RT9724GB

® RT9724 100mΩ Ω, 2A Slew Rate Controlled Load Switch General Description Features The RT9724 is a cost-effective, low-voltage, single N-MOSFET high-side Power Switch IC. Low switch-on resistance (typ. 100mΩ) and low supply current (typ. 50uA) are realized in this IC. The RT9724 integrates an overcurrent protection circuit, a short fold back circuit, a thermal shutdown circuit and an under-voltage lockout circuit for overall protection. Besides, a slew rate controlled function is embedded for turn-on rising time control. The RT9724 is available in SOT-23-5 and WDFN8L 2x2 package. z z z z z z z z z 100mΩ Ω (typ.) N-MOSFET Switch Operating Range : 2.7V to 5.5V Reverse Blocking Current Under Voltage Lockout Thermal Protection with Foldback Over Current Protection Short Circuit Protection Slew Rate Limited Turn-On Time 3ms (5V) RoHS Compliant and Halogen Free Applications Ordering Information RT9724 z z Package Type B : SOT-23-5 QW : WDFN-8L 2x2 (W-Type) Lead Plating System G : Green (Halogen Free and Pb Free) z z z z Cellular Phones Digital still Camera Hot swap Supplies Notebook Computers Personal Communication Devices Personal Digital Assistants Note : Richtek products are : ` ` Pin Configurations RoHS compliant and compatible with the current require- (TOP VIEW) ments of IPC/JEDEC J-STD-020. VIN VIN 5 4 Suitable for use in SnPb or Pb-free soldering processes. 2 Marking Information RT9724GB EN GND VOUT SOT-23-5 1Y= : Product Code DNN : Date Code NC VOUT EN GND RT9724GQW GV : Product Code GVW 1 2 3 4 GND 1Y=DNN 3 9 8 7 6 5 VIN VIN VIN VIN WDFN-8L 2x2 W : Date Code Copyright © 2012 Richtek Technology Corporation. All rights reserved. DS9724-02 July 2012 is a registered trademark of Richtek Technology Corporation. www.richtek.com 1 RT9724 Typical Application Circuit 2.7V to 5.5V CIN 1µF Chip Enable VIN VOUT RT9724 EN COUT 0.1µF Load GND Functional Pin Description Pin No. SOT-23-5 WDFN-8L 2x2 1 3 2 Pin Name EN Chip Enable (Active High). Ground. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. 4, GND 9 (Exposed Pad) 3 2 4, 5 -- Pin Function VOUT Power-Switch Output. 5, 6, 7, 8 VIN Power Input Voltage. 1 NC No Internal Connection. Function Block Diagram VIN EN Bias UVLO Oscillator Charge Pump Current Limiting Gate Control Output Voltage Detection Thermal Protection VOUT Auto Discharge GND Copyright © 2012 Richtek Technology Corporation. All rights reserved. www.richtek.com 2 is a registered trademark of Richtek Technology Corporation. DS9724-02 July 2012 RT9724 Absolute Maximum Ratings z z z z z z z (Note 1) Supply Voltage, VIN ------------------------------------------------------------------------------------------------------ 6V Enable Input Voltage, EN ------------------------------------------------------------------------------------------------ −0.3V to 6V Power Dissipation, PD @ TA = 25°C SOT-23-5 -------------------------------------------------------------------------------------------------------------------WDFN-8L 2x2 -------------------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2) SOT-23-5, θJA -------------------------------------------------------------------------------------------------------------WDFN-8L 2x2, θJA -------------------------------------------------------------------------------------------------------Junction Temperature ----------------------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------ESD Susceptibility (Note 3) HBM (Human Body Model) ---------------------------------------------------------------------------------------------- Recommended Operating Conditions 0.458W 0.833W 218.1°C/W 120°C/W 150°C 260°C 4kV (Note 4) Supply Voltage, VIN -----------------------------------------------------------------------------------------------------z Enable Input Voltage, EN -----------------------------------------------------------------------------------------------z Junction Temperature Range -------------------------------------------------------------------------------------------z Ambient Temperature Range -------------------------------------------------------------------------------------------z 2.7V to 5.5V 0V to 5.5V −40°C to 100°C −40°C to 85°C Electrical Characteristics (VIN = 5V, CIN = 