω
Max. Current Limit Setting (Note 6) ILIMSET
VIN = 3.3V to 5.5V, RSET = 60kΩ
--
--
3.5
A
−20
--
+20
%
--
15
400
Ω
Supply Current
μA
Current Limit Setting Accuracy
ΔILIMSET
ILIMSET = 0.5A to 3A
(RSET = 420kΩ to 70kΩ)
FLAG Output Resistance
RFLG
ISINK = 1mA
FLAG Off Current
IFLG_OFF VFLG = 5V
--
0.01
1
μA
FLAG Delay Time (Note 4)
tD
2
4.6
8
ms
Under-Voltage Lockout
VUVLO
VIN increasing
1.3
1.7
--
V
Under-Voltage Hysteresis
ΔVUVLO
VIN decreasing
--
0.1
--
V
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Form fault condition to FLG assertion
DS9703-08 March 2007
RT9703
Parameter
Symbol
Test Conditions
Min
Typ
Max
Units
Thermal Shutdown Protection
TSD
--
130
--
°C
Thermal Shutdown Hysteresis
ΔTSD
--
10
--
°C
Note 1. Stresses listed as the above "Absolute Maximum Ratings" may cause permanent damage to the device. These are for
stress ratings. 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 for extended
periods may remain possibility to affect device reliability.
Note 2. Devices are ESD sensitive. Handling precaution recommended.
Note 3. The device is not guaranteed to function outside its operating conditions.
Note 4. The FLAG delay time is input voltage dependent, see “ Typical Operating Characteristics” graph for further details.
Note 5. Current limit is determined by: ILIMIT = 210k/RSET, where RSET is in ohms.
Note 6. It is important to note that the maximum current limit value shall be set properly in accordance with its supply voltage
otherwise which it may result in the failure occurrence. See “ Maximum Current Limit vs. Supply Voltage” graph shown
on the applications information section for further details.
Note 7. For input voltage lower than 5V, the threshold level will subject to ±0.6V deviation throughout the operating junction
temperature range. Refer to the “ Typical Operating Characteristics” graph for further details.
Note 8. RDS(ON) is measured at constant junction temperature by using a 1ms current pulse.
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RT9703
Typical Operating Characteristics
2
On-State Supply Current vs. Input Voltage
50
VEN = 5V
1.5
Supply Current (uA) A
CIN = 10uF
RL = Open
40
Off-State Supply Current vs. Input Voltage
2
VEN = 5V
45
Supply Current (uA) A
2
RSET = 100kΩ
35
30
25
20
CIN = 10uF
COUT = 33uF
1
RL = Open
0.5
RSET = 100kΩ
0
-0.5
-1
-1.5
15
-2
10
1.5
2
2.5
3
3.5
4
4.5
5
1.5
5.5
2
2.5
On-State Supply Current vs. Temperature
50
COUT = 33uF
RL = Open
35
RSET = 100kΩ
30
25
20
15
5
5.5
CIN = 10uF
COUT = 33uF
1
RL = Open
0.5
RSET = 100kΩ
0
-0.5
-1
-1.5
10
-2
-40
-20
0
20
40
60
80
100
120
-40
Temperature (° C)
5
-20
0
20
5
60
80
100
120
Current Limit vs. Temperature
2.1
CIN = 10uF, COUT = 33uF
VIN = 5V
CIN = 10uF, COUT = 33uF
RL = 0.5Ω , RSET = 116kΩ
S2 = ON, S3 = OFF
RL = 0.5Ω, RSET = 116kΩ
2
40
Temperature (° C)
Current Limit vs. Input Voltage
2.1
2
S2 = ON, S3 = OFF
Current Limit (A)
Current Limit (A)
4.5
VIN = 5V, VEN = 0V
1.5
CIN = 10uF
40
4
Off-State Supply Current vs. Temperature
2
Supply Current (uA) A
Supply Current (uA) A
2
VIN = VEN = 5V
45
3.5
Input Voltage (V)
Input Voltage (V)
2
3
1.9
1.8
1.7
1.9
1.8
1.7
1.6
1.6
2
2.5
3
3.5
4
Input Voltage (V)
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4.5
5
5.5
-40
-20
0
20
40
60
80
100
120
Temperature (° C)
DS9703-08 March 2007
RT9703
3
5
Current Limit vs. RSET
4
VIN = 5V, RL = 0.5Ω
3.5
On-Resistance (mΩ)
S2 = ON, S3 = OFF
2.5
2
1.5
1
IOUT = 0.5A, RSET = 50kΩ
69
CIN = 10uF, COUT = 33uF
3
Current Limit (A)
On-Resistance vs. Input Voltage
70
