FPF2310/12/13/13L Dual-Output Adjustable Current Limit Switch Features Description 1.8 to 5.5V Input Voltage Range The FPF2310/12/13/13L are dual-channel load switches of the IntelliMAX™ family. The FPF2310/12/13/13L consist of dual, independent, current-limited, and slew rate controlled, P-channel MOSFET power switches. Slew rated turn-on prevents inrush current from glitching supply rails. The input voltage range operates from 1.8V to 5.5V to fulfill USB device supply requirements. Switch control is accomplished by a logic input (ON) capable of interfacing directly with low-voltage control signals. Typical RON = 75mΩ at IN = 5.5V 400~600mA Adjustable Current Limit 10% Current Limit Accuracy from Typical Slew Rate Controlled ESD Protected, Above 4000V HBM Independent Thermal Shutdown UVLO Output Discharge For the FPF2312, if the constant-current condition persists after 10ms, the part shuts down the switch. The FPF2310 has an auto-restart feature that turns the switch on again after 150ms if the ON pin is still active. FPF2313/13L remains in constant-current mode until the switch current falls below the current limit. For FPF2310 through FPF2313/13L, the minimum current limit is 400mA-600mA with 10% accuracy (+25°C) for each switch to comply with USB applications in portable devices. RoHS Compliant Applications Smart Phones FPF2310M/12/13/13L series is available in a spacesaving, 8-Lead, 3x3mm MLP. Enterprise Equipment Peripheral USB Ports and Accessories Related Resources FPF2310/12/13/13L Evaluation Board User Guide; Power Switch for USB Applications Figure 1. 8-Lead MLP (3x3mm) Ordering Information Part Number Minimum Current Limit Auto Current Blanking Restart Limit Time FPF2310MPX 400-600mA 10ms 150ms FPF2312MPX 400-600mA 10ms N/A Active HIGH Latch Off 8-Lead Molded Leadless Package FPF2313MPX 400-600mA 0ms N/A Active HIGH Constant 8-Lead Molded Leadless Package Current FPF2313LMPX 400-600mA 0ms N/A Active LOW Constant 8-Lead Molded Leadless Package Current © 2009 Fairchild Semiconductor Corporation FPF2310/12/13/13L • Rev. 1.1.3 ON Pin Activity Mode Active HIGH Restart Package 8-Lead Molded Leadless Package www.fairchildsemi.com FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch May 2010 ISETA IN ISETB FPF2310/12/13/13L* IN = 1.8V-5.5V CIN OFF ON ONA OFF ON ONB GND OUTA TO LOAD A OUTB TO LOAD B COUTB COUTA *FPF2313L is active LOW Figure 2. Typical Application Functional Block Diagram IN UVLO ONA CONTROL LOGIC A CURRENT LIMIT A OUTA THERMAL PROTECTION A OUTPUT DISCHARGE ISETA ONB CONTROL LOGIC B CURRENT LIMIT B OUTB THERMAL PROTECTION B OUTPUT DISCHARGE ISETB GND Figure 3. Block Diagram © 2009 Fairchild Semiconductor Corporation FPF2310/12/13/13L • Rev. 1.1.3 www.fairchildsemi.com 2 FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch Application Circuit ISETA 8 OUTA 7 1 GND 2 IN ONA 9 OUTB 6 3 ISETB 5 4 ONB MLP 3X3 8L Bottom View Figure 4. 8-Lead MLP 3x3mm (Bottom View) Pin Description Pin Name 1 GND Function Ground 2 IN 3 ONA Supply Input: Input to the power switch and the supply voltage for the IC. ON / OFF control input of power switch A. 4 ONB ON / OFF control input of power switch B. 5 ISETB Current limit set input for power switch B: A resistor from ISET to ground sets the current limit for the switch. 6 OUTB Switch Output: output of the power switch B. 7 OUTA Switch Output: output of the power switch A. 8 ISETA Current limit set input for power switch A: A resistor from ISET to ground sets the current limit for the switch. 