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Preliminary
RT9701B
100m Power Distribution Switches
General Description
The RT9701B 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 MOSFET that is free of parasitic body diode to eliminate any reversed current flow across the switch when it is powered off. Its low quiescent current (23A) and small package (SOT-23-5) 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 Guaranteed 1.1A Continuous Current 1.5A Current Limit Small SOT-23-5 Package Minimizes Board Space Soft Start Thermal Protection Low 23A Supply Current Wide Input Voltage Range : 3.5V to 6V UL Approved - #E219878 RoHS Compliant and 100% Lead (Pb)-Free
Applications
Battery-Powered Equipment Motherboard USB Power Switch USB Device Power Switch Hot-Plug Power Supplies Battery-Charger Circuits
Ordering Information
RT9701B Package Type B : SOT-23-5 BL : SOT-23-5 (L-Type) Operating Temperature Range P : Pb Free with Commercial Standard G : Green (Halogen Free with Commercial Standard)
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.
VOUT GND VIN
1 2 3
5
VOUT
VOUT GND
1 2 3
5
VOUT
4
EN
VIN
4
VIN
SOT-23-5
SOT-23-5 (L-Type)
Marking Information
For marking information, contact our sales representative directly or through a RichTek distributor located in your area, otherwise visit our website for detail.
Typical Application Circuit
VIN CIN 1uF VIN VIN GND RT9701B VOUT VOUT VOUT * COUT 470uF
* 470uF, Low ESR Electrolytic
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RT9701B
Test Circuits
VIN + CIN 1uF
Preliminary
VIN_SW
IIN
RT9701B VIN VOUT EN GND VOUT
IOUT
+
IL
VOUT
COUT
RL
IL
Chip Enable
Functional Pin Description
Pin Name VIN VOUT GND EN Pin Function Power Input Voltage Output Voltage Ground Chip Enable (Active High)
Function Block Diagram
EN Bias Current Limit RS VIN (VIN)
Charge Pump
Control NMOSFET
(VOUT) VOUT
Oscillator
Thermal Detection
GND
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Preliminary Absolute Maximum Ratings
(Note 1)
RT9701B
7V
Supply Voltage ------------------------------------------------------------------------------------------------------------Chip Enable ----------------------------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25C SOT-23-5 -------------------------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 3) SOT-23-5, JA --------------------------------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------Operating Junction Temperature Range -----------------------------------------------------------------------------Storage Temperature Range -------------------------------------------------------------------------------------------ESD Susceptibility (Note 2) HBM (Human Body Mode) ---------------------------------------------------------------------------------------------MM (Machine Mode) ------------------------------------------------------------------------------------------------------
-0.3V to 7V
0.4W 250C /W 260C -20C to 100C -65C to 150C 8kV 700V
Electrical Characteristics
(VIN = 5V, CIN = COUT = 1F, TA = 25C, unless otherwise specified)
Parameter Input Voltage Range Output NMOSFET RDS(ON) Quiescent Current Output Turn-On Rising Time Current Limit Threshold Short-circuit Fold Back Current EN Input High Threshold EN Input Low Threshold Shutdown Supply Current Output Leakage Current VIN Under Voltage Lockout VIN Under Voltage Hysteresis Thermal Limit Thermal Limit Hysteresis RT9701BCB RT9701BCB RT9701BCB RT9701BCB RT9701BCBL RT9701BCB
Symbol VIN RDS(ON)
Test Conditions
Min 3.5
Typ -85 87 23 400 1.5 1.0 --0.1 0.5 3 100 130 20
Max 6 100 100 45 -2 --0.8 1 10 -----
Units V m A s A A V V A A V mV C C
IL = 1A IL = 1A VIN = 5V RL = 10, 90% Settling RL = 2 VOUT = 0V, measured prior to thermal shutdown
----1.1 -2.0 --
TR ILIM IOS
IOFF UVLO
EN = "0"
--2.8 ----
ILEAKAGE EN = "0", VOUT = 0V
TSD TSD
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. JA is measured in the natural convection at T A = 25C on a low effective thermal conductivity test board of JEDEC 51-3 thermal measurement standard.
