FPF2300/02/03 Dual-Output Current Limit Switch Features Description ! 1.8 to 5.5V Input Voltage Range The FPF2300/02/03 are dual-channel load switches of IntelliMAX™ family. The FPF2300/02/03 consist of dual, independent, current-limited, slew rate controlled, Pchannel 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 today's USB device supply requirements. Switch control is accomplished by a logic input (ON) capable of interfacing directly with low-voltage control signal. ! Typical RON = 75mΩ at IN = 5.5V ! 1.3A Current Limit (Typical) ! Slew Rate Controlled ! Reversed Current Blocking when Disabled ! ESD Protected, Above 4000V HBM ! Independent Thermal Shutdown ! UVLO ! RoHS Compliant For the FPF2302, if the constant current condition persists after 10ms, these parts shut down the switch and pull the fault signal pin (FLAGB) LOW. The FPF2300 has an auto-restart feature that turns the switch on again after 504ms if the ON pin is still active. For the FPF2303, a current limit condition immediately pulls the fault signal pin LOW and the part remains in the constant-current mode until the switch current falls below the current limit. For the FPF2300 through FPF2303, the current limit is typically 1.3A for each switch to align with notebook computing applications. FPF2300/02/03 is available in both SO8 and MLP 3X3mm 8-lead packages. Applications ! Notebook Computing ! Peripheral USB Ports ! Networking / USB Based Equiptment Figure 1. 8-Lead SOP Figure 2. 8-Lead MLP (3x3mm) Ordering Information Part Number Minimum Current Limit Current Blanking Time Eco Limit Status Auto Restart ON Pin Activity Mode Restart Package FPF2300MX 1100mA 10ms RoHS 504ms Active LOW 8-Lead SO8 FPF2302MX 1100mA 10ms RoHS N/A Active LOW Latch Off 8-Lead SO8 FPF2303MX 1100mA 0ms RoHS N/A Active LOW Constant 8-Lead SO8 Current FPF2300MPX 1100mA 10ms Green 504 Active LOW Restart 8-Lead Molded Leadless Package (MLP) FPF2302MPX 1100mA 10ms Green N/A Active LOW Latch Off 8-Lead Molded Leadless Package (MLP) FPF2303MPX 1100mA 0ms Green N/A Active LOW Constant 8-Lead Molded LeadCurrent less Package (MLP) For Fairchild’s definition of Eco Status, please visit: http://www.fairchildsemi.com/company/green/rohs_green.html. © 2009 Fairchild Semiconductor Corporation FPF2300/02/03 • Rev. 1.1.3 www.fairchildsemi.com FPF2300/02/03 — Dual-Output Current Limit Switch June 2009 FLAGB(A) IN IN = 1.8V-5.5V CIN FLAGB(B) FPF2300/2/3 OFF ON ONA OFF ON ONB GND OUTA TO LOAD A OUTB TO LOAD B COUTB COUTA Figure 3. Typical Application Functional Block Diagram IN UVLO ONA REVERSE CURRENT BLOCKING CONTROL LOGIC A CURRENT LIMIT A OUTA THERMAL PROTECTION A FLAGB(A) ONB REVERSE CURRENT BLOCKING CONTROL LOGIC B CURRENT LIMIT B OUTB THERMAL PROTECTION B FLAGB(B) GND Figure 4. Block Diagram © 2009 Fairchild Semiconductor Corporation FPF2300/02/03 • Rev. 1.1.3 www.fairchildsemi.com 2 FPF2300/02/03 — Dual-Output Current Limit Switch Application Circuit FPF2300/02/03 — Dual-Output Current Limit Switch Pin Configuration GND 1 8 FLAGB(A) IN 2 7 OUTA FLAGB(A) 8 OUTA 7 1 GND 2 IN ONA 9 ONA 3 6 OUTB ONB 4 5 FLAGB(B) SO8 OUTB 6 3 FLAGB(B) 5 4 ONB MLP 3X3mm 8-Lead Bottom View Figure 5. Pin Configurations Pin Description Pin # Name Function 1 GND 2 IN 3 ONA ON / OFF control input of power switch A. Active LOW 4 ONB ON / OFF control input of power switch B. Active LOW 5 FLAGB(B) 6 OUTB Switch Output: Output of the power switch B 7 OUTA Switch Output: Output of the power switch A 8 FLAGB(A) Fault Output A, Active LO, open drain output which indicates an over supply, UVLO and thermal shutdown. 