RT2528GSP

® RT2528 120mΩ Ω, 2.5A Power Switch with Adjustable Current Limit General Description Features The RT2528 is a cost effective, low voltage, P-MOSFET power switch IC with an adjustable current limit feature. Low on-resistance (74mΩ typ.) and low supply current (120μA typ.) are designed in this IC.     The RT2528 can offer an adjustable current limit threshold between 0.5A and 2.5A (typ.) via an external resistor. The ±10% current limit accuracy can be realized for all current limit settings.     The RT2528 is an ideal solution for power supply applications since it is functional for various current limit requirements. The RT2528 is available in the thermal enhanced SOP-8 (Exposed Pad) package.  Adjustable Current Limit : 0.5A to 2.5A (typ.) ±10% Current Limit Accuracy @ 2A Over Temperature 120mΩ Ω P-MOSFET Low Supply Current : 120μ μA Input Operating Voltage Range : 2.5V to 5.5V Reverse Input-Output Voltage Protection Built-in Soft-Start AEC-Q100 Grade 3 Certification RoHS Compliant and Halogen Free Applications  Ordering Information  RT2528  Package Type SP : SOP-8 (Exposed Pad-option 2)  Lead Plating System G : Green (Halogen Free and Pb Free) Automotive Audio, Navigation & Info Systems Industrial Grade General Purpose Point of Load Digital Set Top Boxes Vehicle Electronics Pin Configurations (TOP VIEW) Note : Richtek products are :  VOUT RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.  Suitable for use in SnPb or Pb-free soldering processes. 8 VOUT 2 ILIM 3 FAULT 4 GND 9 VIN 7 VIN 6 GND 5 EN SOP-8 (Exposed Pad) Marking Information RT2528GSP : Product Number RT2528 GSPYMDNN YMDNN : Date Code Simplified Application Circuit VIN VIN CIN VOUT COUT RT2528 VOUT RILIM ILIM Enable EN Copyright © 2013 Richtek Technology Corporation. All rights reserved. DS2528-03 November 2013 GND is a registered trademark of Richtek Technology Corporation. www.richtek.com 1 RT2528 Functional Pin Description Pin No. 1, 2 Pin Name VOUT 3 ILIM 4 FAULT 5 EN 6, GND 9 (Exposed Pad) 7, 8 VIN Pin Function Output. Current Limit Setting. Connect an external resistor to set current limit threshold. The recommended resistance range is 10k  RILIM  49.9k. Active-Low Open-Drain Output. Asserted during over-current, over-temperature, or reverse-voltage conditions. Enable Control Input. Logic high turns on the power switch. Ground. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. Power Input. Connect a 10F or greater ceramic capacitor from the VIN to GND as close to the IC as possible. Function Block Diagram Reverse Voltage Comparator + Switch well - Current Sense VIN VOUT 4ms Deglitch EN Drive Current Limit FAULT UVLO Thermal Sense 7.5ms Deglitch GND ILIM Operation The RT2528 is a current-limited power switch using P-MOSFETs for applications where short-circuit or heavy capacitive loads will be encountered. These devices allow users to adjust the current limit threshold between 500mA and 2.5A (typ.) via an external resistor. Additional device shutdown features include over-temperature protection and reverse-voltage protection. Copyright © 2013 Richtek Technology Corporation. All rights reserved. www.richtek.com 2 The RT2528 provides built-in soft-start function. The driver controls the gate voltage of the power switch. The driver incorporates circuitry that controls the rising time and falling time of the output voltage to limit large inrush current and voltage surges. The RT2528 enters constant-current mode when the load exceeds the current limit threshold. is a registered trademark of Richtek Technology Corporation. DS2528-03 November 2013 RT2528 Absolute Maximum Ratings         (Note 1) Supply Input Voltage, VIN ----------------------------------------------------------------------------------------------Other Pins ------------------------------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C SOP-8 (Exposed Pad) --------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2) SOP-8 (Exposed Pad), θJA ---------------------------------------------------------------------------------------------SOP-8 (Exposed Pad), θJC --------------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------Junction Temperature ----------------------------------------------------------------------------------------------------Storage Temperature Range -------------------------------------------------------------------------------------------ESD