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RT9701B
(Refer to Test Circuit)
Preliminary
Typical Operating Characteristics
Quiescent Current vs. Temperature
40 35
Quiescent Current vs. Input Voltage
40 35
VIN = 5V
TA = 25C
Quiescent Current (uA)
Quiescent Current (uA)
30 25 20 15 10 5 0 -20 -5 10 25 40 55 70 85 100
30 25 20 15 10 5 0 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0
Temperature (C)
Input Voltage (V)
On-Resistance vs. Temperature
200 175
On-Resistance vs. Input Voltage
100 95
VIN = 5V
TA = 25C
On-Resistance (m)
RT9701BCBL
On-Resistance (m)
150 125 100 75 50 25 0 -20 -5 10 25 40 55
90 85
RT9701BCB
RT9701BCB
RT9701BCBL
80 75 70
70
85
100
3.5
3.8
4.0
4.3
4.5
4.8
5.0
5.3
5.5
5.8
6.0
Temperature (C) ()
Input Voltage(V)
Current Limit vs. Temperature
2.20 2.00
Current Limit vs. Input Voltage
1.80 1.58 1.35
VIN = 5V
TA = 25C
Current Limit (A)
1.80
Current Limit (A)
1.60 1.40 1.20 1.00 0.80 0.60 -20 -5 10 25 40 55 70 85 100
1.13 0.90 0.68 0.45 0.23 0.00 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 5.8 6.0
Temperature (C)
Input Voltage (V)
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Preliminary
RT9701B
Short Circuit Current vs. Input Voltage
1950 1.950
Short Circuit Current vs. Temperature
1400 1.4
VIN = 5V
TA = 25C
Short Circuit Current (A) 1
1300 1.3 1200 1.2 1100 1.1 1000 1.0 900 0.9 800 0.8 700 0.7 600 0.6
Short Circuit Current (A)
1700 1.7 1450 1.45 1200 1.2 950 0.95 700 0.7 450 0.45 200 0.2
0.5 500
-20 -5 10 25 40 55 70 85 100
3.5
3.8
4.0
4.3
4.5
4.8
5.0
5.3
5.5
5.8
6.0
Temperature (C)
Input Voltage (V)
EN Threshold vs. Temperature
2.4 2.0
EN Threshold vs. Input Voltage
2.4 2.0
VIN = 5V
TA =25C
EN Threshold (V)
EN Threshold (V)
1.6
1.6 1.2 0.8 0.4 0.0
Rising
Rising
1.2 0.8 0.4 0.0 -20 -5 10 25 40 55 70 85 100
Falling
Falling
3.5
3.8
4.0
4.3
4.5
4.8
5.0
5.3
5.5
5.8
6.0
Temperature (C)
Input Voltage (V)
Turn On Rising Time vs. Temperature
400 350 300 250 200 150 100 -20 -5 10 25 40 55 70 85 100
Shutdown Supply Current vs. Temperature
0.9
VIN = 5V
Shutdown Supply Current (uA)
VIN = 5V
0.8 0.6 0.5 0.3 0.2 0.0 -20 -5 10 25 40 55 70 85 100
Turn On Rising Time (us)
Temperature (C)
Temperature (C)
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RT9701B
Preliminary
Turn-Off Leakage Current vs. Temperature
A
3.5
UVLO Threshold vs. Temperature
4.5
VIN = 5V
3.0 2.5 2.0 1.5 1.0 0.5 0.0 -20 -5 10 25 40 55 70 85 100
VIN = 5V
Turn-Off Leakage Current (uA)
UVLO Threshold (V)
4
3.5
3
2.5
2 -20 -5 10 25 40 55 70 85 100
Temperature (C)
Temperature (C)
Turn - On Response
VIN = 5V VIN = 5V
Turn - Off Response
CH1: VEN: 5V/Div CH2: IL: 100mA/Div CH3: VOUT: 2V/Div
CH1
CH1
CH2
CH2
CH1: VEN: 5V/Div CH2: VOUT: 1V/Div RL = 10, COUT = 1uF
CH3
RL = 30, COUT = 1uF
Time (100us/Div)
Time (50us/Div)
UVLO at Rising
CH1: VIN: 1V/Div CH2: VOUT: 1V/Div RL = 30, COUT = 1uF
UVLO at Falling
CH1: VIN: 1V/Div CH2: VOUT: 1V/ Div RL = 30, COUT = 1uF
CH1 CH2
CH1 CH2 Time (10ms/Div)
Time (500us/Div)
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Preliminary
RT9701B
Soft - start Short Circuit Response
CH1: VIN: 2V/Div
Inrush Short Circuit Response
CH1: VIN: 2V/Div VDROP=1.2V, depend on CIN ESR IPEAK : depend on ESR & ESL
CH1
CH1
CH2: IL: 1A/Div
CH2
CH2: IL: 1A/Div
CIN = 1uF, COUT = 1000uF
CH2
CIN = 1uF