9(MLP) Thermal Pad IC Substrate, which can be connected to GND for better thermal performance. Do not connect to other pins. Ground Supply Input: Input to the power switch and the supply voltage for the IC. Fault Output B, Active LO, open drain output which indicates an over supply, UVLO and thermal shutdown. © 2009 Fairchild Semiconductor Corporation FPF2300/02/03 • Rev. 1.1.3 www.fairchildsemi.com 3 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, ONA, ONB, FLAGB(A), FLAGB(B) to GND Min. Max. Unit -0.3 6.0 V 0.8(1) SO8 PD 1.4(2) Power Dissipation 0.6(3) MLP TSTG Storage Temperature 2.2(4) -65 92(2) Thermal Resistance, Junction-to-Ambient 216(3) MLP ESD Electrostatic Discharge Protection +150 °C 158(1) SO8 ΘJA W °C/W 57(4) Human Body Model, JESD22-A114 4000 Charged Device Model, JESD22-C101 2000 V Notes: 1. Two-layer PCB of 2s0p from JEDEC STD 51-3. 2. Four-layer PBD of 2s0p from JEDEC STD 51-7. 3. Soldered thermal pad on a two-layer PCB without vias based on JEDEC STD 51-3. 4. Soldered thermal pad on a four-layer with two vias connected with GND plane base on JEDEC STD 51-5, 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. IN Supply Input 1.8 5.5 V TA Ambient Operating Temperature -40 +85 °C © 2009 Fairchild Semiconductor Corporation FPF2300/02/03 • Rev. 1.1.3 Max. Unit www.fairchildsemi.com 4 FPF2300/02/03 — Dual-Output 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 IQ Quiescent Current IN = 5.5V, VONA = VONB = 0V, IOUT = 0mA 1.8 ISD IN Shutdown Current VONA = VONB = 5.5V, IN = 5.5V OUTA = OUTB = Short to GND, RON On Resistance VIH ON Input Logic High Voltage (ON) VIL ON Input Logic Low Voltage ION ON Input Leakage IN = 5.5V, IOUT = 200mA, TA = 25°C 75 IN = 5.5V, IOUT = 200mA, TA = -40°C to 85°C 90 IN = 1.8V 0.8 IN = 5.5V 1.4 5.5 V 94.5 μA 3 μA 140 0.5 IN = 5.5V 0.9 -1 1 IN = 5.5V, ISINK = 1mA 0.1 0.2 IN = 1.8V, ISINK = 1mA 0.15 0.30 FLAGB Output High Leakage Current IN = VON = 5V ILIM Current Limit IN = 3.3V, VOUTA = VOUTB = 3V, TA = 25°C TSD Thermal Shutdown mΩ V IN = 1.8V VON = IN or GND FLAGB Output Logic Low Voltage 52.5 V μA V 1 μA 1.5 A Protections 1.1 Shutdown Threshold 140 Return from Shutdown 130 Hysteresis VUVLO VUVLO_HYS Under-Voltage Shutdown 1.3 °C 10 IN Increasing 1.55 Under-Voltage Shutdown Hysteresis 1.65 1.75 V 50 mV 113.5 μs 6 μs Dynamic tON Turn-On Time RL = 500Ω, CL = 0.1μF tOFF Turn-Off Time RL = 500Ω tR tBLANK OUTA, OUTB Rise Time RL = 500Ω, CL = 0.1μF Over-Current Blanking Time FPF2300, FPF2302 5 FPF2303(5) 5 tRSTRT_BLANK Startup FLAGB Blanking Time 13.5 μs 10 20 ms 10 20 ms tRSRT Auto-Restart Time FPF2300 504 ms tCLR Current Limit Response Time IN = 3.3V, Moderate Over-Current Condition 20 μs Note: 5. FPF2303 has a 10ms startup FLAGB blanking time when the part is turned on via the ON pin to ensure transient load currents settle. OUT 90% 90% 10% 10% tR ON tF 50% 50% 90% OUT 10% tDON tDOFF tON = tR + tDON tOFF = tF + tDOFF Figure 6. Timing Diagram © 2009 Fairchild Semiconductor Corporation FPF2300/02/03 • Rev. 1.1.3 www.fairchildsemi.com 5 FPF2300/02/03 — Dual-Output Current Limit Switch Electrical Characteristics 70.00 70.00 ONA = ONB = 0V ONA = ONB = 0V 60.00 85°C 50.00 IQ CURRENT (uA) SUPPLY CURRENT (uA) 60.00 25°C 40.00 -40°C 30.00 20.00 10.00 0.00 1.8 IN = 5.5V 50.00 40.00 IN = 3.3V 30.00 IN = 1.8V 20.00 10.00 2.2 2.5 2.9 3.3 3.7 4.0 4.4 4.8 5.1 0.00 -40 5.5 SUPPLY VOLTAGE (V) -15 10 35 60 85 TJ, JUNCTION TEMPERATURE (°C) Figure 7. Quiescent Current vs. Supply Voltage Figure 8. Quiescent Current vs. Temperature 160 IN = ONA = ONB = 5.5V OUT = 0V 4.50 ONA = ONB = 0V IOUT = 200mA TA = 25°C 150 ON RESISTANCE (mOhms) IN SHUTDOWN CURRENT (uA) 5.00 4.00 3.50 3.00 2.50 2.00 1.50 1.00 140 130 120 110 100 0.50 RON B 90 RON A 80 70 