RT9722 145mΩ Ω, 1.5A Power Switch with Programmable Current Limit General Description Features The RT9722 is a cost effective, low voltage, single P-MOSFET high side power switch IC. Typical 145mΩ switch on resistance and 10μA quiescent current are realized in this IC. In order to fit different application, a SET pin is offered for current limit point setting, a resistor from SET to Ground sets the current limit for this switch. z In addition, the RT9722 integrates a thermal shutdown circuit and under voltage lockout circuit for overall protection, and a FLAG output with delay is available to indicate fault conditions to the local controller. The RT9722 is an ideal solution for high side power load switch and can support flexible applications since it is available in various package such as WDFN-6L 2x2, SOT-23-5 and SOT-23-6. Ordering Information RT9722 z z z z z z z Programmable Current Limit : 0.2A to 1.5A Low Quiescent Current : 10μ μA Low Shutdown Current : 0.1μ μA 145mΩ Ω Switch On Resistance Operating Voltage Range : 2.4V to 5.5V Under Voltage Lockout Thermal Shutdown Protection RoHS Compliant and Halogen Free Applications z z z z z Handheld Devices Hot Swap Supplies Notebooks Peripheral Ports Personal Communication Devices Pin Configurations Package Type B : SOT-23-5 E : SOT-23-6 QW : WDFN-6L 2x2 (W-Type) (TOP VIEW) VIN EN/EN 5 4 Lead Plating System G : Green (Halogen Free and Pb Free) EN Function A : Active High B : Active Low Note : 2 VOUT GND SET SOT-23-5 VIN FLG EN/EN Richtek products are : ` 6 5 4 2 3 RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. ` 3 Suitable for use in SnPb or Pb-free soldering processes. VOUT GND SET SET 1 VIN VOUT 2 GND SOT-23-6 3 7 5 EN/EN NC 4 FLG 6 WDFN-6L 2x2 DS9722-00 August 2011 www.richtek.com 1 RT9722 Marking Information RT9722BGB RT9722AGB 1H= : Product Code 1H=DNN 1S= : Product Code 1S=DNN DNN : Date Code DNN : Date Code RT9722BGE RT9722AGE DQ= : Product Code DQ=DNN DT= : Product Code DT=DNN DNN : Date Code RT9722BGQW RT9722AGQW H0 : Product Code H1 : Product Code W : Date Code H0W DNN : Date Code W : Date Code H1W Typical Application Circuit Pull-Up Resistor (10k to 100k) Supply Voltage 5 VIN CIN 1µF Enable SET 3 RT9722 4 EN/EN RSET VIN CIN 1µF Fault Flag FLG RT9722 SET RSET VOUT 1 GND 2 0.47µF Peripheral Figure 1. Typical Application Circuit for SOT-23-5 Package www.richtek.com 2 Supply Voltage Enable EN/EN VOUT GND 0.47µF Peripheral Figure 2. Typical Application Circuit for SOT-23-6 and WDFN-6L 2x2 Package DS9722-00 August 2011 RT9722 Functional Pin Description Pin No. Pin Name Pin Function SOT-23-5 SOT-23-6 WDFN-6L 2x2 1 1 3 2 2 3 3 1 SET Current Limit Set Input. A resistor from SET to GND sets the current limit of the switch. 4 4 6 EN/EN Chip Enable (Active High for RT9722A / Active Low for RT9722B). -- 5 4 FLG Fault Flag Open-Drain Output. 5 6 2 VIN Power Input Voltage. -- -- 5 NC No Internal Connection. VOUT 7 (Exposed Pad) GND Switch Output Voltage. Ground. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. Function Block Diagram SET VIN Current Limiting UVLO EN/EN Bias Thermal Protection Gate Control Output Voltage Detection VOUT FLG Flag Control GND DS9722-00 August 2011 www.richtek.com 3 RT9722 Absolute Maximum Ratings z z z z z z z z z (Note 1) Supply Input Voltage, VIN ------------------------------------------------------------------------------------------------ 6V EN Voltage ------------------------------------------------------------------------------------------------------------------ −0.3V to 6V FLAG, SET Voltage ------------------------------------------------------------------------------------------------------- 6V Power Dissipation, PD @ TA = 25°C SOT-23-5/SOT-23-6 ------------------------------------------------------------------------------------------------------WDFN-6L 2x2 -------------------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2) SOT-23-5/SOT-23-6 ------------------------------------------------------------------------------------------------------WDFN-6L 2x2, θJA --------------------------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------Junction Temperature ----------------------------------------------------------------------------------------------------Storage