1μF, COUT = 0.1μF, TA = 25°C, unless otherwise specified) Parameter Symbol Test Conditions Min Typ Max Unit 2.7 -- 5 V 1.3 1.7 2.1 V -- 50 -- mV Operation Voltage VIN Under Voltage Lookout Under Voltage Lockout Hysteresis Quiescent Current VUVLO IQ EN = High -- 50 70 μA Off Supply Current ISHDN EN = Low, VOUT = Open -- -- 1 μA Off Switch Current ILEAKAGE EN = Low, VOUT = 0 -- -- 1 μA On-Resistance RDS(ON) VIN = 3.3V, IOUT = 1.3 A -- 100 120 mΩ Current Limiting ILIM 1.5 2 2.5 A Short Circuit Current ISC_FB 0.4 0.8 1.5 A Thermal shutdown Threshold TSD VIN = 3.3V, VOUT = 2.3V VOUT = 0V, Measured Prior to Thermal Shutdown VOUT > 1V -- 130 -- °C -- 100 -- °C -- 20 -- °C VIN Falling ΔVUVLO VOUT = 0V Hysteresis EN Threshold Voltage Logic-Low VIL VIN = 2.7V to 5.5V -- -- 0.8 V Logic-High VIH VIN = 2.7V to 5.5V 2 -- -- V IEN VEN = 5.5V -- -- 1 μA Enable Input Leakage Copyright © 2012 Richtek Technology Corporation. All rights reserved. DS9724-02 July 2012 is a registered trademark of Richtek Technology Corporation. www.richtek.com 3 RT9724 Parameter Symbol Test Conditions Min Typ Max Unit Output Turn-On Delay Time TD_ON VIN = 5V, RLOAD = 10Ω -- 60 100 μs Output Turn-On Rise Time TON VIN = 5V, RLOAD = 10Ω 1 3 -- ms Output Turn-Off Delay Time Output Pull-Down Resistance During OFF TD_OFF VIN = 5V, RLOAD = 10Ω -- 4 10 μs -- 150 -- Ω RDISCHARGE EN = Low Note 1. Stresses beyond those listed “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and 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 may affect device reliability. Note 2. θJA is measured at TA = 25°C on a high effective thermal conductivity four-layer test board per JEDEC 51-7. Note 3. Devices are ESD sensitive. Handling precaution is recommended. Note 4. The device is not guaranteed to function outside its operating conditions. Copyright © 2012 Richtek Technology Corporation. All rights reserved. www.richtek.com 4 is a registered trademark of Richtek Technology Corporation. DS9724-02 July 2012 RT9724 Typical Operating Characteristics On Resistance vs. Input Voltage 115 On Resistance vs. Temperature 150 EN = 5V, IOUT = 1.5A VIN = VEN = 5V, IOUT = 1.5A 140 On Resistance (mΩ) On Resistance (mΩ) 114 113 112 111 130 120 110 100 90 110 80 2.7 3.1 3.4 3.7 4 4.3 4.6 4.9 5.2 -40 5.5 -20 0 Input Voltage (V) Quiescent Current vs. Input Voltage VEN = 5V, No Load 27 24 21 18 15 80 100 VIN = VEN = 5.5V, No Load 28 26 24 22 3.1 3.4 3.7 4 4.3 4.6 4.9 5.2 5.5 -40 -20 0 Input Voltage (V) 20 40 60 80 100 Temperature (°C) Shutdown Current vs. Input Voltage Shutdown Current vs. Temperature 1 VEN = 0V,No Load VIN = 5.5V, VEN = 0V, No Load 0.9 0.25 Shutdown Current (µA)1 Shutdown Current (µA)1 60 20 2.7 0.30 40 Quiescent Current vs. Temperature 30 Quiescent Current (µA) Quiescent Current (µA) 30 20 Temperature (°C) 0.20 0.15 0.10 0.05 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 0.00 2.7 3.1 3.4 3.7 4 4.3 4.6 4.9 5.2 Input Voltage (V) Copyright © 2012 Richtek Technology Corporation. All rights reserved. DS9724-02 July 2012 5.5 -40 -20 0 20 40 60 80 100 Temperature (°C) is a registered trademark of Richtek Technology Corporation. www.richtek.com 5 RT9724 Output Voltage vs. Output Current 6 UVLO Threshold vs. Temperature 2.1 VIN = 5.5V UVLO Threshold (V) Output Voltage (V) 5 4 VIN = 3.3V 3 2 1 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 Rising 1.7 Falling 1.5 1.3 VEN = 5V VEN = 5V 0 1.9 1.1 2.2 -40 -20 0 Output Current (A) 2 1.2 1.9 1.1 Short Current (A) Current Limit (A) 40 60 80 100 Short Current vs. Input Voltage Current Limit vs. Input Voltage 1.8 1.7 1 0.9 0.8 1.6 VEN = 5V 1.5 2.7 3.1 3.4 3.7 4 4.3 4.6 4.9 5.2 VEN = 5V 0.7 2.7 5.5 3.1 3.4 3.7 4 4.3 4.6 4.9 5.2 5.5 Input Voltage (V) Input Voltage (V) Current Limit vs. Temperature Short Current vs. Temperature 2 1.2 1.9 1.1 Short Current (A) Current Limit (A) 20 Temperature (°C) 1.8 1.7 1 0.9 0.8 1.6 VEN = 5V 1.5 -40 -20 0 20 40 60 80 Temperature (°C) Copyright © 2012 Richtek Technology Corporation. All rights reserved. www.richtek.com 6 100 VIN = VEN = 5V 0.7 -40 -20 0 20 40 60 80 100 Temperature (°C) is a registered trademark of Richtek Technology Corporation. DS9724-02 July 2012 RT9724 Turn On Rising Time vs. Temperature Turn-On Rising Time vs. Input