0.00 -40 -15 10 35 60 60 1.8 85 2.2 2.5 2.9 TJ, JUNCTION TEMPERATURE (°C) Figure 9. IN Shutdown Current vs. Temperature ON RESISTANCE (mOhm) ON RESISTANCE (mOhms) 95 130 120 110 100 90 RON B 80 RON A 70 60 1.8 2.2 2.5 2.9 3.3 3.7 4.4 4.8 5.1 5.5 90 IN = 5.5V IOUT = 200mA ONA = ONB = 0V 85 80 RON B 75 70 RON A 65 60 55 4.0 4.4 4.8 5.1 50 -40 5.5 SUPPLY VOLTAGE (V) -15 10 35 60 85 TJ, JUNCTION TEMPERATURE (°C) Figure 11. RON vs. Temperature (SO8) Figure 12. RON vs. Temperature (MLP) © 2009 Fairchild Semiconductor Corporation FPF2300/02/03 • Rev. 1.1.3 4.0 100 ONA = ONB = 0V IOUT = 200mA TA = 25°C 140 3.7 Figure 10. RON vs. Supply Voltage (MLP) 160 150 3.3 SUPPLY VOLTAGE (V) www.fairchildsemi.com 6 FPF2300/02/03 — Dual-Output Current Limit Switch Typical Characteristics ON RESISTANCE (mOhm) 85 1.5 IN = 5.5V IOUT = 200mA ONA = ONB = 0V TA = 25°C ON THRESHOLD VOLTAGE (V) 90 80 75 RON B 70 65 RON A 60 55 50 -40 1.3 VIL 1.0 0.8 VIH 0.5 0.3 0.0 -15 10 35 60 85 1.8 2.2 2.5 2.9 TJ, JUNCTION TEMPERATURE (°C) Figure 13. RON vs. Temperature (SO8) 4.0 4.4 4.8 5.1 5.5 1.2 IN = 5.5V ON THRESHOLD VOLTAGE (V) ON THRESHOLD VOLTAGE (V) 3.7 Figure 14. ON Threshold Voltage vs. Supply Voltage 1.2 1.0 IN = 3.3V 0.8 IN = 1.8V 0.6 0.4 0.2 0.0 -40 -15 10 35 60 IN = 5.5V 1.0 0.8 IN = 3.3V 0.6 IN = 1.8V 0.4 0.2 0.0 -40 85 -15 Figure 15. ON High Voltage vs. Temperature 1350 1340 35 60 85 Figure 16. ON Low Voltage vs. Temperature 1350 TA = 25°C 1320 CURRENT LIMIT (mA) 1330 ILIM(Typ)A 1310 ILIM(Typ)B 1300 1290 1280 1270 1260 1250 1.8 10 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) CURRENT LIMIT (mA) 3.3 SUPPLY VOLTAGE (V) IN = 3.3V 1340 OUTA = OUTB = 3V 1330 ONA = ONB = 0V 1320 ILIM(Typ)A 1310 1300 ILIM(Typ)B 1290 1280 1270 1260 2.2 2.5 2.9 3.3 3.7 4.0 4.4 4.8 5.1 1250 -40 5.5 SUPPLY VOLTAGE (V) 10 35 60 85 TJ, JUNCTION TEMPERATURE (°C) Figure 17. Current Limit vs. Supply Voltage Figure 18. Current Limit vs. Temperature © 2009 Fairchild Semiconductor Corporation FPF2300/02/03 • Rev. 1.1.3 -15 www.fairchildsemi.com 7 FPF2300/02/03 — Dual-Output Current Limit Switch Typical Characteristics 20 18 IN = 3.3V RL = 500 Ohms CL = 0.1 uF tDON 100 10 16 RISE/FALL TIME (us) TURN ON/OFF DELAY TIME (us) 1000 IN = 3.3V RL = 500 Ohms tDOFF 14 IN = 3.3V RL = 500 Ohms CL = 0.1 uF tF IN = 3.3V RL = 500 Ohms 12 10 8 6 4 2 1 -40 -15 10 35 60 0 -40 85 -15 FPF2300/2 IN = 3.3V ONA = ONB = 0V 10.5 10.0 FLAGB(B) 9.5 FLAGB(A) 9.0 8.5 8.0 7.5 7.0 -40 -15 10 35 35 60 85 Figure 20. tRISE / tFALL vs. Temperature STARTUP FLAGB BLANKING TIME (ms) Figure 19. tDON / tDOFF vs. Temperature 11.0 10 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) OVER CURRENT BLANKING TIME (ms) tR 60 85 10.0 FPF2303 IN = 3.3V ONA = ONB = 0V 9.5 9.0 FLAGB(A) 8.5 FLAGB(B) 8.0 7.5 7.0 -40 -15 10 35 60 85 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 21. tBLANK vs. Temperature Figure 22. tRSTRT_BLANK vs. Temperature 620.0 FPF2300 IN = 3.3V ONA = ONB = 0V RESTART TIME (ms) 600.0 IN 2V/DIV 580.0 OUTA ON 2V/DIV 560.0 540.0 OUTB 520.0 500.0 -40 OUT 2V/DIV -15 10 35 60 85 200μs/DIV TJ, JUNCTION TEMPERATURE (°C) Figure 23. tRSTRT vs. Temperature Figure 24. tON Response © 2009 Fairchild Semiconductor Corporation FPF2300/02/03 • Rev. 1.1.3 IN = 5V ON = 3.3V COUT = 0.1μF RL = 500Ω www.fairchildsemi.com 8 FPF2300/02/03 — Dual-Output Current Limit Switch Typical Characteristics IN 2V/DIV ON 2V/DIV ON 2V/DIV FLAGB 2V/DIV tBLANK IOUT 1A/DIV IN = 5V ON = 3.3V COUT = 0.1μF RL = 500Ω OUT 2V/DIV IN = 5V COUT = 10μF RL = 2.8Ω OUT 5V/DIV 2ms/DIV 200μs/DIV Figure 25. tOFF Response Figure 26. Over-Current Blanking Time (FPF2300/2) COUT = 10μF RL = 3.3Ω ON 2V/DIV ON 2V/DIV tSTART_BLANK