9 Thermal Pad IC substrate, which can be connected to GND for better thermal performance. Do not connect to other pins. © 2009 Fairchild Semiconductor Corporation FPF2310/12/13/13L • Rev. 1.1.3 www.fairchildsemi.com 3 FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch Pin Configuration Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be operable above the recommended operating conditions and stressing the parts to these levels is not recommended. In addition, extended exposure to stresses above the recommended operating conditions may affect device reliability. The absolute maximum ratings are stress ratings only. Symbol Parameter IN, OUTA, OUTB, ON to GND PD TSTG Min. Max. Unit -0.3 6.0 V 0.6 Power Dissipation 2.2(2.) Storage Temperature ΘJA Thermal Resistance, Junction-to-Ambient ESD Electrostatic Discharge Protection (1.) -65 +150 216(1.) 57(2.) W °C °C/W Human Body Model, JESD22-A114 4000 V Charged Device Model, JESD22-C101 2000 V Notes: 1. Soldered thermal pad on a two-layer PCB without vias based on JEDEC STD 51-3. 2. Soldered thermal pad on a four-layer PCB without vias connected with GND plane based on JEDEC STD51-5, 7. Recommended Operating Range The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not recommend exceeding them or designing to absolute maximum ratings. Symbol Parameter Min. Max. Unit IN Supply Input 1.8 5.5 V TA Ambient Operating Temperature -40 +85 °C © 2009 Fairchild Semiconductor Corporation FPF2310/12/13/13L • Rev. 1.1.3 www.fairchildsemi.com 4 FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch Absolute Maximum Ratings IN = 1.8 to 5.5V, TA = -40 to +85°C unless otherwise noted. Typical values are at IN = 3.3V and TA = 25°C. Symbol Parameter Conditions Min. Typ. Max. Units Basic Operation VIN Operating Voltage 1.8 IQ Quiescent Current IN = 5.5V, IOUT = 0mA, VON = 5.5V (FPF2310/2/3), VON = 0V (FPF2313L) ISD IN Shutdown Current IN = 5.5V, OUTA = OUTB = Short to GND, VON = 0V (FPF2310/2/3), VON = 5.5V (FPF2313L) RON On Resistance RPD Output Pull-Down Resistance VIH ON Input Logic High Voltage (ON) VIL ON Input Logic Low Voltage ION ON Input Leakage VON = IN or GND ILIM Current Limit IN = 3.3V, OUTA = OUTB = 3V, RSET = 690Ω, TA = 25°C Shutdown Threshold 140 TSD Thermal Shutdown Return from Shutdown 130 VUVLO Under-Voltage Shutdown IN Increasing VUVLO_HYS Under-Voltage Shutdown Hysteresis 52.5 IN = 5.5V, IOUT = 200mA, TA = 25°C 75 IN = 5.5V, IOUT = 200mA, TA = -40°C to +85°C 90 IN = 3.3V, TA = 25°C VON = 0V (FPF2310/2/3), VON = 3.3V(FPF2313L) 70 IN = 1.8V 0.8 IN = 5.5V 1.4 5.5 V 94.5 μA 1 μA 140 mΩ Ω V IN = 1.8V 0.5 IN = 5.5V 0.9 -1 V 1 μA 550 mA Protections 450 Hysteresis 500 °C 10 1.55 1.65 1.75 V 50 mV 111 μs Dynamic tON Turn-On Time RL = 500Ω, CL = 0.1μF tOFF Turn-Off Time RL = 500Ω 5 μs tR OUTA, OUTB Rise Time RL = 500Ω, CL = 0.1μF 13 μs tF OUTA, OUTB Fall Time RL = 500Ω tBLANK Over-Current Blanking Time FPF2310, FPF2312 5 10 20 ms tRSTRT Auto-Restart Time FPF2310 75 150 300 ms Current Limit Response Time IN = 3.3V, Moderate Over-Current Condition tCLR OUT 2 90% μs 90% 10% 10% tR ON 20 μs tF 50% 50% 90% OUT 10% tDON tDOFF tON = tR + tDON tOFF = tF + tDOFF Figure 5. Timing Diagram © 2009 Fairchild Semiconductor Corporation FPF2310/12/13/13L • Rev. 1.1.3 www.fairchildsemi.com 5 FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch Electrical Characteristics 70.00 60.00 ONA = ONB = IN RSET = 698 Ohms 60.00 ONA = ONB = IN RSET = 698 Ohms 85°C 50.00 IN = 3.3V IQ CURRENT (uA) SUPPLY CURRENT (uA) 55.00 45.00 25°C 40.00 -40°C 35.00 30.00 50.00 IN = 5.5V 40.00 IN = 1.8V 30.00 20.00 10.00 25.00 0.00 -40 20.00 1.8 2.2 2.5 2.9 3.3 3.7 4.0 4.4 4.8 5.1 5.5 -15 Figure 6. Quiescent Current vs. Supply Voltage IN SHUTDOWN CURRENT (uA) IN SHUTDOWN CURRENT (uA) 