RICHTEK RT9701CBL

RT9701
100mΩ
Ω Power Distribution Switches
General Description
Features
The RT9701 is an integrated 100mΩ power switch
z
for self-powered and bus-powered Universal Series
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100mΩ
Ω Typ. High-Side NMOSFET (SOT- 25)
Guaranteed 1.1A Continuous Current
Bus (USB) applications. A built-in charge pump is
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1.5A Current Limit
used to drive the N-channel NMOSFET that is free
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Small SOT- 25 Package Minimizes Board Space
of parasitic body diode to eliminate any reversed
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Soft Start
current flow across the switch when it is powered
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Thermal Protection
off. Its low quiescent supply current (23µA) and
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Low 23µ
µA Supply Current
small package (SOT-25) is particularly suitable in
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Wide Input Voltage Range: 2.2V ~ 6V
battery-powered portable equipment.
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UL Approved - #E219878
Several protection functions include soft start to limit
Pin Configurations
inrush current during plug-in, current limiting at 1.5A
to meet USB power requirement, and thermal
Part Number
Pin Configurations
TOP VIEW
shutdown to protect damage under over current
RT9701CBL
conditions.
(Plastic SOT-25)
5
Applications
4
1
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Battery-Powered Equipment
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Motherboard USB Power Switch
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USB Device Power Switch
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Hot-Plug Power Supplies
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Battery-Charger Circuits
2
3
VOUT
GND
VIN
VIN
VOUT
TOP VIEW
RT9701CB
5
(Plastic SOT-25)
1
4
2
3
Ordering Information
RT9701… ……
1.
2.
3.
4.
5.
1.
2.
3.
4.
5.
VOUT
GND
VIN
CE
VOUT
Typical Application Circuit
Package type
BL : SOT-25
B : SOT-25
RT9701 CBL
Operating temperature range
C: Commercial standard
VIN
VIN
CIN
1 µF
VOUT
VOUT
VIN
GND
VOUT
*COUT
470 µF
Marking Information
Part Number
Marking
RT9701CBL
AH
RT9701CB
C0
DS9701-05 October 2001
* 470µF, Low ESR Electrolytic
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RT9701
Pin Description
Pin Name
Pin Function
VIN
Power Input
VOUT
Output Voltage
GND
Ground
CE
Chip Enable
Test Circuits
VOUT
VIN
RT9701 CBL
VIN
VOUT
CIN
VIN
+
GND
IOUT
VOUT
+
CL
IL
RL
Test Circuit 1
VIN
VOUT
VIN-SW
RT9701 CBL
VIN
VOUT
Switch Off
VIN
+
CIN
VOUT
GND
+
CL
RL
Test Circuit 2
VOUT
VIN
RT9701 CB
VIN
CIN
+ VCE
IOUT
VOUT
CE
GND
VOUT
On
CL
+
RL
IL
Off
Test Circuit 3
Test Circuit 2 is performed by charging an external tank of bulk capacitor to the input then applying this voltage to
the input of the unit.
All typical operating characteristics curves showed are referred to Test Circuit 1, unless specified to Test Circuit 2
or Test Circuit 3.
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DS9701-05 October 2001
RT9701
Function Block Diagram
VIN
CE
Current
Bias
Charge
Pump
Oscillator
Limit
RS
Control
Thermal
Detection
(VIN)
(VOUT)
NMOSFET
VOUT
GND
Absolute Maximum Ratings
z
Supply Voltage
7V
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Chip Enable
-0.3V ~ 7V
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Power Dissipation, PD @ TA = 25°C
SOT-25
0.25W
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Operating Junction Temperature Range
-20°C ~ 100°C
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Storage Temperature Range
-65°C ~ 150°C
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Package Thermal Resistance
SOT-25, θJA
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250°C /W
VOUT ESD Level
HBM (Human Body Mode)
8KV
MM (Machine Mode)
800V
DS9701-05 October 2001
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3
RT9701
Electrical Characteristics
(VIN = 5V, CIN = COUT = 1µF, TA = 25°C, unless otherwise specified)
Parameter
Symbol
Input Voltage Range
Output NMOFET RDS(ON)
Test Conditions
Min
Typ
Max
Units
2.2
--
6
V
IL = 1A
--
100
130
IL = 1A
--
105
135
VIN = 3V
--
19
40
VIN = 5V
--
23
45
--
400
--
µS
1.1
1.5
2
A
--
1.0
--
A
VIN
RT9701CBL
RT9701CB
RDS(ON)
Supply Current
Output Turn-On Rising Time
TR
RL = 10Ω, 90% Settling
Current Limit Threshold
ILIMIT
RL = 2Ω
Short-circuit Fold Back Current
IOS
VOUT = 0V, measured
prior to thermal shutdown
mΩ
µA
CE Input High Threshold
RT9701CB
2.0
--
--
V
CE Input Low Threshold
RT9701CB
--
--
0.8
V
Shutdown Supply Current
RT9701CB
IOFF
CE = “0”
--
0.1
1
µA
Output Leakage Current
RT9701CB
ILEAKAGE CE = “0”, VOUT = 0V
--
0.5
10
µA
1.3
1.8
--
V
--
100
--
mV
VIN Under Voltage Lockout
UVLO
VIN Under Voltage Hysteresis
Thermal Limit
TSD
--
130
--
°C
Thermal Limit Hysteresis
∆TSD
--
20
--
°C
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DS9701-05 October 2001
RT9701
Typical Operating Charateristics
Supply Current vs. Temp.