FLAGB 2V/DIV tRSTRT FLAGB 2V/DIV IOUT 1A/DIV IOUT 1A/DIV OUT 2V/DIV OUT 5V/DIV IN = 5V COUT = 10μF RL = 2.8Ω 100ms/DIV 2ms/DIV Figure 28. Auto-Restart Time (FPF2300) Figure 27. Startup FLAGB Blanking Time (FPF2303) IN 5V/DIV IN 5V/DIV IN = 5V ON = 3.3V RL = 5Ω ON 5V/DIV ON 5V/DIV COUT = 470μF IOUT 1A/DIV IN = 5V ON = 3.3V RL = 5Ω OUT 5V/DIV COUT = 220μF COUT = 47μF COUT = 220μF COUT = 100μF COUT = 470μF COUT = 100μF COUT = 47μF 200μs/DIV 200μs/DIV Figure 29. Current Limit at Startup with Different Output Capacitor Figure 30. Output Voltage at Startup with Different Output Capacitor © 2009 Fairchild Semiconductor Corporation FPF2300/02/03 • Rev. 1.1.3 www.fairchildsemi.com 9 FPF2300/02/03 — Dual-Output Current Limit Switch Typical Characteristics IN 5V/DIV IN 5V/DIV IN = 5V ON = 3.3V COUTA = 100μF COUTB = 100μF RLA = RLB = 1Ω ON 2V/DIV ON 2V/DIV OUTA 2V/DIV FLAGB(A) 2V/DIV OUTB 2V/DIV FLAGB(B) 2V/DIV 10ms/DIV 400μs/DIV Figure 32. Startup FLAGB Blanking Time Figure 31. Current Limit Response Time Both Channels are in OC IN 5V/DIV IN 5V/DIV IN = 5V COUT = 47μF CL = 470μF RL = 5Ω ON 5V/DIV IN = 5V CIN = 10μF COUT = 100μF CL = 47μF ON 5V/DIV IOUT 500mA/DIV IOUT 2A/DIV OUT 5V/DIV OUT 5V/DIV 200μs/DIV 1ms/DIV Figure 33. Inrush Response During Capacitive Load Hot Plug-In Event Figure 34. Inrush Response During Capacitive and Resistive Load Hot Plug-In Event © 2009 Fairchild Semiconductor Corporation FPF2300/02/03 • Rev. 1.1.3 IN = 5V ON = 3.3V COUTA = 100μF COUTB = 100μF RLA = RLB = 1Ω www.fairchildsemi.com 10 FPF2300/02/03 — Dual-Output Current Limit Switch Typical Characteristics The FPF2300, FPF2302, and FPF2303 are dual-output currentlimit switches designed to meet notebook computer, peripheral USB port, and point-of-load (POL) application power requirements. Dual-output current can be used where dual or quad USB ports are powered by hosts or self-powered hubs. The FPF230X family offers control and protection while providing optimum operation current for a safe design practice. The core of each switch is a typical 75mΩ (IN = 5.5V) P-channel MOSFET and a controller capable of functioning over an input operating range of 1.8-5.5V. The FPF230X family offers current limiting, UVLO (under-voltage lockout), and thermal shutdown protection per each switch. In the event of an over-current condition, the load switch limits the load to current limit value. The minimum current limit is set to 1100mA. startup blanking feature that prevents current faults related to startup transients from triggering the FLAGB output. The startup blanking feature is effective for the first 10ms (typical) following device turn-on via ON pin. The FLAGB outputs are two open-drain MOSFETs that require a pull-up resistor on each FLAGB pin. FLAGB can be pulled HIGH to a voltage source other than input supply with maximum 5.5V. A 100KΩ pull-up resistor is recommended. When the ON pin is inactive, the FLAGB is disabled to reduce current draw from the supply. If the FLAGB is not used, the FLAGB can be connected to ground on the PCB. . On/Off Control ON device wakeup The ON pin is active LOW for FPF2300/2/3 and controls the state of the switch. Pulling the ON pin continuous to LOW holds the switch in the ON state. The switch moves into the OFF state when the ON pin is pulled HIGH or if a fault is encountered. 