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 -15 10 35 60 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 -40 85 -15 35 60 85 Figure 9. RON vs. Supply Voltage 110 85 IN = 5.5V ONA = ONB = 5.5V RSET = 698 Ohms IOUT = 200mA TA = 25°C PULL-DOWN RESISTANCE (Ohm) ON RESISTANCE (mOhm) 10 TJ, JUNCTION TEMPERATURE (°C) Figure 8. IN Shutdown Current vs. Temperature 80 RON B 70 RON A 60 50 -40 85 IN = 5.5V ON = OUT = 0V RSET = 698 Ohms 1.8 TJ, JUNCTION TEMPERATURE (°C) 90 60 2.0 IN = 5.5V ON = OUT = 0V RSET = 698 Ohms 1.8 100 35 Figure 7. Quiescent Current vs. Temperature 2.0 0.0 -40 10 TJ, JUNCTION TEMPERATURE (°C) SUPPLY VOLTAGE (V) -15 10 35 60 TJ, JUNCTION TEMPERATURE (°C) RPD A 75 RPD B 70 65 2.2 2.5 2.9 3.3 3.7 4.0 4.4 4.8 5.1 5.5 SUPPLY VOLTAGE (V) Figure 10. RON vs. Temperature Figure 11. RPD vs. Supply Voltage © 2009 Fairchild Semiconductor Corporation FPF2310/12/13/13L • Rev. 1.1.3 80 60 1.8 85 ONA = ONB = 0V RSET = 698 Ohms IOUT = 1mA TA = 25°C www.fairchildsemi.com 6 FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch Typical Characteristics 1.5 ON THRESHOLD VOLTAGE (V) PULL-DOWN RESISTANCE (Ohm) 80 75 RPDA 70 RPDB 65 60 IN = 5.5V ONA = ONB = 0V RSET = 698 Ohms IOUT = 1mA 55 50 -40 RSET = 698 Ohms TA = 25°C 1.3 1.0 VIH 0.8 VIL 0.5 0.3 0.0 -15 10 35 60 85 1.8 2.2 2.5 2.9 TJ, JUNCTION TEMPERATURE (°C) Figure 12. RPD vs. Temperature 3.7 4.0 4.4 5.1 5.5 1.4 1.2 1.0 ON THRESHOLD VOLTAGE (V) IN = 5.5V IN = 3.3V 0.8 IN = 1.8V 0.6 0.4 0.2 1.2 IN = 5.5V 1.0 IN = 3.3V 0.8 IN = 1.8V 0.6 0.4 0.2 RSET = 698 Ohms 0.0 -40 -15 10 35 60 RSET = 698 Ohms 0.0 -40 85 -15 TJ, JUNCTION TEMPERATURE (°C) 10 35 60 85 TJ, JUNCTION TEMPERATURE (°C) Figure 14. ON High Voltage vs. Temperature Figure 15. ON Low Voltage vs. Temperature 500 500 RSET = 698 Ohms TA = 25°C 498 495 CURRENT LIMIT (mA) CURRENT LIMIT (mA) 4.8 Figure 13. ON Threshold Voltage vs. Supply Voltage 1.4 ON THRESHOLD VOLTAGE (V) 3.3 SUPPLY VOLTAGE (V) ILIM(Typ)B 490 ILIM(Typ)A 485 496 494 IN = 3.3V OUTA = OUTB = 3V ONA = ONB = 3.3V RSET = 698 Ohms 492 ILIM(Typ)B 490 488 ILIM(Typ)A 486 484 482 480 1.8 2.2 2.5 2.9 3.3 3.7 4.0 4.4 4.8 5.1 480 -40 5.5 Figure 16. Current Limit vs. Supply Voltage 10 35 60 85 Figure 17. Current Limit vs. Temperature © 2009 Fairchild Semiconductor Corporation FPF2310/12/13/13L • Rev. 1.1.3 -15 TJ, JUNCTION TEMPERATURE (°C) SUPPLY VOLTAGE (V) www.fairchildsemi.com 7 FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch Typical Characteristics 20 IN = 3.3V RL = 500 Ohms CL = 0.1 uF RSET = 698 Ohms tDON 16 100 IN = 3.3V RL = 500 Ohms RSET = 698 Ohms 10 tDOFF tR 14 12 10 8 -15 10 35 60 4 tF 0 -40 85 -15 TJ, JUNCTION TEMPERATURE (°C) 180 10.5 OUTB 10.0 9.5 170 OUTA 160 150 OUTB 140 130 120 9.0 110 8.5 -40 -15 10 35 60 100 -40 85 -15 TJ, JUNCTION TEMPERATURE (°C) IN 5V/DIV ON 2V/DIV IN = 5V ON = 3.3V COUT = 0.1μF RL = 500Ω RSET = 680Ω IOUT 50mA/DIV 60 85 IN = 5V ON = 3.3V CIN = 10μF COUT = 0.1μF RL = 500Ω RSET = 680Ω OUT 5V/DIV 200μs/DIV 200μs/DIV Figure 22. tON Response Figure 23. tOFF Response © 2009 Fairchild Semiconductor Corporation FPF2310/12/13/13L • Rev. 1.1.3 35 Figure 21. tRSTRT vs. Temperature IN 5V/DIV ON 2V/DIV 10 TJ, JUNCTION TEMPERATURE (°C) Figure 20. tBLANK vs. Temperature OUT 5V/DIV 85 FPF2310 IN = 3.3V ONA = ONB = 3.3V RSET = 698 Ohms 190 OUTA 11.0 60 200 RESTART TIME (ms) BLANKING TIME (ms) 11.5 35 Figure 19. tRISE / tFALL vs. Temperature FPF2310/12 IN = 3.3V ONA = ONB = 3.3V RSET = 698 Ohms 12.0 10 TJ, JUNCTION TEMPERATURE (°C) Figure 18. tDON / tDOFF vs. Temperature 12.5 IN = 3.3V RL = 500 Ohms RSET = 698 Ohms 6 2 1 -40 IN = 3.3V RL = 500 Ohms CL = 0.1 uF RSET = 698 Ohms 18 