RT9711BGB

RT9711A/B/C/D 80mΩ Ω, 1.5A/0.6A High-Side Power Switches with Flag General Description Features The RT9711A/B/C/D are cost-effective, low voltage, single N-MOSFET high-side power switches, optimized for selfpowered and bus-powered Universal Serial Bus (USB) applications. The RT9711 series are equipped with a charge pump circuitry to drive the internal MOSFET switch. The switch's low RDS(ON), 80mΩ, meets USB voltage drop z Compliant to USB Specifications z Built-In N-MOSFET Ω (SOT-23-5 & TSOT-23-5) and ` Typical RDS(ON) : 80mΩ 90mΩ Ω (SOP-8 & MSOP-8) Output Can Be Forced Higher Than Input (Off-State) Low Supply Current : 25μ μA Typical at Switch On State 1μ μA Typical at Switch Off State Guaranteed 1.5A for RT9711A/B and 0.6A for RT9711C/D Continuous Load Current Wide Input Voltage Ranges : 2.5V to 5.5V Open-Drain Fault Flag Output Hot Plug-In Application (Soft-Start) 1.7V Typical Under-Voltage Lockout (UVLO) Current Limiting Protection Thermal Shutdown Protection Reverse Current Flow Blocking (no body diode) Smallest SOT-23-5 and TSOT-23-5 Packages Minimizes Board Space UL Approved−E219878 TUV IEC60950-1 : 2005 Certified RoHS Compliant and 100% Lead (Pb)-Free z z requirements. A flag output is available to indicate fault conditions to the local USB controller. Additional features include soft-start to limit inrush current during plug-in, thermal shutdown to prevent catastrophic switch failure from high-current loads, under-voltage lockout (UVLO) to ensure that the device remains off unless there is a valid input voltage present, fault current is limited to typically 2.5A for RT9711A/B in dual ports and 1A for RT9711C/D in single port in accordance with the USB power requirements, lower quiescent current as 25μA making this device ideal for portable battery-operated equipment. The RT9711 series are available in SOT-23-5, TSOT-23-5, SOP-8 and MSOP-8 packages fitting different aspect of broad applications. Ordering Information RT9711 Package Type B : SOT-23-5 BG : SOT-23-5 (G-Type) J5 : TSOT-23-5 S : SOP-8 F : MSOP-8 Lead Plating System P : Pb Free G : Green (Halogen Free and Pb Free) Note : Output Current/EN Function A : 1.5A/Active High B : 1.5A/Active Low C : 0.6A/Active High D : 0.6A/Active Low Richtek products are : ` RoHS compliant and compatible with the current require- ` Suitable for use in SnPb or Pb-free soldering processes. z z z z z z z z z z z z Applications z z z z z z z z USB Bus/Self Powered Hubs USB Peripherals ACPI Power Distribution PC Card Hot Swap Notebook, Motherboard PCs Battery-Powered Equipment Hot-Plug Power Supplies Battery-Charger Circuits Marking Information For marking information, contact our sales representative directly or through a Richtek distributor located in your area. ments of IPC/JEDEC J-STD-020. DS9711A/B/C/D-03 April 2011 www.richtek.com 1 RT9711A/B/C/D Pin Configurations (TOP VIEW) VOUT VIN VIN EN/EN 5 4 5 4 2 GND 3 2 FLG GND EN/EN Over -Current FLG RT9711A/B/C/D GND 10µF + VOUT COUT 3 6 VOUT EN/EN 4 5 FLG SOP-8/MSOP-8 Pin Name Pin Function USB Controller Supply Voltage 5V EN/EN VOUT VIN Functional Pin Description Pull-Up Resistor (10K to 100K) RT9711A/C Chip Enable 7 SOT-23-5 (G-Type) Typical Application Circuit VIN VOUT 2 VOUT GND NC SOT-23-5/TSOT-23-5 CIN 1µF 3 8 VIN VBUS Power Input Voltage VOUT Output Voltage GND Ground EN/EN Chip Enable. Never let this pin floating. (Active High for RT9711A/C, Active Low D+ D- 150µF for RT9711B/D) GND RT9711B/D Chip Enable Ferrite Beads VIN FLG Open-Drain Fault Flag Output Data Note: A low-ESR 150μF aluminum electrolytic or tantalum between VOUT and GND is strongly recommended to meet the 330mV maximum droop requirement in the hub VBUS. (see Application Information Section for further details) Function Block Diagram VIN EN/EN Bias UVLO Oscillator