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 FPF2300 and FPF2302 after a 10ms blanking time. The FPF2300 has an auto-restart feature that automatically turns the switch ON again after 504ms. For the FPF2302, the ON pin must be toggled to turn on the switch again. The FPF2303 does not turn off in response to an over-current condition, but remains 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. IN device wakeup FLAGB RISE TIME OUT 90% VOUT 10% VOUT ILOAD ILIMIT Figure 35. FLAGB Assertion in Under-Voltage Fault Current Limiting 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. FPF230X family has dual-output load switches being housed in one package. The minimum current at which both switches start limiting the load current is set to 1100mA. The FPF2300 and FPF2302 have a blanking time of 10ms (typical), during which the switch acts as a constant current source. At the end of the blanking time, the switch is turned off. The FPF2303 has no current limit blanking period, so it remains in a constant current state until the ON pin of the affected switch is deactivated or the thermal shutdown turns off the switch. ON VIN VOUT ILOAD ILIMIT Fault Reporting Over current Over-current, input under-voltage, and over-temperature fault conditions are signaled out by the FLAGB pin going LOW. A UVLO fault is reported on both FLAGB(A) and FLAGB(B) simultaneously, while over-current and over-temperature condition faults are reported independently. FPF2300 and FPF2302 have a current fault blanking feature that prevents over-current faults shorter than the blanking time (tBLANK(Typ) = 10ms) from triggering the fault signal (FLAGB) output. condtion FLAGB tBLANK tRSTRT Figure 36. FPF2300 FLAGB Reports While Entering into an Over-Current Condition Note: If the over-current condition persists beyond the blanking time, the FPF2300 pulls the FLAGB pin LOW and shuts the switch off. If the ON pin is kept active, an auto-restart feature releases the FLAGB pin and turns the switch on again after a 504ms auto-restart time (tRSTRT). If the over-current condition persists beyond the blanking time, the FPF2302 has a latch-off feature that pulls the FLAGB pin LOW and shuts the switch off. The switch is kept off and the FLAGB pin kept LOW until the ON pin is toggled. The FPF2303 responds to an overload condition by immediately pulling the FLAGB pin LOW and the switch remains in constant current mode until the output overload condition is removed. The FPF2303 has a 6. © 2009 Fairchild Semiconductor Corporation FPF2300/02/03 • Rev. 1.1.3 RL* ILMIT An over-current condition signal loads the output with a heavy load current larger than ILIM value. www.fairchildsemi.com 11 FPF2300/02/03 — Dual-Output Current Limit Switch Description of Operation If output of both switches are connected together and an excessive load current activates thermal protection of both, the controller can shut down the switches after both FLAGB outputs go LOW and turn on both channels again. This provides simultaneous switch turn on. Thermal protection is for device protection and should not be used as regular operation. VIN VOUT Therm al Sh wn utdo Dev ILOAD ice Co ILIMIT ols Off Input Capacitor Over current condtion 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 turn on. Higher values of CIN can be used to further reduce voltage drop. FLAGB Startup tBLANK Figure 37. FPF2300 FLAGB While and Over-Current Condition is Applied Note: 7. An over-current condition signal loads the output with a heavy load current larger than ILIMIT value. 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 active (ON pin pulled LOW), the input voltage rising above the under-voltage lockout threshold causes a controlled turn-on of the switch and limits current overshoot. If a device is in UVLO condition, both FLAGBs go LOW and indicate the fault condition. The device detects the UVLO condition when input voltage goes below UVLO voltage, but remains above 1.3V (typical). 