RT9701B 100mΩ Ω Power Distribution Switches General Description Features The RT9701B is an integrated 100mΩ power switch for self-powered and bus-powered Universal Series Bus (USB) applications. A built-in charge pump is used to drive the N-MOSFET that is free of parasitic body diode to z eliminate any reversed current flow across the switch when it is powered off. Its low quiescent current (23uA) and small package (SOT-23-5) is particularly suitable in battery-powered portable equipment. z 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. z z z z z z z z Applications z Ordering Information RT9701B z z z Package Type B : SOT-23-5 BL : SOT-23-5 (L-Type) Lead Plating System P : Pb Free G : Green (Halogen Free and Pb Free) 100mΩ Ω Typ. High-Side N-MOSFET Guaranteed 1.1A Continuous Current 1.5A Current Limit Small SOT-23-5 Package Minimizes Board Space Soft Start Thermal Protection Low 23uA Supply Current Wide Input Voltage Range : 3.5V to 6V UL Approved - #E219878 RoHS Compliant and 100% Lead (Pb)-Free z Battery-Powered Equipment Motherboard USB Power Switch USB Device Power Switch Hot-Plug Power Supplies Battery-Charger Circuits Pin Configurations (TOP VIEW) VOUT EN 5 4 Note : Richtek products are : ` RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. ` 2 3 VOUT GND VIN Suitable for use in SnPb or Pb-free soldering processes. SOT-23-5 Marking Information For marking information, contact our sales representative directly or through a Richtek distributor located in your area. VOUT VIN 5 4 2 3 VOUT GND VIN SOT-23-5 (L-Type) DS9701B-06 April 2011 www.richtek.com 1 RT9701B Typical Application Circuit VIN CIN 1uF VIN RT9701B VOUT VIN VOUT VOUT * COUT 470uF GND * 470uF, Low ESR Electrolytic Test Circuits IIN VIN_SW VIN + EN VOUT VOUT + CIN 1uF IL IOUT RT9701B VIN VOUT GND COUT IL RL Chip Enable Functional Pin Description Pin Name Pin Function VIN Power Input Voltage VOUT Output Voltage GND Ground EN Chip Enable (Active High) Function Block Diagram VIN EN Current Limit Bias Charge Pump Control NMOSFET RS (VIN) (VOUT) VOUT Oscillator www.richtek.com 2 Thermal Detection GND DS9701B-06 April 2011 RT9701B Absolute Maximum Ratings z z z z z z z z (Note 1) Supply Voltage ------------------------------------------------------------------------------------------------------------Chip Enable ----------------------------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C SOT-23-5 -------------------------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 3) SOT-23-5, θJA --------------------------------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------Operating Junction Temperature Range -----------------------------------------------------------------------------Storage Temperature Range -------------------------------------------------------------------------------------------ESD Susceptibility (Note 2) HBM (Human Body Mode) ---------------------------------------------------------------------------------------------MM (Machine Mode) ------------------------------------------------------------------------------------------------------ 7V −0.3V to 7V 0.4W 250°C /W 260°C −20°C to 100°C −65°C to 150°C 8kV 700V Electrical Characteristics (VIN = 5V, CIN = COUT = 1μF, TA = 25°C, unless otherwise specified) Parameter Symbol Input Voltage Range Output NMOSFET RDS(ON) Test Conditions Min Typ Max Units 3.5 -- 6 V IL = 1A -- 85 100 IL = 1A -- 87 100 VIN = 5V -- 23 45 μA -- 400 -- μs 1.1 1.5 