Susceptibility (Note 3) HBM (Human Body Model) ---------------------------------------------------------------------------------------------- Recommended Operating Conditions    −0.3V to 6V −0.3V to 6V 2.041W 49°C/W 8°C/W 260°C 150°C −65°C to 150°C 2kV (Note 4) Supply Input Voltage, VIN ----------------------------------------------------------------------------------------------- 2.5V to 5.5V Temperature Range Junction -------------------------------------------------------------------------------------------- −40°C to 125°C Ambient Temperature Range -------------------------------------------------------------------------------------------- −40°C to 85°C Electrical Characteristics (VIN = 5V, TA = −40°C to 85°C, unless otherwise specified) Parameter Symbol Test Conditions Min Typ Max Unit Shutdown Current ISHDN VEN = 0V, IOUT = 0A -- 1 5 A Quiescent Current IQ IOUT = 0A -- 120 300 A EN Input Voltage Logic-High VIH 1.2 -- -- Logic-Low VIL -- -- 0.4 -- 0.02 0.5 A 10 -- 65 k -- 1 10 A -- 160 -- °C EN Input Current IEN Current Limit Setting Resistor Range RILIM Reverse Leakage Current IREV Thermal Shutdown Threshold TSD Static Drain-Source On-State Resistance RDS(ON) IOUT = 0.2A -- 74 120 m Reverse Voltage Comparator Trip Point IREV_HYS VOUT  VIN 100 135 300 mV RILIM = 13k 1800 2000 2200 RILIM = 13k, TA = 25°C 1840 2000 2160 RILIM = 49.9k 468 520 572 2 7.5 14 Current Limit FAULT Deglitch ILIM VIN = 5.5V VEN = 0V or 5.5V V VOUT = 5V, VIN = 0V FAULT assertion or de-assertion due to over-current condition Copyright © 2013 Richtek Technology Corporation. All rights reserved. DS2528-03 November 2013 mA ms is a registered trademark of Richtek Technology Corporation. www.richtek.com 3 RT2528 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. θJC is measured at the exposed pad of the package. The PCB copper area with exposed pad is 70mm2. Note 3. Devices are ESD sensitive. Handling precaution is recommended. Note 4. The device is not guaranteed to function outside its operating conditions. Copyright © 2013 Richtek Technology Corporation. All rights reserved. www.richtek.com 4 is a registered trademark of Richtek Technology Corporation. DS2528-03 November 2013 RT2528 Typical Application Circuit VIN RFAULT 100k FAULT Signal Enable 1, 2 7, 8 VOUT VIN CIN COUT 10µF 22µF RT2528 RILIM 13k 3 ILIM 4 FAULT 5 6, 9 (Exposed Pad) EN GND VOUT Note : RILIM = 13kΩ for 2A Power Switch Operation Copyright © 2013 Richtek Technology Corporation. All rights reserved. DS2528-03 November 2013 is a registered trademark of Richtek Technology Corporation. www.richtek.com 5 RT2528 Typical Operating Characteristics Quiescent Current vs. Input Voltage 190 140 170 Quiescent Current (µA) 1 Quiescent Current (µA) 1 Quiescent Current vs. Temperature 150 130 120 110 100 90 VIN = 5V -25 0 25 50 75 100 130 110 90 70 50 80 -50 150 2.5 125 3 3.5 Temperature (°C) Shutdown Current vs. Temperature 4.5 5 5.5 Shutdown Current vs. Input Voltage 5 Shutdown Current (µA)1 4 Shutdown Current (µA)1 4 Input Voltage (V) 3 2 1 0 4 3 2 1 0 -50 -25 0 25 50 75 100 2.5 125 3 3.5 4 4.5 5 5.5 Input Voltage (V) Temperature (°C) On-Resistance vs. Temperature Current Limit vs. Temperature 2.2 150 130 2.1 120 110 Current Limit (A) On-Resistance (m Ω ) 140 VIN = 3.6V 100 90 80 70 VIN = 5V 60 2.0 1.9 1.8 50 RILIM = 13kΩ 1.7 40 -50 -25 0 25 50 75 100 Temperature (°C) Copyright © 2013 Richtek Technology Corporation. All rights reserved. www.richtek.com 6 125 -50 -25 0 25 50 75 100 125 Temperature (°C) is a registered trademark of Richtek Technology Corporation. DS2528-03 November 2013 RT2528 EN Threshold Voltage vs. Temperature UVLO vs. Temperature 1.6 3.0 2.6 2.4 1.2 UVLO (V) EN Threshold Voltage (V) 2.8 1.4 Rising 1.0 0.8 Falling Rising 2.2 2.0 Falling 1.8 1.6 1.4 0.6 1.2 0.4 1.0 -50 -25 0 25 50 75 100 125 -50 0 25 50 75 Temperature (°C) Temperature (°C) Power On from EN Power Off from EN VEN (5V/Div) VEN (5V/Div) VOUT (2V/Div) VOUT (2V/Div) I IN (2A/Div) I IN (2A/Div) VIN = 5V, COUT = 100μF, RILIM = 13kΩ, ROUT = 5Ω Time (500μs/Div) Short Circuit Protection Short Circuit Protection VOUT (5V/Div) FAULT (5V/Div) FAULT (5V/Div) I IN (2A/Div) I IN (2A/Div) Time (2.5ms/Div) Copyright © 2013 Richtek Technology Corporation. All rights reserved. November 2013 125 From 2A to Short Circuit VOUT (5V/Div) VIN = 5V, COUT = 150μF, RILIM = 13kΩ 100 VIN = 