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 FPF2300 and FPF2302, 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) (1) COUT(MAX) = VIN Reverse Current Blocking Each switch of FPF2300/2/3 has an independent reverse current blocking feature that protects input source against current flow from output to input. For a standard USB power design, this is an important feature that protects the USB host from being damaged due to reverse current flow on VBUS. To activate the reverse current blocking, the switch must be in OFF state (ON pins inactivated) so that no current flows from the output to the input. The FLAGB operation is independent of the reverse current blocking and does not report a fault condition if this feature is activated. For example, in a 5V application, COUT(MAX) can be determined as: 1.1A x 5ms (2) COUT(MAX)(IN = 5V) = 5 = Thermal Shutdown 1.1mF 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 temperatures increase 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 the second switch operation. During an over-temperature condition, the FLAGB is pulled LOW and the affected switch is turned off. If the temperature of the die drops below the threshold temperature, the switch © 2009 Fairchild Semiconductor Corporation FPF2300/02/03 • Rev. 1.1.3 www.fairchildsemi.com 12 FPF2300/02/03 — Dual-Output Current Limit 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. ON 10KΩ 10KΩ 33μF Host 5V FLAGB(A) IN FLAGB(B) FPF2300/2/3 1μF OFF ON ONA OFF ON ONB 33μF Downstream USB Port Downstream USB Port OUTA GND OUTB 33μF 33μF Downstream USB Port Downstream USB Port Figure 38. Self Powered 4-Port USB Hub Using a Single FPF230X capability per port required in actual power designs. FPF230X has 1.1A minimum current limit per output, which can cover two ports, as shown in Figure 38. Four USB ports can be implemented with a single FPF230X part and current limiting is provided based on a two-port basis for a cost-effective solution. FPF230X is designed to simplify USB port power design based on self-powering USB host/hub applications. A self-powering USB port is powered by a local 5V power supply, not by an upstream port. Each port should supply at least 500mA to each downstream function based on USB 2.0 specification. Implementation can depend on the number of USB ports and current 10KΩ 10KΩ Host 5V FLAGB(A) IN FLAGB(B) FPF2300/2/3 1μF OFF ON ONA OFF ON ONB 33μF Downstream USB Port OUTA GND OUTB 33μF Downstream USB Port 10KΩ 10KΩ FLAGB(A) IN FLAGB(B) FPF2300/2/3 1μF OFF ON ONA OFF ON ONB 33μF Downstream USB Port OUTA GND OUTB 33μF Downstream USB Port Figure 39. Individual Port Power Management for Self-Powered 4-Port USB Hub In Figure 39, each USB port is connected with each output. Four USB ports can be implemented with two FPF230X parts. Current limiting and control are provided based on a single port. Current capability per port has more headroom; up to a minimum of 1.1A per port. © 2009 Fairchild Semiconductor Corporation FPF2300/02/03 • Rev. 1.1.3 www.fairchildsemi.com 13 FPF2300/02/03 — Dual-Output Current Limit Switch Application Information 10KΩ Host 5V FLAGB(A) IN FLAGB(B) FPF2300/2/3 1μF OFF ON ONA OFF ON ONB OUTA GND OUTB 33μF Downstream USB Port Figure 40. Self-Powered USB Port for High Current Demand High current, over 2A, is sometimes required to supply enough power to downstream functions. As shown in Figure 40, a 2.2A minimum load current can be achieved by tying dual outputs together. Power Dissipation If the part goes into current limit, the maximum power dissipation occurs when the output of switch is shorted to ground. For the FPF2300 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 