RISE/FALL TIME (us) TURN ON/OFF DELAY TIME (us) 1000 www.fairchildsemi.com 8 FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch Typical Characteristics IN 5V/DIV IN 5V/DIV IN = 5V ON = 3.3 CIN = 10μF COUT = 10μF RL = 3.3Ω RSET = 680Ω ON 2V/DIV IOUT 500mA/DIV tBLANK OUT 5V/DIV IN = 5V ON = 3.3 CIN = 10μF COUT = 10μF RL = 3.3Ω RSET = 680Ω ON 2V/DIV IOUT 500mA/DIV OUT 5V/DIV 4ms/DIV 40ms/DIV Figure 24. tBLANK Response (FPF2310/12) Figure 25. tRSTRT Response (FPF2310) IN 5V/DIV IN 5V/DIV ON 2V/DIV IN = 5V ON = 3.3 ON 2V/DIV IN = 5V ON = 3.3V CIN = 10μF COUT = 47μF IOUT 500mA/DIV OUT 5V/DIV COUT = 47μF RL = 10Ω RSET = 680Ω OUT 5V/DIV COUT = 220μF COUT = 470μF 1ms/DIV 200μs/DIV Figure 27. Output Voltage Rise Time with Various Load Capacitor Figure 26. Current Limit Response with 47μF IN 5V/DIV IN 5V/DIV ON 2V/DIV ON 2V/DIV IOUT 500mA/DIV RL = 10Ω RSET = 680Ω COUT = 100μF IOUT 500mA/DIV COUT = 470μF COUT = 220μF IN = 5V ON = 3.3 RL = 10Ω RSET = 680Ω COUT = 100μF COUT = 47μF IOUT 500mA/DIV COUT = 470μF COUT = 220μF COUT = 100μF IN = 5V ON = 3.3 RL = 10Ω RSET = 680Ω COUT = 47μF 8μs/DIV 40μs/DIV Figure 28. Output Current Inrush at Startup with Various Load Capacitors Figure 29. Output Current Inrush at Startup with Various Load Capacitors © 2009 Fairchild Semiconductor Corporation FPF2310/12/13/13L • Rev. 1.1.3 www.fairchildsemi.com 9 FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch Typical Characteristics IN 5V/DIV ON 2V/DIV IN = 5V ON = 3.3 COUTA = 100μF COUTB = 100μF OUTA 500mV/DIV RLA = RLB = 1Ω RSET = 680Ω IN 5V/DIV IN = 5V CIN = 150μF COUT = 47μF CL = 150μF RL = 10Ω RSET = 680Ω ON 2V/DIV IOUT 2A/DIV OUTB 500mV/DIV OUT 5V/DIV 400μs/DIV 400μs/DIV Figure 30. Current Limit Response Time Both Channels are in OC Figure 31. Inrush Response During Capacitive Load Hot Plug-In Event IN 5V/DIV IN = 5V CIN = 150μF COUT = 100μF CL = 47μF RL = 10Ω RSET = 680Ω ON 2V/DIV IOUT 2A/DIV OUT 5V/DIV 400μs/DIV Figure 32. Inrush Response During Capacitive and Resistive Load Hot Plug-In Event © 2009 Fairchild Semiconductor Corporation FPF2310/12/13/13L • Rev. 1.1.3 www.fairchildsemi.com 10 FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch Typical Characteristics The FPF2310/2/3/3L are dual-output current-limit switches designed to meet notebook computer, peripheral USB port, and point-of-load (POL) application power requirements. Dual-output current can be used where two USB ports are powered by hosts or self-powered hubs. The FPF231X family offers control and protection while providing optimum operation current for safe design practices. The core of each switch is a 75mΩ (IN = 5.5V) P-channel MOSFET and a controller capable of functioning over an input operating range of 1.8 to 5.5V. The FPF231X offers current limiting, UVLO (under-voltage lockout), and thermal shutdown protection in each switch. In the event of an overcurrent condition, the load switch limits the load to current limit value. The current limit value for each switch can be adjusted through the ISET pins. 400mA-600mA is adjustable for the FPF2310 through FPF2313. The minimum current limit is 400mA-600mA with 10% accuracy at +25°C with minimum variation over temperature. ON VIN VOUT ILOAD tRSTRT ILIMIT Over current condtion On/Off Control Figure 33. FPF2310 Performance While Entering into an Over-Current Condition. The ON pin is active HIGH for FPF2310/2/3 and controls the state of the switch. Pulling the ON pin continuous to HIGH holds the switch in ON state. The switch moves into the OFF state when the ON pin is pulled LOW or if a fault is encountered. FPF2313L is active LOW and performs in reverse order. For