Charge Pump Thermal Protection Current Limiting Gate Control Output Voltage Detection VOUT FLG Delay GND www.richtek.com 2 DS9711A/B/C/D-03 April 2011 RT9711A/B/C/D Absolute Maximum Ratings z z z z z z z z z (Note 1) Supply Voltage --------------------------------------------------------------------------------------------------------- 6.5V Chip Enable Input Voltage ------------------------------------------------------------------------------------------- −0.3V to 6.5V Flag Voltage ------------------------------------------------------------------------------------------------------------ 6.5V Power Dissipation, PD @ TA = 25°C SOT-23-5, TSOT-23-5 ------------------------------------------------------------------------------------------------- 0.4W SOP-8, MSOP-8 ------------------------------------------------------------------------------------------------------- 0.625W Package Thermal Resistance (Note 2) SOT-23-5, TSOT-23-5, θJA ------------------------------------------------------------------------------------------- 250°C/W SOP-8, MSOP-8, θJA ------------------------------------------------------------------------------------------------- 160°C/W Junction Temperature ------------------------------------------------------------------------------------------------- 150°C Lead Temperature (Soldering, 10 sec.) --------------------------------------------------------------------------- 260°C Storage Temperature Range ---------------------------------------------------------------------------------------- −65°C to 150°C ESD Susceptibility (Note 3) HBM (Human Body Mode) ------------------------------------------------------------------------------------------ 2kV MM (Machine Mode) -------------------------------------------------------------------------------------------------- 200V Recommended Operating Conditions z z z z (Note 4) Supply Input Voltage -------------------------------------------------------------------------------------------------- 2.5V to 5.5V Chip Enable Input Voltage ------------------------------------------------------------------------------------------- 0V to 5.5V Junction Temperature Range ---------------------------------------------------------------------------------------- −40°C to 125°C Ambient Temperature Range ---------------------------------------------------------------------------------------- −40°C to 85°C Electrical Characteristics (VIN = 5V, CIN = COUT = 1μF, TA = 25°C, unless otherwise specified) Parameter Switch On Resistance (RT9711A/B) Switch On Resistance (RT9711C/D) Symbol SOT-23-5, TSOT-23-5 SOP-8, MSOP-8 SOT-23-5, TSOT-23-5 Test Conditions I OUT = 1A, VIN = 5V RDS(ON) I OUT = 0.5A, VIN = 5V SOP-8, MSOP-8 Min Typ Max -- 80 100 -- 90 110 -- 80 100 -- 90 110 Units mΩ mΩ ISW_ON switch on, RLOAD Open -- 25 45 ISW_OFF switch off, RLOAD Open -- 0.1 1 Logic-Low Voltage V IL V IN = 2.5V to 5.5V -- -- 0.8 V Logic-High Voltage V IH V IN = 2.5V to 5.5V 2.0 -- -- V EN/EN Input Current IEN/EN V EN/EN = 0V to 5.5V -- 0.01 -- μA Output Leakage Current ILEA K V EN = 0V, V EN = 5V, R LOAD = 0Ω -- 0.5 10 μA Output Turn-On Rise Time TON_RISE 10% to 90% of VO UT rising -- 400 -- us 1.6 2.5 3.2 A 0.7 1 1.4 A Supply Current EN/EN Threshold Current Limit RT9711A/B RT9711C/D ILIM Current Ramp (< 0.1A/ms) on V OUT μA To be continued DS9711A/B/C/D-03 April 2011 www.richtek.com 3 RT9711A/B/C/D Parameter Test Conditions Min Typ Max Units ISC_FB VOUT = 0V, measured prior to thermal shutdown -- 1 -- -- 0.8 -- FLAG Output Resistance RFLG ISINK = 1mA -- 20 400 Ω FLAG Off Current IFLG_OFF VFLG = 5V -- 0.01 1 μA 5 12 20 ms -- 75 150 Ω 1.3 1.7 -- V -- 0.1 -- V Short Circuit Fold-Back Current FLAG Delay Time RT9711A/B Symbol RT9711C/D (Note 5) tD From fault condition to FLG assertion A Shutdown Pull-Low Resistance RDS