5V, COUT = 100μF, RILIM = 13kΩ, ROUT = 5Ω Time (500μs/Div) From Short Circuit to 2A DS2528-03 -25 VIN = 5V, COUT = 150μF, RILIM = 13kΩ Time (2.5ms/Div) is a registered trademark of Richtek Technology Corporation. www.richtek.com 7 RT2528 Short Circuit Protection Short Circuit Protection From 0A to Short Circuit From Short Circuit to 0A VOUT (5V/Div) VOUT (5V/Div) FAULT (5V/Div) FAULT (5V/Div) I IN (1A/Div) I IN (1A/Div) VIN = 5V, COUT = 150μF, RILIM = 13kΩ VIN = 5V, COUT = 150μF, RILIM = 13kΩ Time (2.5ms/Div) Time (2.5ms/Div) Current Limit Threshold vs. (VIN - VOUT) 600 2000 550 Current Limit Threshold (mA) Current Limit Threshold (mA) Current Limit Threshold vs. (VIN - VOUT) 2200 1800 1600 1400 1200 1000 800 600 400 200 VIN = 5.5V, RILIM = 13kΩ 500 450 400 350 300 250 200 150 100 50 VIN = 5.5V, RILIM = 49.9kΩ 0 0 0 200 400 600 800 VIN - VOUT (mV) Copyright © 2013 Richtek Technology Corporation. All rights reserved. www.richtek.com 8 1000 0 200 400 600 800 1000 VIN - VOUT (mV) is a registered trademark of Richtek Technology Corporation. DS2528-03 November 2013 RT2528 Application Information The RT2528 is a single P-MOSFET high side power switch with active high enable input, optimized for self powered and bus powered Universal Serial Bus (USB) applications. The switch's low R DS(ON) meets USB voltage drop requirements and a flag output is available to indicate fault conditions to the local USB controller. If output voltage drops under around 1/2 input voltage, the device enters re-soft start current fold-back mode until either thermal shutdown occurs or the fault is removed. The Table1 shows a recommended current limit value vs. RILIM resistor. Current Limit Threshold vs. RILIM 2750 2500 When a heavy load or short circuit situation occurs while the switch is enabled, large transient current may flow through the device. The RT2528 includes a current limit circuitry to prevent these large currents from damaging the MOSFET switch and the hub downstream ports. The RT2528 provides an adjustable current limit threshold between 0.5A and 2.5A (typ.) via an external resistor, RILIM, between 10kΩ and 49.9kΩ. Once the current limit threshold is exceeded, and output voltage doesn't drop over 1/2 input voltage, the device enters constant current mode. 2250 Current Limit (mA) Current Limiting and Short Circuit Protection 2000 1750 1500 1250 1000 750 500 250 10 15 20 25 30 35 40 45 50 RILIM (kΩ) Figure 1. Current Limit Threshold vs. RILIM Table 1. Recommended RILIM Resistor Selections Desired Nominal Current Limit (mA) Ideal Resistor (k) Closet 1% Resistor (k) 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 2500 52.5 43.5 37.2 32.4 28.7 25.8 23.4 21.4 19.7 18.5 17.3 16.2 15.2 14.4 13.6 12.9 12.3 11.8 11.3 10.8 10.3 52.3 43.2 37.4 32.4 28.7 26.1 23.2 21.5 19.6 18.7 17.4 16.2 15.0 14.3 13.7 13.0 12.4 11.8 11.3 10.7 10.0 Copyright © 2013 Richtek Technology Corporation. All rights reserved. DS2528-03 November 2013 Actual Limits (Include R Tolerance) IOS min (mA) IOS nom (mA) IOS max (mA) 443.9 501.6 562.4 535.1 604.6 674.1 616.0 696.0 776.0 708.7 800.8 892.9 797.8 901.5 1005.2 875.4 989.1 1102.8 982.1 1109.7 1237.3 1057.9 1195.4 1332.9 1158.0 1308.5 1459.0 1225.7 1385.0 1544.3 1317.3 1488.5 1659.7 1414.8 1598.7 1782.6 1528.1 1726.7 1925.3 1602.9 1811.2 2019.5 1673.1 1890.5 2107.9 1763.2 1992.3 2221.4 1848.5 2088.7 2328.9 1942.6 2195.0 2447.4 2028.4 2292.0 2555.6 2141.7 2420.0 2698.3 2292.2 2590.0 2887.9 is a registered trademark of Richtek Technology Corporation. www.richtek.com 9 RT2528 Fault Flag The RT2528 provides a FAULT signal pin which is an N-Channel open drain MOSFET output. This open drain output goes low when current exceeds current limit threshold. The FAULT output is capable of sinking a 1mA load to typically 180mV above ground. The FAULT 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 case of an over current condition, FAULT will be asserted only after the flag response delay time, tD, has elapsed. This ensures that FAULT is asserted 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, which induces a high transient inrush current that exceeds the current limit threshold. The FAULT response delay time, tD, is typically 7.5ms. Supply Filter/Bypass Capacitor A 10μF low-ESR ceramic capacitor connected from VIN to GND and located close to the device is strongly recommended to prevent input voltage drooping during hotplug events. However, higher capacitor values may be used to further reduce the voltage droop on the input. Without this bypass capacitor, an output short may cause sufficient ringing on the input (from source lead inductance) to destroy the internal control circuitry. Note that the input transient voltage must never exceed 6V as stated in the Absolute Maximum Ratings. Output Filter Capacitor A low-ESR 22μF ceramic capacitor connected between VOUT and GND is strongly recommended to meet the USB standard maximum droop requirement for the hub, VBUS. 