40
VIN = 5V
35
TA = 25° C
Ta
35
µ A)
Quiescent Current (µ
µ A)
Quiessent Current ( µ
Supply Current vs. Voltage
40
30
25
20
15
10
5
30
25
20
15
10
5
0
0
-40
-20
0
20
40
60
80
100
2.0
120
2.5
3.0
Temperature (ºC)
On-Resistance vs. Temp.
VIN = 5V
120
RT9701CB
RT9701CBL
100
5.0
5.5
6.0
Ta
25°C
T
A ==25°C
RT9701CBL
RT9701CBL
140
On-Resistance (mOhm)
Ω)
On-Resistance (m Ω))
4.5
160
80
60
40
20
120
100
80
60
40
20
0
0
-40
-20
0
20
40
60
80
100
120
2.0
2.5
3.0
Temperature (°C)C)
3.5
4.0
4.5
5.0
5.5
6.0
(V) (V)
VVoltage
IN Voltage
Current Limit vs. Temp.
Current Limit vs. Voltage
2.20
1.80
VIN = 5V
2.00
1.80
1.60
1.40
1.20
1.35
1.13
0.90
0.68
1.00
0.45
0.80
0.23
0.60
TA = 25°C
1.58
Current Limit (A)
Current Limit (A)
4.0
On-Resistance vs. Voltage
160
140
3.5
VINVoltage
Voltage(V)
(V)
0.00
-40
-20
0
20
40
60
Temperature ( °C) C)
DS9701-05 October 2001
80
100
120
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
(V)
VVoltage
IN Voltage (V)
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RT9701
Short Circuit Current vs. Temp.
Short Circuit Current vs. Voltage
1950
1400
VIN = 5V
Short Circuit Current (mA)
Short Circuit Current (mA)
1300
1200
1100
1000
900
800
700
Ta
T
A = 25° C
1700
1450
1200
950
700
450
600
500
200
-40
-20
0
20
40
60
80
100
120
2.0
2.5
3.0
° C)
Temperature ( °C)
3.5
4.0
4.5
5.0
5.5
6.0
(V)
VVoltage
IN Voltage (V)
CE Threshold vs. Temp.
CE Threshold vs. Voltage
2.4
2.4
VIN = 5V
2.0
1.6
Rising
1.2
Falling
0.8
CE Threshold (V)
CE Threshold (V)
2.0
1.6
Rising
1.2
Falling
0.8
0.4
0.4
0.0
0.0
-40
-20
0
20
40
60
Temperature (ºC)
TA = 25 °C
2.0
80
100 120
*Test Circuit 3
Turn On Rising Time vs. Temp.
360
270
180
RL = 30Ω
90
CL = 1µ F Ceramic
0
-40
-20
0
20
40
60
Temperature (°C)
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6
80
100 120
*Test Circuit 3
4.0
4.5
5.0
5.5
6.0
*Test Circuit 3
Turn Off Falling Time vs. Temp.
VIN = 5V
Turn-Off Falling Time (µµS)
Turn-On Rising Time ( µS)
µ S)
450
3.5
140
VIN = 5V
540
3.0
(V)
VVoltage
IN Voltage (V)
720
630
2.5
120
100
80
60
40
RL = 30Ω
20
CL = 1µF Ceramic
0
-40
-20
0
20
40
60
Temperature (° C)
80
100
120
*Test Circuit 3
DS9701-05 October 2001
RT9701
Shutdown Supply Current vs. Temp.