all versions, an under-voltage on input voltage or a junction temperature in excess of 140°C overrides the ON control to turn off the switch. In addition, excessive currents cause the switch to turn off in the FPF2310 and FPF2312 after 10ms blanking time. The FPF2310 has an auto-restart feature that automatically turns the switch ON again after 150ms. For the FPF2312, the ON pin must be toggled to turn on the switch again. The FPF2313 and FPF2313L do not turn off in response to an over-current condition, but remain operating in a constant-current mode as long as ON is enabled and the thermal shutdown or UVLO is not activated. The ON pin does not have a pull-down or pull-up resistor and should not be left floating. Note: 3. An over-current condition signal loads the output with a heavy load current larger than ILIM value. ON VIN VOUT Current Limiting ILOAD The current limit ensures that the current through the switch doesn't exceed a maximum value, while not limiting at less than a minimum value. FPF231X family has dual-output load switches in one package. The current limit of each switch is adjustable through the an external resistor connected to the ISET pin. The current limit range is from 400mA to 600mA with 10% current limit tolerance. ILIMIT Therm al Sh wn utdo Dev ice Co ols O ff Over current condtion Figure 34. FPF2313 Performance While Entering into an Over-Current Condition The FPF2310 and FPF2312 have a blanking time of 10ms (tBLANK(Typ) = 10ms) during which the switch acts as a constant current source. Note: 4 If the over-current condition persists beyond the blanking time, the FPF2310 latches off and shuts the switch off. If the ON pin is kept active, an auto-restart feature releases the switch and turns the switch on again after a 150ms auto-restart time (tRSTRT). If the over-current condition persists beyond the blanking time, the FPF2312 has a latch-off feature that shuts the switch off. The switch is kept off until the ON pin is toggled. The FPF2313/3L have no current-limit blanking period, so remain in a constantcurrent state until the ON pin of the affected switch is deactivated or the thermal shutdown turns off the switch. © 2009 Fairchild Semiconductor Corporation FPF2310/12/13/13L • Rev. 1.1.3 RL*ILMIT tBLANK An over-current condition signal loads the output with a heavy load current larger than ILIM value. www.fairchildsemi.com 11 FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch Description of Operation Minimum Current Limit [mA] Typical Current Limit [mA] 511 607 674 742 10 536 578 643 707 10 562 552 613 674 10 RSET [Ω] The FPF2310/2/3 and FPF2313L family contains an 70Ω onchip output pull-down resistor for quick output discharge when the switch is turned off. This features become more attractive when an application requires a large output capacitor to be discharged when switch turns off. However, the OUT pin should not be connected directly to the battery source due to the discharge mechanism of the load switch. Maximum Tolerance Current (%) Limit [mA] 590 526 584 642 10 620 500 556 611 10 649 478 531 584 10 681 455 506 556 10 732 424 471 518 10 775 400 445 489 10 Thermal Shutdown The thermal shutdown protects the device from internally or externally generated excessive temperatures. Each switch has an individual thermal shutdown protection function and operates independently as adjacent switch temperature increases above 140°C. If one switch is in normal operation and shutdown protection of second switch is activated, the first channel continues to operate if the affected channel's heat stays confined. The over-temperature in one channel