Under-voltage Lockout VUVLO VE N = 0V, VEN = 5V VIN increasing Under-voltage Hysteresis ΔVUVLO VIN decreasing Thermal Shutdown Protection TSD -- 130 -- °C Thermal Shutdown 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. θJA is measured in the natural convection at TA = 25°C on a low effective thermal conductivity single layer test board of JEDEC 51-3 thermal measurement standard. Note 3. Devices are ESD sensitive. Handling precaution is recommended. Note 4. The device is not guaranteed to function outside its operating conditions. Note 5. The FLAG delay time is input voltage dependent, see“ Typical Operating Characteristics” graph for further details. www.richtek.com 4 DS9711A/B/C/D-03 April 2011 RT9711A/B/C/D Typical Operating Characteristics Switch On Resistance vs. Temperature Switch On Resistance vs. Temperature 0.25 Switch On Resistance (Ω) Switch On Resistance (Ω) 0.25 0.2 0.15 0.1 0.05 SOP-8, VIN = 5V, ILOAD = 1.5A CIN = 1uF/X7R, COUT = 10μF/X7R 0 -40 -20 0 20 40 0.2 0.15 0.1 0.05 0 60 80 100 SOT-23-5, VIN = 5V, ILOAD = 1.5A CIN = 1μF/X7R, COUT = 10μF/X7R -40 120 -20 0 20 Temperature (°C) Supply Current (uA) Switch on Resistance (mΩ) 80 60 2.5 3 3.5 30 25 20 15 10 SOT-23-5, RL = Open CIN = COUT = 33μF/Electrolytic 5 SOT-23-5, ILOAD = 1.5A CIN = COUT = 33μF/Electrolytic 2 0 4 4.5 5 2 5.5 2.5 3 Input Voltage (V) 3.5 4 4.5 5 5.5 Input Voltage (V) Supply Current vs. Temperature Current Limit vs. Input Voltage 30 2 25 1.8 Current Limit (A) Supply Current (uA) 120 35 100 20 15 10 0 100 40 120 5 80 Supply Current vs. Input Voltage Switch on Resistance vs. Input Voltage 20 60 Temperature (°C) 140 40 40 1.6 1.4 1.2 VIN = 5V, Switch On, RLOAD Open CIN = COUT = 33μF/Electrolytic -40 -20 0 20 40 60 Temperature (°C) DS9711A/B/C/D-03 April 2011 1 80 100 120 RT9711A/B, VIN = VEN = 5V CIN = 1μF/X7R, COUT = 10μF/X7R 2 2.5 3 3.5 4 4.5 5 5.5 Input Voltage (V) www.richtek.com 5 RT9711A/B/C/D EN PinThreshold Voltage vs. Input Voltage Current Limit vs. Temperature 2 EN Threshold Voltage (V) 2 Current Limit (A) 1.8 1.6 1.4 1.2 RT9711A/B, VIN = 5V CIN = 1μF/X7R, COUT = 10μF/X7R 1 -40 -20 0 20 40 60 1.6 1.2 0.8 0.4 0 80 100 RT9711B, ILOAD = 100mA CIN = COUT = 33μF/Electrolytic 2 120 2.5 3 Turn-Off Leakage Current (uA) EN Pin Threshold Voltage (V) 4 2 1.6 1.2 0.8 RT9711B, VIN = 5V, ILOAD = 100mA CIN = COUT = 33μF/Electrolytic -40 -20 0 20 40 60 3.5 5 5.5 VIN = 5V, RLOAD = 0Ω CIN = 33μF/Electrolytic COUT = 1μF/X7R 3 2.5 2 1.5 1 0.5 0 80 100 -40 120 -20 0 Temperature (°C) 20 40 60 80 100 120 Temperature (°C) Turn-Off Falling Time vs. Temperature Turn-On Rising Time vs. Temperature 100 700 600 Turn-Off Falling Time (us) Turn-On Rising Time (us) 4.5 Turn-Off Leakage Current vs. Temperature EN Pin Threshold Voltage vs. Temperature 2.4 0 4 Input Voltage (V) Temperature (°C) 0.4 3.5 500 400 300 200 100 0 VIN = 5V, RLOAD = 30Ω CIN = 33μF/Electrolytic COUT = 1μF/Electrolytic -40 -20 0 20 60 40 20 0 40 60 Temperature (°C) www.richtek.com 6 80 80 100 120 VIN = 5V, RLOAD = 30Ω CIN = 33μF/Electrolytic COUT = 1μF/Electrolytic -40 -20 0 20 40 60 80 100 120 Temperature (°C) DS9711A/B/C/D-03 April 2011 RT9711A/B/C/D Swith Off Supply Current vs. Temperature UVLO Threshold vs. Temperature 2.4 0.8 2 0.6 UVLO Threshold (V) Swith Off Supply Current (uA) 1 0.4 0.2 0 -0.2 -0.4 -0.6 -1 -40 -20 0 20 40 1.2 0.8 0.4 VIN = 5V, RLOAD = Open CIN = COUT = 33μF/Electrolytic -0.8 1.6 0 60 80 100 VIN Increasing, ILOAD = 15mA CIN = COUT = 33μF/Electrolytic -40 120 -20 0 20 40 60 80 100 120 Temperature (°C) Temperature (°C) Flag Delay Time vs. Temperature FLAG Delay Time vs. Input Voltage 16 20 Flag Delay Time (ms) FLAG Delay Time (ms) 15 16 12 8 4 14 13 12 11 10 RLOAD = 1Ω CIN = COUT = 33μF/Electrolytic 0 2 2.5 3 3.5 4 9 8 7 4.5 5 RLOAD = 1Ω, VIN = 5V CIN = COUT = 33μF/Electrolytic -40 