2 A -- 1.0 -- A VIN RT9701BCBL RT9701BCB RDS(ON) Quiescent Current Output Turn-On Rising Time TR RL = 10Ω, 90% Settling Current Limit Threshold ILIM RL = 2Ω Short-circuit Fold Back Current IOS VOUT = 0V, measured prior to thermal shutdown mΩ EN Input High Threshold RT9701BCB 2.0 -- -- V EN Input Low Threshold RT9701BCB -- -- 0.8 V Shutdown Supply Current RT9701BCB IOFF EN = “0” -- 0.1 1 μA Output Leakage Current RT9701BCB ILEAKAGE EN = “0”, VOUT = 0V -- 0.5 10 μA 2.8 3 -- V -- 100 -- mV VIN Under Voltage Lockout UVLO VIN Under Voltage Hysteresis Thermal Limit TSD -- 130 -- °C Thermal Limit Hysteresis ΔTSD -- 20 -- °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 is recommended. Note 3. θJA is measured in the natural convection at T A = 25°C on a low effective thermal conductivity test board of JEDEC 51-3 thermal measurement standard. DS9701B-06 April 2011 www.richtek.com 3 RT9701B Typical Operating Characteristics (Refer to Test Circuit) Quiescent Current vs. Temperature 40 Quiescent Current vs. Input Voltage 40 VIN = 5V Quiescent Current (uA) Quiescent Current (uA) TA = 25°C 35 35 30 25 20 15 10 30 25 20 15 10 5 5 0 0 -20 -5 10 25 40 55 70 85 3.5 100 3.8 4.0 4.3 On-Resistance vs. Temperature 200 5.0 5.3 5.5 5.8 6.0 On-Resistance vs. Input Voltage VIN = 5V TA = 25°C 95 150 On-Resistance (mΩ) On-Resistance (mΩ) 4.8 100 175 RT9701BCBL 125 100 RT9701BCB 75 50 25 0 90 RT9701BCB 85 RT9701BCBL 80 75 70 -20 -5 10 25 40 55 70 85 100 3.5 3.8 4.0 4.3 Temperature (°C) (℃) 4.5 4.8 5.0 5.3 5.5 5.8 6.0 Input Voltage(V) Current Limit vs. Temperature 2.20 Current Limit vs. Input Voltage 1.80 VIN = 5V 2.00 1.58 1.80 1.35 Current Limit (A) Current Limit (A) 4.5 Input Voltage (V) Temperature (°C) 1.60 1.40 1.20 1.00 TA = 25°C 1.13 0.90 0.68 0.45 0.23 0.80 0.00 0.60 -20 -5 10 25 40 55 Temperature (°C) www.richtek.com 4 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 Input Voltage (V) DS9701B-06 April 2011 RT9701B Short Circuit Current vs. Input Voltage Short Circuit Current vs. Temperature 1950 1.950 VIN = 5V 1300 1.3 Short Circuit Current (A) Short Circuit Current (A) 1 1400 1.4 1200 1.2 1100 1.1 1000 1.0 900 0.9 800 0.8 700 0.7 TA = 25°C 1700 1.7 1450 1.45 1200 1.2 950 0.95 700 0.7 450 0.45 600 0.6 200 0.2 0.5 500 -20 -5 10 25 40 55 70 85 3.5 100 3.8 4.0 4.3 Temperature (°C) 5.0 5.3 5.5 5.8 6.0 EN Threshold vs. Input Voltage EN Threshold vs. Temperature 2.4 VIN = 5V TA =25°C 2.0 EN Threshold (V) 2.0 EN Threshold (V) 4.8 Input Voltage (V) 2.4 1.6 Rising 1.2 Falling 0.8 1.6 Rising 1.2 Falling 0.8 0.4 0.4 0.0 0.0 -20 -5 10 25 40 55 70 85 3.5 100 3.8 4.0 4.3 Temperature (°C) 4.5 4.8 5.0 5.3 5.5 5.8 6.0 Input Voltage (V) Turn On Rising Time vs. Temperature 400 Shutdown Supply Current vs. Temperature 0.9 VIN = 5V Shutdown Supply Current (uA) Turn On Rising Time (us) 4.5 350 300 250 200 150 100 VIN = 5V 0.8 0.6 0.5 0.3 0.2 0.0 -20 -5 10 25 40 55 Temperature (°C) DS9701B-06 April 2011 70 85 100 -20 -5 10 25 40 55 70 85 100 Temperature (°C) www.richtek.com 5 RT9701B UVLO Threshold vs. Temperature 4.5 VIN = 5V VIN = 5V 3.0 UVLO Threshold (V) Turn-Off Leakage Current (uA) A Turn-Off Leakage Current vs. Temperature 3.5 2.5 2.0 1.5 1.0 0.5 0.0 4 3.5 3 2.5 2 -20 -5 10 25 40 55 70 85 100 -20 -5 Temperature (°C) 10 25 40 55 70 85 100 Temperature (°C) Turn - Off Response Turn - On Response VIN = 5V VIN = 5V CH1 CH1 CH1: VEN: 5V/Div CH2: IL: 100mA/Div CH3: VOUT: 2V/Div CH2 CH1: VEN: 5V/Div CH2: VOUT: 1V/Div