can shut down both switches due to rapidly generated excessive load currents resulting in very high power dissipation. Generally, a thermally improved board layout can provide heat sinking and allow heat to stay confined and not affect operation of the second switch. ILIMIT (mA) During an over-temperature condition, the affected switch is turned off. If the temperature of the die drops below the threshold temperature, the switch automatically turns on again. To avoid unwanted thermal oscillations, a 10°C (typical) thermal hysteresis is implemented between thermal shutdown entry and exit temperatures. If output of both switches are connected together and an excessive load current activates thermal protection of both, the controller can shutdown the switches after both outputs go LOW and turn on both channels again. This provides a simultaneous switch turn on. Thermal protection is for device protection and should not be used as regular application operation. RSET (Ω) Figure 35. ILIM vs. RSET Under-Voltage Lockout (UVLO) The under-voltage lockout feature turns off the switch if the input voltage drops below the under-voltage lockout threshold. With the ON pin is active (ON pin is pulled LOW), the input voltage rising above the under-voltage lockout threshold causes a controlled turn-on of the switch and limits current overshoot. The device detects the UVLO condition when input voltage goes below UVLO voltage, but remains above 1.3V (typical). ON device wake-up IN UVLO THRESHOLD RISE TIME OUT 90% VOUT 10% VOUT ILOAD ILIMIT Figure 36. Under-Voltage Lockout (UVLO) © 2009 Fairchild Semiconductor Corporation FPF2310/12/13/13L • Rev. 1.1.3 www.fairchildsemi.com 12 FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch Output Discharge Resistor Table 1: RSET Selection Guide ISETA ISETB IN Host (5V) 1µF OFF ON ONA OFF ON ONA FPF2310/2/3 OUTA GND Downstream USB Port 33µF Downstream USB Port OUTB 33µF Figure 37. Typical Application Input Capacitor Power Dissipation To limit the voltage drop on the input supply caused by transient inrush currents when the switch is turned on into discharged load capacitors or a short-circuit; an input capacitor, CIN, is recommended between IN and GND. The FPF2310/2/3/3L features a fast current limit response time of 20μs. An inrush current (also known as surge current) could occur during the current limit response time while the switch is responding to an over-current condition caused by large output capacitors. A 10μF ceramic capacitor, CIN, is required to provide charges for the inrush current and prevent input voltage drop at the turn on. Higher values of CIN to further reduce the voltage drop. During normal operation as a switch, the power dissipation of device is small and has little effect on the operating temperature of the part. The maximum power dissipation for both switches, while the switch is in normal operation, occurs just before both channels enter into current limit. This may be calculated using: PD_MAX(NormalOperation) = 2 x (ILIM(MIN))2 x RON(MAX) (4) For example, for a 5V application maximum normal operation power loss while both switches delivering output current up to 500mA (ILIM(MIN) = 500mA) can be calculated as: PD_MAX(NormalOperation)(IN = 5V) = 2 x (0.5)2 x 0.14 Output Capacitor A 0.1μF to 1μF capacitor, COUT, should be placed between the OUT and GND pins. This capacitor prevents parasitic board inductances from forcing output voltage below GND when the switch turns off. This capacitor should have a low dissipation factor. An X7R MLCC (Multilayer Ceramic Chip) capacitors is recommended. For the FPF2310 and FPF2312, the total