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RT9701
100m Power Distribution Switches
General Description
The RT9701 is an integrated 100m power switch for self-powered and bus-powered Universal Series Bus (USB) applications. A built-in charge pump is used to drive the N-channel NMOSFET that is free of parasitic body diode to eliminate any reversed current flow across the switch when it is powered off. Its low quiescent supply current (23A) and small package (SOT-25) is particularly suitable in battery-powered portable equipment. Several protection functions include soft start to limit inrush current during plug-in, current limiting at 1.5A to meet USB power requirement, and thermal shutdown to protect damage under over current conditions.
Features
100m Typ. High-Side NMOSFET (SOT- 25) Guaranteed 1.1A Continuous Current 1.5A Current Limit Small SOT- 25 Package Minimizes Board Space Soft Start Thermal Protection Low 23A Supply Current Wide Input Voltage Range: 2.2V ~ 6V UL Approved - #E219878
Pin Configurations
Part Number RT9701CBL (Plastic SOT-25)
5
Pin Configurations
TOP VIEW
4
Applications
Battery-Powered Equipment Motherboard USB Power Switch USB Device Power Switch Hot-Plug Power Supplies Battery-Charger Circuits RT9701CB (Plastic SOT-25)
1
2
3
1. 2. 3. 4. 5.
VOUT GND VIN VIN VOUT
TOP VIEW
5 4
1
2
3
Ordering Information
RT9701 Package type BL : SOT-25 B : SOT-25 Operating temperature range C: Commercial standard
1. 2. 3. 4. 5.
VOUT GND VIN CE VOUT
Typical Application Circuit
RT9701 CBL VIN CIN 1 F VIN VIN GND VOUT VOUT *COUT 470 F VOUT
Marking Information
Part Number RT9701CBL RT9701CB Marking AH C0
* 470F, Low ESR Electrolytic
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RT9701
Pin Description
Pin Name VIN VOUT GND CE Pin Function Power Input Output Voltage Ground Chip Enable
Test Circuits
VIN RT9701 CBL VIN VOUT CIN
+
VOUT IOUT
VIN GND
VOUT CL
+
RL
IL
Test Circuit 1
VOUT RT9701 CBL VIN VOUT VIN CIN
+
VIN
VIN-SW
Switch Off
VOUT GND CL
+
RL
Test Circuit 2
VIN RT9701 CB VIN
+ VCE
VOUT IOUT VOUT GND VOUT CL
+
CE
CIN
RL
IL
On 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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RT9701
Function Block Diagram
CE Bias Current Limit RS VIN (VIN)
Charge Pump Oscillator
Control NMOSFET
(VOUT) VOUT GND
Thermal Detection
Absolute Maximum Ratings
Supply Voltage Chip Enable Power Dissipation, PD @ TA = 25C SOT-25 Operating Junction Temperature Range Storage Temperature Range Package Thermal Resistance SOT-25, JA VOUT ESD Level HBM (Human Body Mode) MM (Machine Mode) 8KV 800V 250C /W 0.25W -20C ~ 100C -65C ~ 150C 7V -0.3V ~ 7V
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RT9701
Electrical Characteristics
(VIN = 5V, CIN = COUT = 1F, TA = 25C, unless otherwise specified) Parameter Input Voltage Range Output NMOFET RDS(ON) Supply Current Output Turn-On Rising Time Current Limit Threshold Short-circuit Fold Back Current CE Input High Threshold CE Input Low Threshold Shutdown Supply Current Output Leakage Current VIN Under Voltage Lockout VIN Under Voltage Hysteresis Thermal Limit Thermal Limit Hysteresis TSD TSD RT9701CB RT9701CB RT9701CB RT9701CB IOFF UVLO CE = "0" ILEAKAGE CE = "0", VOUT = 0V TR ILIMIT IOS RT9701CBL RT9701CB Symbol VIN RDS(ON) IL = 1A IL = 1A VIN = 3V VIN = 5V RL = 10, 90% Settling RL = 2 VOUT = 0V, measured prior to thermal shutdown Test Conditions Min 2.2 -----1.1 -2.0 ---1.3 ---Typ -100 105 19 23 400 1.5 1.0 --0.1 0.5 1.8 100 130 20 Max 6 130 135 40 45 -2 --0.8 1 10 ----Units V m A S A A V V A A V mV C C
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RT9701
Typical Operating Charateristics
40 35
Supply Current vs. Temp.
VIN = 5V
40 35
Supply Current vs. Voltage
TA Ta = 25 C
Quiessent Current ( A)
30 25 20 15 10 5 0 -40 -20 0 20 40 60 80 100 120
Quiescent Current ( A)
30 25 20 15 10 5 0 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
Temperature (C)
VIN Voltage (V) Voltage (V)
On-Resistance vs. Temp.