0.5
CIN = 10uF, COUT = 33uF
68
67
66
65
64
63
0
62
50
100
150
200
250
300
350
400
450
500
2
2.5
3
RSET (k Ω)
3
On-Resistance vs. Temperature
88
5
4
4.5
5
5.5
Short Circuit Current Response
VIN = 5V, CIN = 10uF, COUT = 0.1uF
RSET = 175kΩ, S2 = S3 = ON
IOUT = 0.5A, RSET = 50kΩ
CIN = 10uF, COUT = 33uF
On-Resistance (mΩ)
3.5
Input Voltage (V)
VIN = 5V
78
VOUT (5V/Div)
68
58
IOUT (0.5A/Div)
48
-40
-20
0
20
40
60
80
100
Time (10ms/Div)
120
Temperature (° C)
Inrush Current Response
COUT = 1000uF
COUT = 470uF
COUT = 1uF
(1A/Div)
VIN = 5V, CIN = 10uF
RL = 0.5Ω,
RSET = 175kΩ,
S2 = ON, S3 = OFF
Time (5ms/Div)
EN
Pin Threshold
vs.Voltage
Input
CE
Threshold
VoltageVoltage
vs. Input
4
2.4
EN Pin Threshold Voltage (V)
CE Threshold Voltage (V)
EN
5
CIN = 10uF, COUT = 33uF
IL = 100mA, RSET = 100kΩ
2
1.6
1.2
0.8
0.4
0
2
2.5
3
3.5
4
4.5
5
5.5
Input Voltage (V)
DS9703-08 March 2007
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RT9703
CE Threshold
Voltage vs.
Temperature
EN Pin Threshold
Voltage
vs.
4
Turn-On Rising Time vs. Temperature
1
4
VIN = 5V, IL = 100mV
CIN = 10uF, COUT = 33uF
2
Turn-On Rising Time (ms)
ENCE
PinThresold
Threshold
Voltage
Voltage
(V)(V)
2.4
RSET = 100kΩ
1.6
1.2
0.8
0.4
VIN = VEN = 5V
3.5
CIN = 10uF, COUT = 1uF
RL = 30Ω, RSET = 200kΩ
3
S1 = ON
2.5
2
1.5
1
0.5
0
0
-40
-20
0
20
40
60
80
100
120
-40
-20
0
Turn-Off Falling Time vs. Temperature
6
CIN = 10uF, COUT = 1uF
RL = 30Ω, RSET = 200kΩ
S1 = ON
4
3
2
1
60
80
100
120
0.2
VIN = 5V, VEN = 0V
CIN = 10uF, COUT = 33uF
RL = 0Ω, RSET = 100kΩ
0.1
0
-0.1
-0.2
-0.3
0
-40
-20
0
20
40
60
80
100
-40
120
-20
0
4
4
Flag Dealy Time vs. Input Voltage
10
40
60
80
100
120
Flag Delay Time vs. Temperature
9
VEN = 5V
CIN = 10uF, COUT = 33uF
8
20
Temperature (° C)
Temperature (° C)
VIN = VEN = 5V
CIN = 10uF, COUT = 33uF
RL = 0.5Ω, RSET = 100kΩ
Flag Delay Time (ms)
Flag Delay Time (ms)
40
Turn-Off Leakage Current vs. Temperature
0.3
VIN = 5V, VEN = 0V
5
2
Turn-Off Leakage Current (uA) a
Turn-Off Falling Time (us)
1
20
Temperature (° C)
Temperature (° C)
RFG = 1kΩ
6
4
2
0
8
RL = 0.5Ω, RSET = 100kΩ
RFG = 1kΩ
7
6
5
4
2
2.5
3
3.5
4
Input Voltage (V)
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4.5
5
5.5
-40
-20
0
20
40
60
80
100
120
Temperature (° C)
DS9703-08 March 2007
RT9703
4
UVLO Threshold vs. Temperature
3.5
UVLO Threshold (V)
3
1
Turn-On Response
CIN = 10uF, COUT = 33uF
RL = 1kΩ, RSET = 100kΩ
2.5
VEN (5V/
2
1.5
1
0.5
VOUT (1V/
0
-40
-20
0
20
40
60
80
100
VIN = 5V, S1 = ON
CIN = 10uF, COUT = 1uF
RL = 33Ω, RSET = 200kΩ
Time (250us/Div)
120
Temperature (° C)
1
Turn-Off Response
4
UVLO at Rising
VIN = 5V, S1 = OFF
CIN = 10uF, COUT = 1uF
RL = 30Ω, RSET = 200kΩ
VEN (5V/Div)
VOUT (5V/Div)
VIN (1V/Div)
VOUT (1V/Div)
IL (100mA/Div)
Time (1ms/Div)
Time (100us/Div)
4
VIN = VEN = 5V
CIN = 1000uF, COUT = 1uF
1
UVLO at Falling
FLAG Response
when Enable into Current Limit
VIN = VEN = 5V
CIN = 1000uF, COUT = 1uF
RL = 30Ω, RSET = 200kΩ
VEN (5V/Div)
VFLG (5V/Div)
VIN (1V/Div)
VOUT (1V/Div)
Time (25ms/Div)
DS9703-08 March 2007
IL (1A/Div)
VIN = 5V
CIN = 1uF, COUT = 33uF
RL = 0.5Ω, RSET = 175kΩ
RFG = 1kΩ, S1 = OFF
Time (1ms/Div)
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RT9703
1
FLAG Response at Chip Enable
5
Current Limit with Thermal Shutdown
VIN = 5V
CIN = 10uF
COUT = 33uF
RL = 0.5Ω, RSET = 116kΩ
S2 = ON, S3 = OFF
VEN (5V/Div)
VFLG (5V/Div)
IL (0.5A/Div)
VEN (5V/Div)
VIN = 5V
CIN = 1uF, COUT = 33uF
RL = 0.5Ω, RSET = 420kΩ
IL (1A/Div)
RFG = 1kΩ, S1 = OFF
Time (50ms/Div)
Time (10ms/Div)
5
Short- Circuit with Thermal Shutdown