Time (25us/Div)
Time (50us/Div)
Ramped Load Response
CH1
VOUT = 4.9V Current Limit Threshold VOUT = 4.6V
Thermal Shut Dowm Response
CH1
CH3
1.1A
Thermal Shut Down
CH2 CH2
CH2: IOUT: 500mA/Div VIN = 5V, COUT = 1uF CH1: VEN = 5V/Div, CH3:IOUT@RL1:1A/Div CH2: IOUT@short:1A/DiV, VIN = 5V
Time (1ms/Div)
Time (50ms/Div)
Current Limit Response
Current Limit Response
COUT = 1uF COUT = 33uF COUT = 100uF
COUT = 1uF COUT = 33uF COUT = 100uF
IOUT (1A/Div)
VIN = 5V, RL = 1
IL (1A/Div)
VIN = 5V, RL = 1
Time (100us/Div)
Time (100us/Div)
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RT9701B
Current Limit Response
Preliminary
CH1
Loading trigger
CH2
CH2: IOUT: 1A/Div VIN = 5V, COUT = 0.1uF RL = 1
Time (5us/Div)
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DS9701B-04 March 2007
Preliminary Application Information
The RT9701B is a high-side single N-Channel MOSFET 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 3V (typical). If input voltage drops below 3V (typical), UVLO shuts off the MOSFET switch. 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. 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.
DS9701B-04 March 2007
RT9701B
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 hot-detachment. It is also necessary for meeting the USB specification during hot plug-in operation. If RT9701B 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 ESR. A lower ESR on this capacitor can get a lower IR drop during the operation. 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 (RT9701BCB) or connect VIN to a fixed voltage under UVLO. 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 ot capacitor and ferrite beads asclose to the USB connector as possible. If ferrite beads are used, use wires with minimum resistance and large solder pads to minimize connection resistance.
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RT9701B
Preliminary
If the package is with dual VOUT or VIN pins, short both the same function pins as Figure 1 or Figure 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 power-bus planes connected to VIN and VOUT and a ground plane in contact with the device will help dissipate additional heat.
VIN CIN 1uF
RT9701BCBL VIN VOUT VIN GND COUT VOUT VOUT1
VOUT2 COUT
CIN = 1uF, COUT = 470uF (Low ESR) on M/B CIN = 1uF, COUT = 330uF (Low ESR) on Notebook CIN = 10uF, COUT = 1uF on USB device
Figure 1. High Side Power Switch
VIN
CIN
RT9701BCB VIN VOUT EN GND VOUT VOUT1 COUT
VOUT2 COUT
Chip Enable
Figure 2. High Side Power Switch with Chip Enable Control
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DS9701B-04 March 2007
Preliminary Outline Dimension
RT9701B
H D L C B
b A A1 e
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 0.080 0.300 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 0.003 0.012 Max 0.051 0.006 0.071 0.022 0.118 0.122 0.041 0.010 0.024
SOT-23-5 Surface Mount Package
Richtek Technology Corporation
Headquarter 5F, No. 20, Taiyuen Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Fax: (8863)5526611
Richtek Technology Corporation
Taipei Office (Marketing) 8F, No. 137, Lane 235, Paochiao Road, Hsintien City Taipei County, Taiwan, R.O.C. Tel: (8862)89191466 Fax: (8862)89191465 Email: marketing@richtek.com
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