160 140 VIN = 5V 160 140
On-Resistance vs. Voltage
Ta 25CC TA == 25 RT9701CBL RT9701CBL
120 100 80 60 40 20 0 -40 -20 0 20 40 60 80 100 120 RT9701CB RT9701CBL
On-Resistance (mOhm) )
On-Resistance (m ))
120 100 80 60 40 20 0 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
Temperature (C) C)
Voltage (V) VIN Voltage (V)
Current Limit vs. Temp.
2.20 2.00 1.80
Current Limit vs. Voltage
1.58
VIN = 5V
TA = 25C
Current Limit (A)
1.60 1.40 1.20 1.00 0.80 0.60 -40 -20 0 20 40 60 80 100 120
Current Limit (A)
1.80
1.35 1.13 0.90 0.68 0.45 0.23 0.00 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
Temperature ( C) C)
VVoltage (V)(V) IN Voltage
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RT9701
Short Circuit Current vs. Temp.
1400 1950
Short Circuit Current vs. Voltage
Ta TA = 25 C Short Circuit Current (mA)
1700 1450 1200 950 700 450 200
1300
VIN = 5V
Short Circuit Current (mA)
1200 1100 1000 900 800 700 600 500 -40 -20 0 20 40 60 80 100 120
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
C) Temperature ( C)
VVoltage (V)(V) IN Voltage
CE Threshold vs. Temp.
2.4 2.4
CE Threshold vs. Voltage
2.0
VIN = 5V
2.0
CE Threshold (V)
CE Threshold (V)
1.6
1.6 1.2 0.8 0.4 0.0
Rising Falling
Rising
1.2 0.8 0.4 0.0 -40 -20 0 20 40 60
Falling
TA = 25 C
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
Temperature (C)
80 100 120 *Test Circuit 3
VVoltage (V)(V) IN Voltage
*Test Circuit 3
Turn On Rising Time vs. Temp.
720
Turn Off Falling Time vs. Temp.
140
Turn-On Rising Time ( S) S)
630 540 450 360 270 180 90 0 -40 -20 0 20 40
VIN = 5V
VIN = 5V
Turn-Off Falling Time ( S)
120 100 80 60 40 20 0 -40 -20 0
RL = 30 CL = 1 F Ceramic
60
RL = 30 CL = 1F Ceramic
20 40 60 80 100 120
Temperature (C)
80 100 120 *Test Circuit 3
Temperature ( C)
*Test Circuit 3
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RT9701
Shutdown Supply Current vs. Temp.
0.9 3.5
Turn-Off Leakage Current vs. Temp.
Turn-Off Leakage Current ( A)
3.0 2.5 2.0 1.5 1.0 0.5 0.0
Turn-Off Supply Current ( A)
VIN = 5V
0.8 0.6 0.5 0.3 0.2 0.0 -40 -20 0 20 40 60
VIN = 5V
Temperature (C)
80 100 120 *Test Circuit 3
-40
-20
0
20
40
60
Temperature ( C)
80 100 120 *Test Circuit 3
UVLO Threshold vs. Temp.
3.50 3.00
Inrush Current Response
VIN = 5V
UVLO Threshold (V)
2.50 2.00 1.50 1.00 0.50 0.00 -40 -20 0 20 40 60 80 100 120
T T T
CL = 100F CL = 33F
CL = 1F
3 2> 4
IL = 1A/Div OUT =1A/Div Temperature ( C)
VIN 1, RL = 1 ohm RL == 5V,VIN = 5V Time (100S/Div) 100S/Div
Turn-On Response
CH1 CH1
1>
Turn-Off Response
RL = 30 , CL = 1F
T T
1>
T
CH2
2>
T T
CH3 CH2
2>
T
T T
CH1: VCE : 5V/Div CH2: VOUT : 1V/Div
3>
RL = 30 , CL = 1F
*Test Circuit 3
CH1: VCE : 5V/Div CH2: IOUT : 100mA/Div; CH3: VOUT : 2V/Div Time (50S/Div)
*Test Circuit 3
Time (100S/Div)
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RT9701
UVLO at Rising
CH1 CH2
UVLO at Falling
T
CH1
1>
T
T T
CH2
2>
T T
CH1: VIN : 1V/Div CH2: VOUT : 1V/Div RL = 30 , CL = 1F Time (500S/Div)
1>
2>
CH1: VIN : 1V/Div CH2: VOUT : 1V/Div
RL = 30 , CL = 1F
*Test Circuit 2
Time (10mS/Div)
Inrush Short Circuit Response
Soft-start Short Circuit Response
T
VDROP =1.2V, depend on CIN ESR IPEAK : depend on ESR & ESL
1> CH1 1 CH1>
T
CH2> 2
T T
CH1 : VIN : 2V/Div CH2 : IL : 10A/Div C IN = 1F C L = 1000F 25S/Div
CH2 > 2
T T
CH1 : VIN : 2V/Div CH2 : IOUT : 1A/Div CIN = 1F 50S/Div
Ramped Load Response
CH1 VOUT = 5V
4.9V
Current Limit Response
T
VOUT = 4.6V CH1
1>
Loading trigger
Current Limit Threshold
1.1A
T T
1>
CH2 CH2: IOUT : 500mA/Div VIN = 5V, CL = 1F 1mS/Div
2>
CH2> 2
CH2: IOUT : 1A/Div ILOAD : 1A/Div
VIN = 5V, CL = 0.1F RL = 1 ohm
5S/Div
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RT9701
Thermal Shut Down Response
T
CH1
1>
CH3 Thermal Shut Down CH2
T T
2>
CH1: VCE : 5V/Div : 1A/Div CH3: IOUT@RL1ohm : 1A/Div 500mA/Div CH2: IOUT@short : 1A/Div 500mA/Div VIN = 5V 50mS/Div Time (50mS/Div)
Functional Description