Temperature Range -------------------------------------------------------------------------------------------ESD Susceptibility (Note 3) HBM -------------------------------------------------------------------------------------------------------------------------MM ---------------------------------------------------------------------------------------------------------------------------- Recommended Operating Conditions z z z z 0.4W 0.606W 250°C/W 165°C/W 260°C 150°C −65°C to 150°C 2kV 200V (Note 4) Supply Input Voltage, VIN -----------------------------------------------------------------------------------------------EN Voltage -----------------------------------------------------------------------------------------------------------------Junction Temperature Range -------------------------------------------------------------------------------------------Ambient Temperature Range -------------------------------------------------------------------------------------------- 2.4V to 5.5V 0V to 5.5V −40°C to 125°C −40°C to 85°C Electrical Characteristics (VIN = 5V, CIN = 1μF, COUT = 0.47μF, TA = 25°C, unless otherwise specified) Parameter Symbol Test Conditions VIN = 5V, RSET = 20kΩ, IOUT = 100mA EN = Active, SET Pin Open, IOUT = 0 EN = Inactive, VOUT = Open Min Typ Max Unit -- 145 180 mΩ -- 10 25 μA -- 0.1 1 μA Switch On Resistance R DS(ON) Quiescent Current IQ Shutdown Current I SHDN EN/EN Threshold Logic-Low Voltage Logic-High VIL -- -- 0.6 VIH 1.4 -- -- EN/EN Input Current I EN/EN VEN/EN = 5V -- 0.01 0.1 μA Output Leakage Current I LEAKAGE Switch Off, VOUT = 0V -- 0.01 1 μA Turn On Time t ON VIN = 5V, RLOAD = 10Ω -- 12 200 μs Turn Off Time t OFF VIN = 5V, RLOAD = 10Ω -- 10 -- μs Current Limit I LIM RSET = 6.8kΩ, VOUT = 4V 0.75 1 1.25 A Minimum Current Limit I LIM(MIN) -- 0.2 -- A Current Limit Response Time t Response -- 10 -- μs RLOAD = 0Ω V To be continued www.richtek.com 4 DS9722-00 August 2011 RT9722 Parameter Symbol Test Conditions Min Typ Max Unit FLG Output Resistance RFLG ISINK = 1mA -- 20 -- Ω FLG Off Current IFLG_Off VFLG = 5V -- 0.01 1 μA FLG Delay Time tD From Fault Condition to FLG Assertion 5 12 20 ms Under Voltage Lockout Threshold VUVLO VIN Increasing -- 2 2.4 V Under Voltage Hysteresis ΔVUVLO VIN Increasing -- 0.1 -- V Thermal Shutdown Protection TSD -- 150 -- °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. DS9722-00 August 2011 www.richtek.com 5 RT9722 Typical Operating Characteristics Supply Current vs. Temperature Supply Current vs. Input Voltage 20 RSET = Open, RLOAD = Open 18 VIN = 5V, RSET = Open, RLOAD = Open 18 16 16 Supply Current (μA) Supply Current (μA) 20 14 12 10 8 6 4 2 14 12 10 8 6 4 2 0 0 2.5 3 3.5 4 4.5 5 5.5 -50 -25 0 Input Voltage (V) VIN = 5V, EN = 0V, RSET = 6.8kΩ, RLOAD = Open 100 125 VIN = 5V, RSET = 16kΩ 500 0.8 Output Current (mA) Shutdown Current (μA)1 75 Output Current vs. Output Voltage 600 0.6 0.4 0.2 400 300 200 100 0 0 -50 -25 0 25 50 75 100 125 0 1 Temperature (°C) 2 3 4 5 Output Voltage (V) RDS(ON) vs. Input Voltage 250 RDS(ON) vs. Temperature 300 RSET = 16kΩ, ILOAD = 100mA RSET = 16kΩ, ILOAD = 100mA 250 RDS(ON) (mΩ) 200 RDS(ON) (mΩ) 50 Temperature (°C) Shutdown Current vs. Temperature 1 25 150 100 50 VIN = 3V 200 150 VIN = 5V 100 50 0 0 2.5 3 3.5 4 4.5 Input Voltage (V) www.richtek.com 6 5 5.5 -50 -25 0 25 50 75 100 125 Temperature (°C) DS9722-00 August 2011 RT9722 UVLO Threshold Voltage vs. Temperature EN Threshold Voltage vs. Input Voltage 1.4 2.6 Rising 1.8 1.6 1.4 EN Threshold Voltage (V) UVLO Threshold Voltage (V) 2.4 2.2 2.0 Falling 1.2 1.0 0.8 0.6 0.4 0.2 VIN = 5V, RSET = 16kΩ, RLOAD = 510Ω 0.0 -50 -25 0 25 50 75 100 1.2 V IH 1.0 VIL 0.8 0.6 0.4 0.2 RSET = 16kΩ, RLOAD = 510Ω 0.0 2.5 125 3 3.5 Current Limit vs. RSET 5.5 Flag Delay Time vs. Input Voltage VIN = 5V, RLOAD = 1Ω 12 1200 Flag Delay Time (ms) Current Limit (mA) 5 14 1400 1000 800 600 400 10 8 6 4 200 2 0 0 0 10 20 30 40 50 60 70 VIN = 5V, RSET = 6.8kΩ, RLOAD = 0Ω, COUT = 0.47μF 2.5 3 3.5 4 4.5 5 5.5 Input Voltage (V) RSET (kΩ) Turn-Off Time vs. Temperature Turn-On Time vs. Temperature 12 30 25 10 VIN = 3V Turn-Off Time (μs) Turn-On Time (μs) 4.5 Input Voltage (V) Temperature (°C) 1600 4 20 