5
Soft-Start Response with Current Limit
VIN = 5V, CIN = 10uF, COUT = 33uF
RSET = 140kΩ, S2 = ON, S3 = ON
VIN (5V/Div)
VTRIGGER (5V/Div)
VEN (5V/Div)
VOUT (5V/Div)
IL (2A/Div)
IL (0.5A/Div)
Time (10ms/Div)
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CIN = 10uF, COUT = 1uF
RL = 0.5Ω, RSET = 70kΩ
Time (1ms/Div)
DS9703-08 March 2007
RT9703
Applications Information
The RT9703 is a high-side, N-Channel, power switch
≈
available with active-high enable input. Low RDS(ON)dd
80mΩ and full protection functions make it optimized to
replace complex discrete on/off control circuitry.
Input and Output
VIN (input) is the power source connection to the internal
circuitry and the drain of the MOSFET. VOUT (output) is
the source of the MOSFET. In a typical application, current
flows through the switch from VIN to VOUT toward the load.
If VOUT is greater than VIN, current will flow from VOUT to
VIN since the MOSFET is bidirectional when on.
Unlike a normal MOSFET, there is no a parasitic body
diode between drain and source of the MOSFET, the
RT9703 prevents reverse current flow if VOUT being
externally forced to a higher voltage than VIN when the
output disabled (VEN < 0.8V).
D
S
S
D
Fault Flag
The RT9703 provides a FLG signal pin which is an
N-Channel open drain MOSFET output. This open drain
output goes low when VOUT < VIN −1V, current limit or the
die temperature exceeds 130°C approximately. The FLG
output is capable of sinking a 10mA load to typically
150mV above ground. The FLG 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 the case of an over-current condition, FLG
will be asserted only after the flag response delay time,
tD, has elapsed. This ensures that FLG is asserted only
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 a highly large capacitive load
is connected and causes a high transient inrush current
that exceeds the current limit threshold. The FLG
response delay time tD is typically 4.6ms.
Under-voltage Lockout
G
Normal MOSFET
G
RT9703
Chip Enable Input
The switch will be disabled when the EN pin is in a logic
low condition. During this condition, the internal circuitry
and MOSFET are turned off, reducing the supply current
to 0.1μA typically. The maximum guaranteed voltage for a
logic low at the EN pin is 0.8V. A minimum guaranteed
voltage of 2V at the EN pin will turn the RT9703 back on.
Floating the input may cause unpredictable operation. EN
should not be allowed to go negative with respect to GND.
The EN pin may be directly tied to VIN to keep the part on.
Under-voltage lockout (UVLO) prevents the MOSFET switch
from turning on until input voltage exceeds approximately
1.7V. If input voltage drops below approximately 1.3V, UVLO
turns off the MOSFET switch, FLG will be asserted
accordingly. Under- voltage detection functions only when
the chip enable input is enabled.
Current Limiting and Short-Circuit Protection
The current limit circuitry prevents damage to the MOSFET
switch and external load. It is user adjust- able with an
external set resistor, RSET, ILIMIT = 210kΩ/RSET in the range
of 0.5A to 3A. The accuracy of current limit set point may
vary with operating temperature and supply voltage. See
“Typical Operating Characteristics” graph for further details.
Soft-Start for Hot Plug-In Applications
In order to eliminate the upstream voltage droop caused
by the large inrush current during hot-plug events, the
“soft-start” feature effectively isolates the power source
from extremely large capacitive loads.