Voltage 5 Turn On Rising Time (ms) Turn-On Rising Time (ms) 4 3.7 3.4 3.1 2.8 2.5 3.1 3.4 3.7 4 4.2 3.8 3.4 VIN = VEN = 5V, RLOAD = 10Ω VEN = 5V, RLOAD = 10Ω 2.7 4.6 3 4.3 4.6 5 5.2 -40 5.5 -20 0 Input Voltage (V) 60 80 100 0.6 Turn Off Delay Time (µs) Turn-Off Delay Time (µs) 40 Turn Off Delay Time vs. Temperature Turn-Off Delay Time vs. Input Voltage 1.2 1 0.8 0.6 0.4 0.2 20 Temperature (°C) VEN = 5V, RLOAD = 10Ω 2.7 3.1 3.4 3.7 4 0.5 0.4 0.3 VEN = 5V, RLOAD = 10Ω 0.2 4.3 4.6 5 5.2 5.5 -40 -20 0 20 40 60 Input Voltage (V) Temperature (°C) Power On from VIN Power On from EN 80 100 VOUT (2V/Div) VIN (2V/Div) VEN (5V/Div) VOUT (2V/Div) VIN = VEN = 5V, No Load Time (5ms/Div) Copyright © 2012 Richtek Technology Corporation. All rights reserved. DS9724-02 July 2012 IOUT (1V/Div) VIN = VEN = 5.5V, RLOAD = 3Ω Time (2.5ms/Div) is a registered trademark of Richtek Technology Corporation. www.richtek.com 7 RT9724 Applications Information The RT9724 is a single N-MOSFET high-side power switches with enable input, optimized for self-powered and bus-powered Universal Serial Bus (USB) applications. The RT9724 is equipped with a charge pump circuitry to drive the internal N-MOSFET switch; the switch's low RDS(ON), 100mΩ, meets USB voltage drop requirements. Under Voltage Lockout Under Voltage Lockout (UVLO) prevents the MOSFET switch from turning on until the input voltage exceeds approximately 1.75V. If input voltage drops below approximately 1.7V, UVLO turns off the MOSFET switch. Under-voltage detection functions only when the switch is enabled. 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 parasitic body diode between drain and source of the MOSFET, the RT9724 prevents reverse current flow if VOUT is externally forced to a higher voltage than VIN when the chip is disabled (VEN < 0.8V). S D S D G G Normal MOSFET RT9724 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 will be turned off, reducing the supply current to 0.1μA typical. Floating the EN 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. 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, satisfying the USB voltage droop requirements. Copyright © 2012 Richtek Technology Corporation. All rights reserved. www.richtek.com 8 Current Limiting and Short-Circuit Protection The current limit circuitry prevents damage to the MOSFET switch and the hub downstream port but can deliver load current up to the current limit threshold of typically 2A. 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 occurs or the fault is removed. Universal Serial Bus (USB) & Power Distribution The goal of USB is to enable device from different vendors to interoperate in an open architecture. USB features include ease of use for the end user, a wide range of workloads and applications, robustness, synergy with the PC industry, and low-cost implementation. Benefits include self-identifying peripherals, dynamically attachable and reconfigurable peripherals, multiple connections (support for concurrent operation of many devices), support for as many as 127 physical devices, and compatibility with PC Plug-and-Play architecture. The Universal Serial Bus connects USB devices with a USB host: each USB system has one USB host. USB devices are classified either as hubs, which provide additional attachment points to the USB, or as functions, which provide capabilities to the system (for example, a digital joystick). Hub devices are then classified as either Bus-Power Hubs or Self-Powered Hubs. A Bus-Powered Hub draws all of the power to any internal functions and downstream ports from the USB connector power pins. The hub may draw up to 500mA from the upstream device. External ports in a Bus-Powered Hub can supply up to 100mA per port, with a maximum of four external ports. is a registered trademark of Richtek Technology Corporation. DS9724-02 July 2012 RT9724 Self-Powered Hub power for the internal functions and downstream ports does not come from the USB, although the USB interface may draw up to 100mA from its upstream connection, to allow the interface to function when the remainder of the hub is powered down. The hub must be able to supply up to 500mA on all of its external downstream ports. Please refer to Universal