Turn-Off Leakage Current vs. Temp.
3.5
VIN = 5V
0.8
0.6
0.5
0.3
0.2
0.0
µ A)
Turn-Off Leakage Current (µ
µ A)
Turn-Off Supply Current (µ
0.9
VIN = 5V
3.0
2.5
2.0
1.5
1.0
0.5
0.0
-40
-20
0
20
40
60
Temperature (°C)
80
100 120
*Test Circuit 3
-40
-20
0
20
40
60
Temperature ( °C)
UVLO Threshold vs. Temp.
80
100 120
*Test Circuit 3
Inrush Current Response
3.50
VIN = 5V
UVLO Threshold (V)
3.00
2.50
CL = 100µF
2.00
CL = 33µF
1.50
1.00
324 >
T
TT
CL = 1µF
0.50
VLIN==1Ω,
5V,VRINL == 5V
1 ohm
R
ILOUT
=1A/Div
= 1A/Div
0.00
-40
-20
0
20
40
60
80
100
Time100µS/Div
(100µS/Div)
120
Temperature ( °C)
Turn-On Response
Turn-Off Response
RL = 30 Ω, CL = 1µF
CH1
CH1
1>
TT
T
1>
CH2
TT
2>
CH3
CH2
2>
T
TT
CH1: VCE : 5V/Div
CH2: VOUT : 1V/Div
3>
RL = 30 Ω, CL = 1µF
Time (100µS/Div)
DS9701-05 October 2001
*Test Circuit 3
CH1: VCE : 5V/Div
CH2: IOUT : 100mA/Div; CH3: VOUT : 2V/Div
Time (50µS/Div)
*Test Circuit 3
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RT9701
UVLO at Rising
UVLO at Falling
CH1
CH2
T
CH1
CH2
1>
2>
TT
T
CH1: VIN : 1V/Div
CH2: VOUT : 1V/Div
TT
1>
2>
RL = 30 Ω, CL = 1µF
CH1: VIN : 1V/Div
CH2: VOUT : 1V/Div
Time (500µS/Div)
RL = 30 Ω, CL = 1µF
Time (10mS/Div)
Inrush Short Circuit Response
*Test Circuit 2
Soft-start Short Circuit Response
T
VDROP =1.2V, depend on CIN ESR
IPEAK : depend on ESR & ESL
1>
CH1
CH22 >
CH1
T
1>
CH1
TT
CH1 : VIN : 2V/Div
CH2 : IL : 10A/Div
C IN = 1µF
C L = 1000µF
CH22 >
CH1 : VIN : 2V/Div
CH2 : IOUT : 1A/Div
CIN = 1µF
TT
25µS/Div
50µS/Div
Ramped Load Response
Current Limit Response
VOUT = 5V
4.9V
T
VOUT = 4.6V
CH1
1>
CH2
2>
Loading trigger
Current Limit Threshold
1.1A
TT
1>
CH2
2>
CH2: IOUT : 500mA/Div VIN = 5V, CL = 1µF
1mS/Div
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CH2: IOUT
ILOAD
: 1A/Div
: 1A/Div
VIN = 5V, CL = 0.1µF
RL = 1 Ω
ohm
5µS/Div
DS9701-05 October 2001
RT9701
Thermal Shut Down Response
T
CH1
1>
CH3
Thermal Shut Down
CH2
TT
2>
CH1: VCE : 5V/Div
Ω : 1A/Div
CH3: [email protected]
: 1A/Div
500mA/Div
CH2: [email protected] : 1A/Div
500mA/Div
VIN = 5V
Time50mS/Div
(50mS/Div)
Functional Description
The RT9701 is a high-side single N-channel switch
Current Limiting and Short Protection
with active-high enable input.
The current limit circuit is designed to protect the
system supply, the MOSFET switch and the load
Input and Output
from damage caused by excessive currents. The
VIN (input) is the power supply connection to the
current limit threshold is set internally to allow a
circuitry and the drain of the output MOSFET. VOUT
minimum of 1.1A through the MOSFET but limits the
(output) is the source of the output MOSFET. In a
output current to approximately 1.5A typical. When
typical circuit, current flows through the switch from
the output is short to ground, it will limit to a constant
VIN to VOUT toward the load. Both VOUT pins must
current 1A until thermal shutdown or short condition
be short on the board and connected to the load and
removed.
so do both VIN pins but connected to the power
source.
Thermal Shutdown
Thermal shutdown shuts off the output MOSFET if
the die temperature exceeds 130°C and 20°C of
hysteresis forces the switch turning off until the die
temperature drops to 110°C.