RL = 10Ω, COUT = 1uF CH2 CH3 Time (100us/Div) Time (50us/Div) UVLO at Rising UVLO at Falling CH1: VIN: 1V/Div CH2: VOUT: 1V/ Div RL = 30Ω, COUT = 1uF CH1: VIN: 1V/Div CH2: VOUT: 1V/Div RL = 30Ω, COUT = 1uF CH1 CH1 CH2 CH2 Time (500us/Div) www.richtek.com 6 RL = 30Ω, COUT = 1uF Time (10ms/Div) DS9701B-06 April 2011 RT9701B Inrush Short Circuit Response Soft - start Short Circuit Response CH1: VIN: 2V/Div CH1: VIN: 2V/Div VDROP=1.2V, depend on CIN ESR IPEAK : depend on ESR & ESL CH1 CH1 CH2: IL: 1A/Div CH2 CH1 CIN = 1uF, COUT = 1000uF CH2: IL: 1A/Div CH2 CIN = 1uF Time (25us/Div) Time (50us/Div) Ramped Load Response Thermal Shut Dowm Response VOUT = 4.6V VOUT = 4.9V CH1 Current Limit Threshold CH3 Thermal Shut Down 1.1A CH2 CH2 CH2: IOUT: 500mA/Div CH1: VEN = 5V/Div, CH3:IOUT@RL1Ω:1A/Div CH2: IOUT@short:1A/DiV, VIN = 5V VIN = 5V, COUT = 1uF Time (1ms/Div) Time (50ms/Div) Current Limit Response Current Limit Response COUT = 1uF COUT = 1uF COUT = 33uF COUT = 100uF COUT = 33uF COUT = 100uF IL (1A/Div) IOUT (1A/Div) VIN = 5V, RL = 1Ω Time (100us/Div) DS9701B-06 April 2011 VIN = 5V, RL = 1Ω Time (100us/Div) www.richtek.com 7 RT9701B Current Limit Response Loading trigger CH1 CH2 CH2: IOUT: 1A/Div VIN = 5V, COUT = 0.1uF RL = 1Ω Time (5us/Div) www.richtek.com 8 DS9701B-06 April 2011 RT9701B 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 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. 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 1μF 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 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. 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. Current Limiting and Short Protection Layout and Thermal Dissipation Under-voltage Lockout 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. z z z 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. Filtering To limit the input voltage drop during hot-plug events, connect a 1μF ceramic capacitor from VIN to GND. However, higher capacitor values will further reduce the voltage drop at the input. DS9701B-06 April 2011 www.richtek.com 9 RT9701B z z 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. RT9701BCBL VIN VOUT VIN VIN CIN 1uF VOUT VOUT2 VOUT1 GND COUT 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 VOUT GND Chip Enable VOUT1 COUT VOUT2 COUT Figure 2. High Side Power Switch with Chip Enable Control www.richtek.com 10 DS9701B-06 April 2011 RT9701B Outline Dimension H D L B C b A A1 e Symbol 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 0.080 0.254 0.003 0.010 L 0.300 0.610 0.012 0.024 SOT-23-5 Surface Mount Package Richtek Technology Corporation Richtek Technology Corporation Headquarter Taipei Office (Marketing) 5F, No. 20, Taiyuen Street, Chupei City 5F, No. 95, Minchiuan Road, Hsintien City Hsinchu, Taiwan, R.O.C. Taipei County, Taiwan, R.O.C. Tel: (8863)5526789 Fax: (8863)5526611 Tel: (8862)86672399 Fax: (8862)86672377 Email: [email protected] Information that is provided by Richtek Technology Corporation is believed to be accurate and reliable. Richtek reserves the right to make any change in circuit design, specification or other related things if necessary without notice at any time. No third party intellectual property infringement of the applications should be guaranteed by users when integrating Richtek products into any application. No legal responsibility for any said applications is assumed by Richtek. DS9701B-06 April 2011 www.richtek.com 11