Serial Specification Revision 2.0 for more details on designing compliant USB hub and host systems. resistance between the bypass capacitor and the downstream connector to reduce EMI and decouple voltage droop caused when downstream cables are hot-insertion transients. Ferrite beads in series with VBUS, the ground line and the 0.1μF bypass capacitors at the power connector pins are recommended for EMI and ESD protection. The bypass capacitor itself should have a low dissipation factor to allow decoupling at higher frequencies. Over current protection devices such as fuses and PTC resistors (also called polyfuse or polyswitch) have slow trip times, high on-resistance, and lack the necessary circuitry for USB-required fault reporting. Voltage Drop The faster trip time of the RT9724 power distribution allows designers to design hubs that can operate through faults. The RT9724 provides low on-resistance and internal faultreporting circuitry to meet voltage regulation and fault notification requirements. Because the devices are also power switches, the designer of self-powered hubs has the flexibility to turn off power to output ports. Unlike a normal MOSFET, the devices have controlled rise and fall times to provide the needed inrush current limiting required for the bus-powered hub power switch. The USB specification states a minimum port-output voltage in two locations on the bus, 4.75V out of a SelfPowered Hub port and 4.4V out of a Bus-Powered Hub port. As with the Self-Powered Hub, all resistive voltage drops for the Bus-Powered Hub must be accounted for to guarantee voltage regulation (see Figure 7-47 of Universal Serial Specification Revision 2.0 ). The following calculation determines VOUT (MIN) for multiple ports (NPORTS) ganged together through one switch (if using one switch per port, NPORTS is equal to 1) : VOUT (MIN) = 4.75V − [ II x ( 4 x RCONN + 2 x RCABLE ) ] − (0.1A x NPORTS x RSWITCH ) − VPCB Where RCONN = Resistance of connector contacts Supply Filter/Bypass Capacitor A 1uF low-ESR ceramic capacitor from VIN to GND, 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. The input transient must not exceed 6V of the absolute maximum supply voltage even for a short duration. Output Filter Capacitor A low-ESR 150uF aluminum electrolytic or tantalum between VOUT and GND is strongly recommended to meet the 330mV maximum droop requirement in the hub VBUS (Per USB 2.0, output ports must have a minimum 120μF of low-ESR bulk capacitance per hub). Standard bypass methods should be used to minimize inductance and Copyright © 2012 Richtek Technology Corporation. All rights reserved. DS9724-02 July 2012 (two contacts per connector) RCABLE = Resistance of upstream cable wires (one 5V and one GND) RSWITCH = Resistance of power switch (90mΩ typical for RT9715) VPCB = PCB voltage drop The USB specification defines the maximum resistance per contact (RCONN) of the USB connector to be 30mΩ and the drop across the PCB and switch to be 100mV. This basically leaves two variables in the equation: the resistance of the switch and the resistance of the cable. If the hub consumes the maximum current (II) of 500mA, the maximum resistance of the cable is 90mΩ. is a registered trademark of Richtek Technology Corporation. www.richtek.com 9 RT9724 The resistance of the switch is defined as follows : Thermal Considerations RSWITCH = { 4.75V − 4.4V − [ 0.5A x ( 4 x 30mΩ + 2 x The maximum power dissipation depends on the thermal resistance of IC package, PCB layout, the rate of surroundings airflow and temperature difference between junction to ambient. The maximum power dissipation can be calculated by following formula : 90mΩ) ] − VPCB } ÷ ( 0.1A x NPORTS ) = (200mV − VPCB ) ÷ ( 0.1A x NPORTS ) If the voltage drop across the PCB is limited to 100mV, the maximum resistance for the switch is 250mΩ for four ports ganged together. The RT9724, with its maximum 100mΩ on-resistance over temperature, can fit the demand of this requirement. Thermal Shutdown Thermal protection limits the power dissipation in the RT9724. When the operation junction temperature exceeds 130°C, the OTP circuit starts the thermal shutdown function and turns the pass element off. The pass element turn on