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RT9703
The normal current limit value, ILIMIT, is set with an external
resistor between IP (pin 8) and GND (pin 4). When a heavy
load or short circuit is applied to an enabled switch, a
large transient current may flow until the current limit
circuitry responds. Once this current limit threshold is
exceeded, the device enters constant current mode until
the thermal shutdown occurred or the fault is removed. It
is important to note that the maximum current limit value
shall be set properly in accordance with its supply voltage
otherwise it may result in the failure occurrence. The graph
below shows the maximum current limit and supply
voltage on the safe operation area.
Maximun Current Limit vs. Supply Voltage
Maximun Current Limit (A) A
5
TA = 25°C
the junction temperature does not exceed 100°C. With
all possible conditions, the junction temperature must be
within the range specified under operating conditions.
Power dissipation can be calculated based on the output
current and the RDS(ON) of switch as below.
PD = RDS(ON) x IOUT2
Although the devices are rated for 3A of output current,
but the application may limit the amount of output current
based on the total power dissipation and the ambient
temperature. The final operating junction temperature for
any set of conditions can be estimated by the following
thermal equation :
PD(MAX) = ( TJ(MAX) - TA ) / θJA
Where TJ(MAX) is the maximum junction temperature of the
die (100°C) and TA is the maximum ambient temperature.
The junction to ambient thermal resistance (θJA) for SOP8 package at recommended minimum footprint is 104°C/
W (θJA is layout dependent).
4.5
4
3.5
3
2.5
2
Supply Filter/Bypass Capacitor
1.5
1
0.5
0
2
2.5
3
3.5
4
4.5
5
5.5
Supply Voltage (V)
Thermal Shutdown
Thermal shutdown is employed to protect the device from
damage if the die temperature exceeds approximately
130°C. If enabled, the switch automatically restarts when
the die temperature falls 10°C. The output and FLG signal
will continue to cycle on and off until the device is disabled
or the fault is removed.
Power Dissipation
The device's junction temperature depends on several
factors such as the load, PCB layout, ambient temperature
and package type. The output pin of RT9703 can deliver
a current of up to 3A over the full operating junction
temperature range. However, the maximum output current
must be derated at higher ambient temperature to ensure
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12
A 10μF low-ESR ceramic capacitor from VIN to GND (the
amount of the capacitance may be increased without limit),
located at the device is strongly recommended to prevent
the input voltage drooping during hot-plug events.
However, higher capacitor values will further reduce the
voltage droop on the input. Furthermore, without the
bypass capacitor, an output short may cause sufficient
ringing on the input (from source lead inductance) to
destroy the internal control circuitry. An important note to
be award of is the parasitic inductance of PCB traces can
cause over-voltage transients if the PCB trace has even
a few tens of nH of inductance. It is recommended to use
aluminum electrolytic acted the supply capacitor to prevent
the device from being damaged. The input transient MUST
not exceed 6.5V of the absolute maximum supply voltage
even for a short duration.
DS9703-08 March 2007
RT9703
Fault Flag Filtering (Optional)
The transient inrush current to downstream capacitance
may cause a short-duration error flag, which may cause
erroneous over-current reporting. A simple 1ms RC lowpass filter (10kΩ and 0.1μF) in the flag line eliminates
short-duration transients.
GND
VIN
IP
EN
PCB Layout
In order to meet the voltage drop, droop, and EMI
requirements, careful PCB layout is necessary. The
following guidelines must be considered:
z
z
z
z
Keep all input and output traces as short as possible
and use at least 150-mil & 2 ounce copper for all races.
GND
FLG
VOUT
Avoid vias as much as possible. If vias are necessary,
make them as large as feasible.
Place a ground plane under all circuitry to lower both
resistance and inductance and improve DC and transient
performance (Use a separate ground and power plans
if possible).
GND
Board Layout
Locate the bypass capacitors as close as possible to
the input and output pin of the RT9703.
DS9703-08 March 2007
www.richtek.com
13
RT9703
Outline Dimension
H
A
M
J
B
F
C
I
D
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
Min
Max
A
4.801
5.004
0.189
0.197
B
3.810
3.988
0.150
0.157
C
1.346
1.753
0.053
0.069
D
0.330
0.508
0.013
0.020
F
1.194
1.346
0.047
0.053
H
0.170
0.254
0.007
0.010
I
0.050
0.254
0.002
0.010
J
5.791
6.200
0.228
0.244
M
0.400
1.270
0.016
0.050
8-Lead SOP Plastic Package
Richtek Technology Corporation
Richtek Technology Corporation
Headquarter
Taipei Office (Marketing)
5F, No. 20, Taiyuen Street, Chupei City
8F, No. 137, Lane 235, Paochiao Road, Hsintien City
Hsinchu, Taiwan, R.O.C.
Taipei County, Taiwan, R.O.C.
Tel: (8863)5526789 Fax: (8863)5526611
Tel: (8862)89191466 Fax: (8862)89191465
Email: [email protected]
www.richtek.com
14
DS9703-08 March 2007