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 by hot-insertion transients in downstream cables. 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 Copyright © 2013 Richtek Technology Corporation. All rights reserved. www.richtek.com 10 should have a low dissipation factor to allow decoupling at higher frequencies. Chip Enable Input The RT2528 don’t have auto discharge function. During shutdown condition, the supply current is 1μA typical. The maximum guaranteed voltage for a logic-low at the EN pin is 0.4V. A minimum guaranteed voltage of 1.2V at the EN pin will turn on the RT2528. Floating the input may cause unpredictable operation. Under Voltage Lockout Under Voltage Lockout (UVLO) prevents the MOSFET switch from turning on until input voltage exceeds approximately 2.2V. If input voltage drops below approximately 2V, UVLO turns off the MOSFET switch and FAULT will be asserted accordingly. The under voltage lockout detection functions only when the switch is enabled. Thermal Considerations For continuous operation, do not exceed absolute maximum junction temperature. The maximum power dissipation depends on the thermal resistance of the IC package, PCB layout, rate of surrounding airflow, and difference between junction and ambient temperature. The maximum power dissipation can be calculated by the following formula : PD(MAX) = (TJ(MAX) − TA) / θJA where TJ(MAX) is the maximum junction temperature, TA is the ambient temperature, and θJA is the junction to ambient thermal resistance. For recommended operating condition specifications, the maximum junction temperature is 125°C. The junction to ambient thermal resistance, θJA, is layout dependent. For SOP-8 (Exposed Pad) package, the thermal resistance, θJA, is 49°C/W on a standard JEDEC 51-7 four-layer thermal test board. The maximum power dissipation at TA = 25°C can be calculated by the following formula : PD(MAX) = (125°C − 25°C) / (49°C/W) = 2.041W for SOP-8 (Exposed Pad) package is a registered trademark of Richtek Technology Corporation. DS2528-03 November 2013 RT2528 Maximum Power Dissipation (W)1 The maximum power dissipation depends on the operating ambient temperature for fixed T J(MAX) and thermal resistance, θJA. The derating curve in Figure 2 allows the designer to see the effect of rising ambient temperature on the maximum power dissipation. 3.0 Layout Consideration   Four-Layer PCB Ounce copper on top layer will improve thermal performance. 4-layer PCB will be better. Place the shape with minimum 70mm2 as Figure 3 around the SOP-8 (Exposed Pad) footprint to achieve best thermal performance. 2.5 2.0 1.5 1.0 Copper Area = 70mm2, θJA = 49°C/W 0.5 Figure 3. PCB Copper Area 0.0 0 25 50 75 100 125 Ambient Temperature (°C) Figure 2. Derating Curve of Maximum Power Dissipation  Utilize standard PTH (Plated Through Hole, 25mil diameter, as Figure 4) to Via down from exposed pad on top layer to GND plane on other layers. Figure 4. Standard PTH to GND Plane Copyright © 2013 Richtek Technology Corporation. All rights reserved. DS2528-03 November 2013 is a registered trademark of Richtek Technology Corporation. www.richtek.com 11 RT2528 Outline Dimension H A M EXPOSED THERMAL PAD (Bottom of Package) Y J X 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 4.000 0.150 0.157 C 1.346 1.753 0.053 0.069 D 0.330 0.510 0.013 0.020 F 1.194 1.346 0.047 0.053 H 0.170 0.254 0.007 0.010 I 0.000 0.152 0.000 0.006 J 5.791 6.200 0.228 0.244 M 0.406 1.270 0.016 0.050 X 2.000 2.300 0.079 0.091 Y 2.000 2.300 0.079 0.091 X 2.100 2.500 0.083 0.098 Y 3.000 3.500 0.118 0.138 Option 1 Option 2 8-Lead SOP (Exposed Pad) Plastic Package Richtek Technology Corporation 14F, No. 8, Tai Yuen 1st 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. www.richtek.com 12 DS2528-03 November 2013