again after the junction temperature cools to 80°C. The RT9724 lowers its OTP trip level from 130°C to 100°C when output short circuit occurs (VOUT < 1V) as shown in Figure 1. VOUT Short to GND 1V For recommended operating conditions specification, the maximum junction temperature is 125°C. The junction to ambient thermal resistance θJA is layout dependent. For SOT-23-5 package, the thermal resistance θ JA is 218.1°C/W on the standard JEDEC 51-7 four layers thermal test board. For WDFN-8L 2x2 package, the thermal resistance θJA is 120°C/W on the standard JEDEC 51-7 four layers thermal test board. The maximum power dissipation at TA = 25°C can be calculated by following formula : PD(MAX) = (125°C − 25°C) / (120°C/W) = 0.833W for WDFN-8L 2x2 package The maximum power dissipation depends on operating ambient temperature for fixed T J(MAX) and thermal resistance θJA. The Figure 2 of derating curves allows the designer to see the effect of rising ambient temperature on the maximum power allowed. IOUT Thermal Shutdown 1.0 100 °C 80 °C Figure 1. Short Circuit Thermal Folded Back Protection when Output Short Circuit Occurs (Patent) Maximum Power Dissipation (W) IC Temperature where TJ(MAX) is the maximum junction temperature, TA is the ambient temperature, and θJA is the junction to ambient thermal resistance. PD(MAX) = (125°C − 25°C) / (218.1°C/W) = 0.458W for SOT-23-5 package VOUT 130 ° C 110 C ° OTP Trip Point PD(MAX) = (TJ(MAX) − TA) / θJA Single Layer PCB 0.9 0.8 WDFN-8L 2x2 0.7 0.6 SOT-23-5 0.5 0.4 0.3 0.2 0.1 0.0 0 25 50 75 100 125 Ambient Temperature (°C) Figure 2. Derating Curve of Maximum Power Dissipation Copyright © 2012 Richtek Technology Corporation. All rights reserved. www.richtek.com 10 is a registered trademark of Richtek Technology Corporation. DS9724-02 July 2012 RT9724 Layout Consideration For best performance of the RT9724.The following guidelines must be followed : ` Input and Output capacitors should be placed close to the IC and connected to ground plane to reduce noise coupling. ` The GND shoule be connected to a strong ground plane for heat sink. ` Keep the main current traces as possible as short and wide. The main current trace should be as possible as short and wide. VIN VIN 5 4 2 CIN 3 EN GND VOUT COUT The input and output capacitor should be placed as close as possible to the IC. Figure 3. PCB Layout Guide for SOT-23-5 Package The input and output capacitor should be placed as close as possible to the IC. 8 GND COUT NC 1 VOUT 2 EN 3 GND 4 9 7 6 5 VIN VIN VIN VIN CIN The main current trace should be as possible as short and wide. Figure 4. PCB Layout for WDFN Package Copyright © 2012 Richtek Technology Corporation. All rights reserved. DS9724-02 July 2012 is a registered trademark of Richtek Technology Corporation. www.richtek.com 11 RT9724 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 Copyright © 2012 Richtek Technology Corporation. All rights reserved. www.richtek.com 12 is a registered trademark of Richtek Technology Corporation. DS9724-02 July 2012 RT9724 D2 D L E E2 1 e SEE DETAIL A 2 b A3 Symbol 1 Note : The configuration of the Pin #1 identifier is optional, but must be located within the zone indicated. Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 0.700 0.800 0.028 0.031 A1 0.000 0.050 0.000 0.002 A3 0.175 0.250 0.007 0.010 b 0.200 0.300 0.008 0.012 D 1.950 2.050 0.077 0.081 D2 1.000 1.250 0.039 0.049 E 1.950 2.050 0.077 0.081 E2 0.400 0.650 0.016 0.026 e L 2 DETAIL A Pin #1 ID and Tie Bar Mark Options A A1 1 0.500 0.300 0.020 0.400 0.012 0.016 W-Type 8L DFN 2x2 Package Richtek Technology Corporation 5F, No. 20, Taiyuen Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Richtek products are sold by description only. Richtek reserves the right to change the circuitry and/or specifications without notice at any time. Customers should obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete. Richtek cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Richtek product. Information furnished by Richtek is believed to be accurate and reliable. However, no responsibility is assumed by Richtek or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Richtek or its subsidiaries. DS9724-02 July 2012 www.richtek.com 13