Soft Start
In order to eliminate the upstream voltage droop
caused by the large inrush current during hot-plug
events, the “soft-start” feature effectively isolates
power supplies from such highly capacitive loads.
Under-voltage Lockout
UVLO prevents the MOSFET switch from turning on
until input voltage exceeds 1.8V (typical). If input
voltage drops below 1.8V (typical), UVLO shuts off
the MOSFET switch.
DS9701-05 October 2001
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RT9701
Applications Information
Ferrite beads in series with all power and ground
lines are recommended to eliminate or significantly
RT9701CBL
VIN
VIN
VIN
CIN
1µ F
reduce EMI. In selecting a ferrite bead, the DC
VOUT2
VOUT
VOUT
VOUT1
GND
resistance of the wire used must be kept to a
minimum to reduce the voltage drop.
COUT
COUT
Reverse current preventing
The output MOSFET and driver circuitry are also
CIN = 1 µF, COUT = 470µF (Low ESR) on M/B
CIN = 1 µF, COUT = 330µF (Low ESR) on Notebook
CIN = 10µ F, C OUT = 1µ F on USB device
designed to allow the MOSFET source to be
externally forced to a higher voltage than the drain
(VOUT > VIN ≥ 0). To prevent reverse current from
Fig. 1 High Side Power Switch
such condition, disable the switch (RT9701CB) or
connect VIN to a fixed voltage under 1.3V.
RT9701CB
VIN
CIN
VIN
VOUT
CE
VOUT
VOUT2
Layout and Thermal Dissipation
z
VOUT1
possible. Keep all traces as short as possible to
GND
COUT
ON
Place the switch as close to the USB connector as
reduce
COUT
the
effect
of
undesirable
parasitic
inductance.
VCE
OFF
Fig. 2 High Side Power Switch with Chip Enable Control
z
Place the output capacitor and ferrite beads as
close to the USB connector as possible.
z
If ferrite beads are used, use wires with minimum
resistance and large solder pads to minimize
connection resistance.
Filtering
To limit the input voltage drop during hot-plug events,
z
If the package is with dual VOUT or VIN pins,
connect a 1µF ceramic capacitor from VIN to GND.
short both the same function pins as Fig.1 or Fig.2
However, higher capacitor values will further reduce
to reduce the internal turn-on resistance. If the
the voltage drop at the input.
output power will be delivered to two individual
ports, it is specially necessary to short both VOUT
Connect a sufficient capacitor from VOUT to GND.
pin at the switch output side in order to protect the
This capacitor helps to prevent inductive parasitics
switch when each port are plug-in separately.
from pulling VOUT negative during turn-off or EMI
damage to other components during the hotdetachment. It is also necessary for meeting the USB
specification during hot plug-in operation. If RT9701
is implanted in device end application, minimum 1µF
capacitor from VOUT to GND is recommended and
z
Under normal operating conditions, the package
can dissipate the channel heat away. Wide powerbus planes connected to VIN and VOUT and a
ground plane in contact with the device will help
dissipate additional heat.
higher capacitor values are also preferred.
In choosing these capacitors, special attention must
be paid to the Effective Series Resistance, ESR, of
the capacitors to minimize the IR drop across the
capacitor’s ESR. A lower ESR on this capacitor can
get a lower IR drop during the operation.
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DS9701-05 October 2001
RT9701
Package Information
D
C
B
b
H
A
e
Symbol
L
A1
Dimensions In Millimeters
Dimensions In Inches
Min
Max
Min
Max
A
0.889
1.295
0.035
0.051
A1
0.000
0.152
0.000
0.006
B
1.397
1.803
0.055
0.071
b
0.356
0.559
0.014
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
0.102
0.254
0.004
0.010
L
0.356
0.610
0.014
0.024
SOT- 25 Surface Mount Package
DS9701-05 October 2001
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RT9701
RICHTEK TECHNOLOGY CORP.
RICHTEK TECHNOLOGY CORP.
Headquarter
Taipei Office (Marketing)
6F, No. 35, Hsintai Road, Chupei City
8F-1, No. 137, Lane 235, Paochiao Road, Hsintien City
Hsinchu, Taiwan, R.O.C.
Taipei County, Taipei, R.O.C.
Tel: (8863)5510047 Fax: (8863)5537749
Tel: (8862)89191466 Fax: (8862)89191465
Email: [email protected]
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DS9701-05 October 2001