5.5 -20 0 20 40 60 80 100 Input Voltage(V) Temperature (°C) Flag Response with Ramped Load Load Transient Response 120 4.8V VLAG (5V/Div) VOUT (5V/Div) VOUT (1V/Div) IOUT (1A/Div) SOT-23-5, VIN = 5V CIN = COUT = 33μF/Electrolytic Time (2.5ms/Div) DS9711A/B/C/D-03 April 2011 IOUT (1A/Div) 1.5A VIN = 5V, COUT = 1μF CIN = 33μF/Electrolytic RLOAD = 1kΩ to 2.2Ω Time (1ms/Div) www.richtek.com 7 RT9711A/B/C/D Turn On Response VEN (5V/Div) Turn Off Response VEN (5V/Div) VOUT (5V/Div) RT9711B, VIN = 5V RLOAD = 30Ω CIN = 33μF/Electrolytic COUT = 1μF/Electrolytic VOUT (5V/Div) RT9711B, VIN = 5V, RLOAD = 30Ω CIN = 33μF/Electrolytic COUT = 1μF/Electrolytic Time (100μs/Div) Time (100μs/Div) UVLO at Rising UVLO at Falling VIN = 5V, RLOAD = 30Ω COUT = 1μF CIN = 33μF/Electrolytic VIN (1V/Div) VIN (1V/Div) SOT-23-5, VIN = 5V, RLOAD = 30Ω, COUT = 1μF CIN = 33μF/Electrolytic VOUT (1V/Div) VOUT (1V/Div) Time (2.5ms/Div) Time (5ms/Div) Flag Response during Short Circuit Flag Response during Over Load VIN = 5V, RLOAD = 0Ω CIN = COUT = 33μF/Electrolytic VIN = 5V, RLOAD = 2Ω CIN = COUT = 33μF/Electrolytic VEN (5V/Div) VOUT (5V/Div) VFLG (5V/Div) VFLG (5V/Div) IOUT (1A/Div) IOUT (1A/Div) Time (5ms/Div) www.richtek.com 8 Time (5ms/Div) DS9711A/B/C/D-03 April 2011 RT9711A/B/C/D Output Voltage vs. Output Current Output Voltage vs. Output Current 5.0 5.0 4.6 TA = 25°C 4.2 3.8 3.4 TA = -45°C 3.0 TA = 85°C 2.6 2.2 1.8 1.4 1.0 0.6 TA = 85°C 4.2 Output Voltage (V) Output Voltage (V) 4.6 3.8 3.4 TA = -45°C 3.0 2.6 TA = 25°C 2.2 1.8 1.4 1.0 RT9711A, VIN = 5V 0 0.2 0.4 0.6 0.6 0.8 1 1.2 1.4 1.6 1.8 RT9711C, VIN = 5V 0 2 0.2 Output Current (A) 2.1 1.6 Current Limit Threshold (A) Current Limit Threshold (A) 1.7 TA = -45°C TA = 25°C 1.8 1.7 TA = 85°C 1.6 1.5 RT9711A, VIN = 5V 2.5 3 3.5 DS9711A/B/C/D-03 April 2011 1.5 1.4 1.3 4 4.5 1 1.2 1.4 1.6 5 5.5 TA = 25°C TA = -45°C TA = 85°C 1.2 1.1 1 Input Voltage (V) 0.8 Current Limit Threshold vs. Input Voltage Current Limit Threshold vs. Input Voltage 1.9 0.6 Output Current (A) 2.2 2.0 0.4 RT9711C, VIN = 5V 2.5 3 3.5 4 4.5 5 5.5 Input Voltage (V) www.richtek.com 9 RT9711A/B/C/D Applications Information The RT9711A/B/C/D are single N-MOSFET high-side power switches with enable input, optimized for selfpowered and bus-powered Universal Serial Bus (USB) applications. The RT9711 series are equipped with a charge pump circuitry to drive the internal N-MOSFET switch; the switch's low RDS(ON), 80mΩ, meets USB voltage drop requirements; and a flag output is available to indicate fault conditions to the local USB controller. 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 a parasitic body diode between drain and source of the MOSFET, the RT9711A/B/C/D prevents reverse current flow if VOUT being externally forced to a higher voltage than VIN when the output disabled (VEN < 0.8V or VEN > 2V). D S S D 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. Fault Flag The RT9711 series provides a FLG signal pin which is an N-Channel open drain MOSFET output. This open drain output goes low when VOUT < VIN − 1V, current limit or the die temperature exceeds 130°C approximately. The FLG output is capable of sinking a 10mA load to typically 200mV above ground. The FLG pin requires a pull-up resistor, this resistor should be large in value to reduce energy drain. A 100kΩ pull-up resistor works well for most applications. In the case of an over-current condition, FLG will be asserted only after the flag response delay time, tD, has elapsed. This ensures that FLG is asserted only upon valid over-current conditions and that erroneous error reporting is eliminated. For example, false over-current conditions may occur during hot-plug events when extremely large capacitive loads are connected and causes a high transient inrush current that exceeds