VIN = 5V 15 10 VIN = 5V 8 6 VIN = 3V 4 2 5 RSET = 6.8kΩ, RLOAD = 10Ω, COUT = 0.47μF 0 -50 -25 0 25 50 Temperature (°C) DS9722-00 August 2011 75 100 125 RSET = 6.8kΩ, RLOAD = 10Ω, COUT = 0.47μF 0 -50 -25 0 25 50 75 100 125 Temperature (°C) www.richtek.com 7 RT9722 Power Off from EN Power On from EN VEN (5V/Div) VEN (5V/Div) VOUT (2V/Div) VOUT (2V/Div) IOUT (200mA/Div) IOUT (200mA/Div) VIN = 5V, RSET = 6.8kΩ, RLOAD = 10Ω, COUT = 0.47μF VIN = 5V, RSET = 6.8kΩ, RLOAD = 10Ω, COUT = 0.47μF Time (25μs/Div) Time (10μs/Div) Current Limit with Thermal Shutdown VIN (5V/Div) VOUT (1V/Div) VIN (5V/Div) VOUT (5V/Div) Flag (5V/Div) Flag (5V/Div) IOUT (500mA/Div) Short Circuit Protection IOUT (500mA/Div) VIN = 5V, RSET = 16kΩ, RLOAD = 1Ω, COUT = 0.47μF VIN = 5V, RSET = 6.8kΩ, RLOAD = 0Ω, COUT = 0.47μF Time (250ms/Div) Time (25ms/Div) www.richtek.com 8 DS9722-00 August 2011 RT9722 Application Information The RT9722 is a high-side power switch with programmable current limit function. The RT9722 provides active-high (RT9722A) and active-low (RT9722B) enable input and full protection functions make it optimized to replace complex discrete on/off control circuitry. Table 1. Current Limit vs. RSET Resistance Design Current Limit (mA) RSET (kΩ) Min Typ Max 4.7 1125.0 1500 1875.0 5.49 937.5 1250 1562.5 Current Limit Setting 6.8 750.0 1000 1250.0 The current limit value ILIM, can be set by an external resistor between SET and GND. Figure 3 shows the typical current limit value under various setting resistance, RSET. 7.32 675.0 900 1125.0 8.66 600.0 800 1000.0 10.5 525.0 700 875.0 13 450.0 600 750.0 16 375.0 500 625.0 18 337.5 450 562.5 Current Limit vs. RSET 1600 Current Limit (mA) 1400 1200 20 300.0 400 500.0 1000 22.6 262.5 350 437.5 800 30 225.0 300 375.0 600 34.8 187.5 250 312.5 400 47 150.0 200 250.0 200 Chip Enable Input 0 A few standard resistor values of the RSET and its typical current limit set point with ±25% tolerance are listed in Table 1. 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 typically. The maximum guaranteed voltage for a logic low at the EN pin is 0.6V. A minimum guaranteed voltage of 1.4V at the EN pin will turn on the RT9722 again. Floating the input may cause unpredictable operation. EN should not be allowed to go negative with respect to GND. The EN pin can be directly tied to VIN to keep the part on. Input and Output Soft-Start for Hot Plug-In Applications VIN (input) is the power source connected to the internal circuitry and the source of the MOSFET. VOUT (output) is the drain 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. The RT9722 is designed to control current flowing from VIN to VOUT. If a voltage applied to VOUT is greater than the voltage on VIN, large currents may flow and cause damage to the device. 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. 0 10 20 30 40 50 60 70 (kΩ) RSET (kΩ) Figure 3. Current Limit vs. RSET Resistance The accuracy of current limit set point may vary with operating temperature and supply voltage, see “Typical Operating Characteristics” graph for further details. DS9722-00 August 2011 Fault Flag The RT9722 provides a FLG signal pin which is an N-Channel open drain MOSFET output. This open drain output goes low when current limit VOUT < VIN − 1V, or the die temperature exceeds 150°C approximately. The FLG www.richtek.com 9 RT9722 pin requires a pull-up resistor, this resistor should be large in value to reduce energy drain. A 100k pull-up resistor works well for most applications. In the case of an overcurrent 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 a highly large capacitive load is connected and causes a high transient inrush current that exceeds the current limit threshold. The FLG response delay time tD is typically 12ms at VIN = 5V. Under-Voltage Lockout Under-voltage lockout (UVLO) prevents the MOSFET switch from turning on until input voltage exceeds approximately 2V. Under-voltage detection functions only when the chip enable input is enabled. Thermal Shutdown Thermal shutdown is employed to protect the device from damage if the die temperature exceeds approximately 150°C. If enabled, the switch automatically restarts when the die temperature falls 20°C (typ.). The output will continue to cycle on and off until the device is disabled or the fault is removed. Short Circuit Protection The current limit circuitry prevents damage to the MOSFET switch and external load. 