The RT9701 is a high-side single N-channel switch with active-high enable input. Input and Output VIN (input) is the power supply connection to the circuitry and the drain of the output MOSFET. VOUT (output) is the source of the output MOSFET. In a typical circuit, current flows through the switch from VIN to VOUT toward the load. Both VOUT pins must be short on the board and connected to the load and 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 130C and 20C of hysteresis forces the switch turning off until the die temperature drops to 110C. 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.
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Current Limiting and Short Protection The current limit circuit is designed to protect the system supply, the MOSFET switch and the load from damage caused by excessive currents. The current limit threshold is set internally to allow a minimum of 1.1A through the MOSFET but limits the output current to approximately 1.5A typical. When the output is short to ground, it will limit to a constant current 1A until thermal shutdown or short condition removed.
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RT9701
Applications Information
RT9701CBL VIN CIN 1 F VIN VIN GND COUT VOUT VOUT VOUT1 COUT VOUT2
Ferrite beads in series with all power and ground lines are recommended to eliminate or significantly reduce EMI. In selecting a ferrite bead, the DC resistance of the wire used must be kept to a minimum to reduce the voltage drop. Reverse current preventing The output MOSFET and driver circuitry are also 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 such condition, disable the switch (RT9701CB) or connect VIN to a fixed voltage under 1.3V.
CIN = 1 F, COUT = 470F (Low ESR) on M/B CIN = 1 F, COUT = 330F (Low ESR) on Notebook CIN = 10 F, C OUT = 1 F on USB device
Fig. 1 High Side Power Switch
RT9701CB VIN CIN VIN CE GND COUT ON VCE OFF COUT VOUT VOUT VOUT1 VOUT2
Layout and Thermal Dissipation Place the switch as close to the USB connector as possible. Keep all traces as short as possible to reduce the effect of undesirable parasitic inductance. Place the output capacitor and ferrite beads as close to the USB connector as possible. If ferrite beads are used, use wires with minimum resistance and large solder pads to minimize connection resistance. If the package is with dual VOUT or VIN pins, short both the same function pins as Fig.1 or Fig.2 to reduce the internal turn-on resistance. If the output power will be delivered to two individual ports, it is specially necessary to short both VOUT pin at the switch output side in order to protect the switch when each port are plug-in separately. 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.
Fig. 2 High Side Power Switch with Chip Enable Control
Filtering To limit the input voltage drop during hot-plug events, connect a 1F ceramic capacitor from VIN to GND. However, higher capacitor values will further reduce the voltage drop at the input. Connect a sufficient capacitor from VOUT to GND. This capacitor helps to prevent inductive parasitics 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 1F capacitor from VOUT to GND is recommended and 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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RT9701
Package Information
D
C
B
b
A e L
H
A1
Symbol A A1 B b C D e H L
Dimensions In Millimeters Min 0.889 0.000 1.397 0.356 2.591 2.692 0.838 0.102 0.356 Max 1.295 0.152 1.803 0.559 2.997 3.099 1.041 0.254 0.610
Dimensions In Inches Min 0.035 0.000 0.055 0.014 0.102 0.106 0.033 0.004 0.014 Max 0.051 0.006 0.071 0.022 0.118 0.122 0.041 0.010 0.024
SOT- 25 Surface Mount Package
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RT9701
RICHTEK TECHNOLOGY CORP.
Headquarter
6F, No. 35, Hsintai Road, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5510047 Fax: (8863)5537749
RICHTEK TECHNOLOGY CORP.
Taipei Office (Marketing)
8F-1, No. 137, Lane 235, Paochiao Road, Hsintien City Taipei County, Taipei, R.O.C. Tel: (8862)89191466 Fax: (8862)89191465
Email: marketing@richtek-ic.com.tw
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