the current limit threshold. The FLG response delay time tD is typically 10ms. Under-Voltage Lockout G G Normal MOSFET RT9711A/B/C/D Chip Enable Input The switch will be disabled when the EN/EN pin is in a logic low/high condition. During this condition, the internal circuitry and MOSFET are turned off, reducing the supply current to 0.1μA typical. Floating the EN/EN may cause unpredictable operation. EN should not be allowed to go negative with respect to GND. The EN/EN pin may be directly tied to VIN (GND) to keep the part on. www.richtek.com 10 Under-voltage lockout (UVLO) prevents the MOSFET switch from turning on until input voltage exceeds approximately 1.7V. If input voltage drops below approximately 1.3V, UVLO turns off the MOSFET switch, FLG will be asserted accordingly. Under-voltage detection functions only when the switch is enabled. 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 2.5A through the switch of RT9711A/B and 1A for RT9711C/D respectively. 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 DS9711A/B/C/D-03 April 2011 RT9711A/B/C/D Thermal Shutdown Thermal shutdown is employed to protect the device from damage if the die temperature exceeds approxi- mately 130°C. If enabled, the switch automatically restarts when the die temperature falls 20°C. The output and FLG signal will continue to cycle on and off until the device is disabled or the fault is removed. Power Dissipation The junction temperature of the RT9711 series depend on several factors such as the load, PCB layout, ambient temperature and package type. The output pin of RT9711A/B/C/D can deliver the current of up to 1.5A (RT9711A/B), and 0.6A (RT9711C/D) respectively over the full operating junction temperature range. However, the maximum output current must be derated at higher ambient temperature to ensure the junction temperature does not exceed 100°C. With all possible conditions, the junction temperature must be within the range specified under operating conditions. Power dissipation can be calculated based on the output current and the RDS(ON) of switch as below. PD = RDS(ON) x IOUT2 Although the devices are rated for 1.5A and 0.6A of output current, but the application may limit the amount of output current based on the total power dissipation and the ambient temperature. The final operating junction temperature for any set of conditions can be estimated by the following thermal equation : PD (MAX) = (TJ (MAX) - TA) / θJA Where T J(MAX) is the maximum operation junction temperature 125°C, TA is the ambient temperature and the θJA is the junction to ambient thermal resistance. The junction to ambient thermal resistance θJA is layout dependent. For SOT-23-5 and TSOT-23-5 packages, the thermal resistance θJA is 250°C/W on the standard JEDEC 51-3 single-layer thermal test board. DS9711A/B/C/D-03 April 2011 And for SOP-8 and MSOP-8 packages, the thermal resistance θ JA is 160°C/W. The maximum power dissipation at TA = 25°C can be calculated by following formula : P D(MAX) = (125°C − 25°C) / 250°C/W = 0.4W for SOT-23-5 and TSOT-23-5 packages PD(MAX) = (125°C − 25°C) / 160°C/W = 0.625W for SOP-8 and MSOP-8 packages The maximum power dissipation depends on operating ambient temperature for fixed T J(MAX) and thermal resistance θJA. For RT9711A/B/C/D packages, the Figure 1 of derating curves allows the designer to see the effect of rising ambient temperature on the maximum power allowed. 0.7 Maximum Power Dissipation (W) limit threshold is exceeded the device enters constant current mode until the thermal shutdown occurs or the fault is removed. Single Layer PCB 0.6 SOP-8, MSOP-8 0.5 0.4 0.3 SOT-23-5, TSOT-23-5 0.2 0.1 0 0 25 50 75 100 125 Ambient Temperature (°C) Figure 1. Derating Curves for RT9711A/B/C/D Package Universal Serial Bus (USB) & Power Distribution The goal of USB is to be enabled 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 implement- ation. 