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 occurred or the fault is removed. Supply Filter/Bypass Capacitor A 1μF low-ESR ceramic capacitor from VIN to GND (the amount of the capacitance may be increased without limit), 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 www.richtek.com 10 control circuitry. An important note to be award of is the parasitic inductance of PCB traces can cause over-voltage transients if the PCB trace has even a few tens of nH of inductance. The input transient must not exceed 6.0V of the absolute maximum supply voltage even for a short duration. Power Dissipation The device's junction temperature depends on several factors such as the load, PCB layout, ambient temperature and package type. The maximum output current must be derated at higher ambient temperature to ensure the junction temperature does not exceed operating junction temperature 125°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 The application may limit the amount of output current based on the total power dissipation and the ambient temperature. Thermal Considerations 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 : PD(MAX) = (TJ(MAX) − TA) / θJA Where T J(MAX) is the maximum operation junction temperature, TA is the ambient temperature and the θJA is the junction to ambient thermal resistance. For recommended operating conditions specification of RT9722, the maximum operating junction temperature is 125°C. The junction to ambient thermal resistance θJA for SOT-23-5/SOT-23-6 package is 250°C/W and WDFN-6L 2x2 package is 165°C/W on the standard JEDEC 51-3 single-layer thermal test board. 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/SOT-23-6 package DS9722-00 August 2011 RT9722 PD(MAX) = (125°C − 25°C) / (165°C/W) = 0.606W for WDFN-6L 2x2 package The maximum power dissipation depends on operating ambient temperature for fixed T J(MAX) and thermal resistance θJA. For the RT9722 Figure 4 shows the maximum power dissipation allowed under various ambient temperatures. 0.70 Power Dissipation (W) For the best performance of the RT9722, careful PCB layout is necessary. The following guidelines must be considered: ` Keep all input and output traces as short and wide as possible. ` Locate the bypass capacitors as close as possible to the input and output pin of the RT9722. ` Avoid vias as much as possible. If vias are necessary, make them as large as feasible. ` Place a ground plane under all circuitry to lower both resistance and inductance and improve DC and transient performance (Use a separate ground and power plane if possible). Single Layer PCB 0.60 WDFN-6L 2x2 0.50 0.40 0.30 Layout Consideration SOT-23-5/SOT-23-6 0.20 CIN R pull-up 0.10 0.00 0 25 50 75 100 125 Ambient Temperature (°C) Figure 4. RT9722 Maximum Power Dissipation Derating Curve The main current trace should be as possible as short and wide. VIN FLG EN/EN 6 5 4 2 3 VOUT GND SET The input and output capacitors should be placed as close as possible to the IC. COUT RSET Figure 5. PCB Layout Guide DS9722-00 August 2011 www.richtek.com 11 RT9722 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 12 DS9722-00 August 2011 RT9722 H D L C B b A A1 e Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 0.889 1.295 0.031 0.051 A1 0.000 0.152 0.000 0.006 B 1.397 1.803 0.055 0.071 b 0.250 0.560 0.010 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-23-6 Surface Mount Package DS9722-00 August 2011 www.richtek.com 13 RT9722 D2 D L E E2 1 2 e 1 2 1 b A A1 SEE DETAIL A DETAIL A Pin #1 ID and Tie Bar Mark Options A3 Note : The configuration of the Pin #1 identifier is optional, but must be located within the zone indicated. Symbol 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 0.350 0.008 0.014 D 1.950 2.050 0.077 0.081 D2 1.000 1.450 0.039 0.057 E 1.950 2.050 0.077 0.081 E2 0.500 0.850 0.020 0.033 e L 0.650 0.300 0.026 0.400 0.012 0.016 W-Type 6L DFN 2x2 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. www.richtek.com 14 DS9722-00 August 2011