output capacitance needs to be kept below a maximum value, COUT(MAX), to prevent the part from registering an over-current condition beyond the blanking time and shutdown. The maximum output capacitance for a giving input voltage can be determined from the following: ILIM(MIN) x tBLANK(MIN) (2) COUT(MAX) = VIN For example, in a 5V application and ILIM(MIN) = 500mA using RSET = 620Ω, COUT(MAX) can be determine as: 0.5A x 5ms (3) COUT(MAX)(IN = 5V) = 5 = = 70mW The maximum junction temperature should be limited to 125°C under normal operation. Junction temperature can be calculated using: (6) TJ = PD x RθJA + TA where: TJ is junction temperature; PD is power dissipation across the switch RθJA is thermal resistance, junction-to-ambient; and TA is ambient temperature For example, TJ(MAX)(Normal operation) for an MLP 3x3mm package with TA=25°C while both switches are delivering up to 1.1A, is calculated as: TJ(MAX)(NormalOperation) = PD_MAX(Normal Operation)(IN = 5V) x 216 + 25 = 40.12°C (7) 500μF © 2009 Fairchild Semiconductor Corporation FPF2310/12/13/13L • Rev. 1.1.3 (5) www.fairchildsemi.com 13 FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch Application Information 1µF OFF ON ONA OFF ON ONA FPF2310/2/3 OUTA GND Downstream USB Port OUTB 33µF Figure 38. Self-Power USB for High Current Demand PCB Layout Recommendations If the part goes into current limit, the maximum power dissipation occurs when the output of switch is shorted to ground. For the FPF2310, the power dissipation scales with the auto-restart time, tRSTRT, and the over-current blanking time, tBLANK. In this case, the maximum power dissipated for the FPF2310 is: tBLANK PD_MAX(CurrentLimit) = 2 x x IN(MAX) x ILIM(MAX) tBLANK + tRSTRT (8) For the best performance, all traces should be as short as possible. To be most effective, the input and output capacitors should be placed close to the device to minimize the effects that parasitic trace inductances may have on normal and shortcircuit operation. Using wide traces for IN, OUTs, and GND pins helps minimize parasitic electrical effects along with minimizing the case-to-ambient thermal impedance. Improving Thermal Performance of the FPF231X Family of Devices Which results in: PD_MAX(CurrentLimit) = 2 x 10 x 5.5 x 0.74 = 508mW (9) 10 + 150 Improper layout could result in higher junction temperature and triggering the thermal shutdown protection feature. This concern applies particularly to the FPF2313 and FPF2313L, where both channels operate in constant-current mode in the overload conditions and; during fault condition, the outputs are shorted, resulting to large voltage drop across switches. In this case, power dissipation of the switch (PD = (VIN - VOUT) x ILIM(MAX)) could exceed the maximum absolute power dissipation of part. Note that this is below the maximum package power dissipation and the thermal shutdown feature protection provides additional safety to protect the part from damage due to excessive heating. The junction temperature is only able to increase to the thermal shutdown threshold. Once this temperature has been reached, toggling ON has no effect until the junction temperature drops below the thermal shutdown exit temperature. For the FPF2313 and FPF2313L, a short on the both outputs causes both switches to operate in a constantcurrent state and dissipating a worst-case power of: PMAX = IN(MAX) x ILIM(MAX) = 2 x 5.5 x 0.74 = 8.14W The following techniques improve the thermal performance of this family of devices. These techniques are listed in order of the significance of impact. 