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 www.richtek.com 11 RT9711A/B/C/D 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. 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 connect, 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. 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. The faster trip time of the RT9711A/B/C/D power distribution allow designers to design hubs that can operate through faults. The RT9711A/B/C/D have low on-resistance and internal fault-reporting circuitry that help the designer 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. Supply Filter/Bypass Capacitor A 1μF 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 www.richtek.com 12 (from source lead inductance) to destroy the internal control circuitry. The input transient must not exceed 6.5V of the absolute maximum supply voltage even for a short duration. Output Filter Capacitor A low-ESR 150μF 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 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. Voltage Drop The USB specification states a minimum port-output voltage in two locations on the bus, 4.75V out of a SelfPowered Hub port and 4.40V 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 (two contacts per connector) RCABLE = Resistance of upstream cable wires (one 5V and one GND) RSWITCH = Resistance of power switch (80mΩ typical for RT9711A/B/C/D) DS9711A/B/C/D-03 April 2011 RT9711A/B/C/D 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. The resistance of the switch is defined as follows : RSWITCH = { 4.75V − 4.4V − [ 0.5A x ( 4 x 30mΩ + 2 x 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 RT9711A/B/C/D, with its maximum 100mΩ on-resistance over temperature, easily meets this requirement. Layout Considerations For best performance of the RT9711 series, the following guidelines muse be strictly followed : ` Input and output capacitors should be placed close to the IC and connected to ground plane to reduce noise coupling. ` The GND should be connected to a strong ground plane for heat sink. ` Keep the main current traces as possible as short and wide. The input and output capacitors should be placed as close as possible to the IC. V IN V OUT GND V IN FLG GND EN Figure 2. PCB Layout Guide DS9711A/B/C/D-03 April 2011 www.richtek.com 13 RT9711A/B/C/D 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 www.richtek.com 14 DS9711A/B/C/D-03 April 2011 RT9711A/B/C/D H D L B C b A A1 e Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 0.700 1.000 0.028 0.039 A1 0.000 0.100 0.000 0.004 B 1.397 1.803 0.055 0.071 b 0.300 0.559 0.012 0.022 C 2.591 3.000 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 TSOT-23-5 Surface Mount Package DS9711A/B/C/D-03 April 2011 www.richtek.com 15 RT9711A/B/C/D H A M J B F C I D Dimensions In Millimeters Dimensions In Inches Symbol Min Max Min Max A 4.801 5.004 0.189 0.197 B 3.810 3.988 0.150 0.157 C 1.346 1.753 0.053 0.069 D 0.330 0.508 0.013 0.020 F 1.194 1.346 0.047 0.053 H 0.170 0.254 0.007 0.010 I 0.050 0.254 0.002 0.010 J 5.791 6.200 0.228 0.244 M 0.400 1.270 0.016 0.050 8-Lead SOP Plastic Package www.richtek.com 16 DS9711A/B/C/D-03 April 2011 RT9711A/B/C/D D L E1 E e A2 A A1 b Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 0.810 1.100 0.032 0.043 A1 0.000 0.150 0.000 0.006 A2 0.750 0.950 0.030 0.037 b 0.220 0.380 0.009 0.015 D 2.900 3.100 0.114 0.122 e 0.650 0.026 E 4.800 5.000 0.189 0.197 E1 2.900 3.100 0.114 0.122 L 0.400 0.800 0.016 0.031 8-Lead MSOP Plastic 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: marketing@richtek.com 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. DS9711A/B/C/D-03 April 2011 www.richtek.com 17