1. Thermal performance of the load switch can be improved by connecting the DAP (Die Attach Pad) of MLP 3x3mm package to the GND plane of the PCB. (10) 2. Embedding two exposed through-hole vias into the DAP (pin 9) provides a path for heat to transfer to the back GND plane of the PCB. A drill size of round, 15 mils (0.4mm) with 1ounce copper plating is recommended to create appropriate solder reflow. A smaller size hole prevents the solder from penetrating into the via, resulting in device lift-up. Similarly, a larger via-hole consumes excessive solder and may result in voiding the DAP. As both FPF2313/3L outputs are connected to GND. This power dissipation is significant and activates both thermal shutdown blocks. The part cycles in and out of thermal shutdown as long as the ON pin is activated (pulled LOW) and the output short is present. If high current of over 1A is required to supply enough power to a downstream function, dual outputs can be tied together as shown in Figure 38. © 2009 Fairchild Semiconductor Corporation FPF2310/12/13/13L • Rev. 1.1.3 www.fairchildsemi.com 14 FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch ISETA ISETB IN Host (5V) 25mil Figure 39. Two Through-Hole Open Vias Embedded in DAP 3. The IN, OUTs, and GND pins dissipate most of the heat generated during a high-load current condition. The layout suggested in Figure 39 illustrates a proper layout for devices in MLP 3x3mm packages. IN, OUTs, and GND pins are connected to adequate copper so that heat may be transferred as efficiently as possible out of the device. The low-power FLAGB and ON pins’ traces may be laid-out diagonally from the device to maximize the area available to the ground pad. Placing the input and output capacitors as close to the device as possible also contributes to heat dissipation, particularly during high load currents. Figure 41. Top, SST, and AST Layers (MLP 3x3mm Package) Figure 42. Zoom In to Top Layer Figure 40. Proper Layout of Output and Ground Copper Area FPF231X Evaluation Board FPF231X evaluation board has components and circuitry to demonstrate FPF2310/2/3/3L load switches functions and features accommodating both MLP 3x3mm packages. The state of the each channel can be configured using J1 and J2 jumpers. In addition, both channels can be controlled by ONA and ONB test pins. Thermal performance of the board is improved using techniques recommended in the layout recommendations section. R3 and R4 resistors are used on the board to sink a light load current when switches are activated. Figure 43. Bottom and ASB Layers © 2009 Fairchild Semiconductor Corporation FPF2310/12/13/13L • Rev. 1.1.3 www.fairchildsemi.com 15 FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch 15mil FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch Dimensional Outline and Pad Layout Figure 44. 8-Lead Molded Leadless Package (MLP) Package drawings are provided as a service to customers considering Fairchild components. Drawings may change in any manner without notice. Please note the revision and/or date on the drawing and contact a Fairchild Semiconductor representative to verify or obtain the most recent revision. Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions, specifically the warranty therein, which covers Fairchild products. Always visit Fairchild Semiconductor’s online packaging area for the most recent package drawings: http://www.fairchildsemi.com/packaging/. © 2009 Fairchild Semiconductor Corporation FPF2310/12/13/13L • Rev. 1.1.3 www.fairchildsemi.com 16 FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch © 2009 Fairchild Semiconductor Corporation FPF2310/12/13/13L • Rev. 1.1.3 www.fairchildsemi.com 17