FPF2300 is:: tBLANK x IN(MAX) x ILIM(MAX) PD_MAX(CurrentLimit) = 2 x tBLANK + tRSTRT (7) During normal operation as a switch, the power dissipation of the 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 the formula: PD_MAX(Normal Operation) = 2 x (ILIM(MIN))2 x RON(MAX) (3) For example, for a 5V application, maximum normal operation power loss while both switches delivering output current up to 1.1A, can be calculated as: 2 PD_MAX(Normal Operation)(IN = 5V) = 2 x (1.1) x 0.14 = which results in: (4) PD_MAX(CurrentLimit) = 2 x 338mW 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 affect until the junction temperature drops below the thermal shutdown exit temperature. For the FPF2303, a short on both outputs causes both switches to operate in a constant current state and dissipate a worst-case power of: PMAX = 2 x IN(MAX) x ILIM(MAX) = 2 x 5.5 x1.5 = 16.5 W (9) The maximum junction temperature should be limited to 125°C under normal operation. Junction temperature can be calculated using the formula below: TJ = PD x RθJA + TA 10 x 5.5 x 1.5 = 321mW (8) 10 + 504 (5) where: TJ is junction temperature; PD is power dissipation across the switch; RθJA is thermal resistance junction to ambient of the package; TA is ambient temperature. As both FPF2303 outputs are connected to GND. For the example, TJ(MAX)(Normal operation) for an SO8 package with TA=25°C while both switches are delivering up to 1.1A is calculated as: TJ(MAX)(NormalOperation) (6) x 125 + 25 =P This power dissipation is significant and activates both thermal shutdown blocks and the part can cycle in and out of thermal shutdown as long as the ON pin is activated (pulled LOW) and the output short is present. D_MAX(Normal Operation)(IN = 5V) = 78.4°C © 2009 Fairchild Semiconductor Corporation FPF2300/02/03 • Rev. 1.1.3 www.fairchildsemi.com 14 FPF2300/02/03 — Dual-Output Current Limit Switch 10KΩ 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 and the case-toambient thermal impedance. Improving Thermal Performance Improper layout could result in higher junction temperature and triggering the thermal shutdown protection feature. This concern is particularly significant for the FPF2303, where both channels operate in constant current mode in the overload conditions and during fault condition the outputs are shorted, resulting in 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. 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. 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 1-ounce copper plating is recommended to create appropriate solder reflow. A smaller size hole prevents the solder from penetrating into the via, resulting in device liftup. Similarly, a larger via hole consumes excessive solder and may result in voiding of the DAP. Figure 42. Proper Layout of Output and Ground Copper Area 15mil 25mil Figure 41. 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. Figure 42 illustrates a proper layout for devices in MLP 3x3mm packages. IN, OUTs, and GND pins are connected to adequate copper so heat may be transferred as efficiently as possible out of the device. The low-power FLAGB and ON pin 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. © 2009 Fairchild Semiconductor Corporation FPF2300/02/03 • Rev. 1.1.3 www.fairchildsemi.com 15 FPF2300/02/03 — Dual-Output Current Limit Switch PCB Layout Recommendations The FPF230X evaluation board has components and circuitry to demonstrate FPF2300/2/3 load switch functions and features, accommodating both the MLP 3x3mm and SO8 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 pints. Thermal performance of the board is improved using techniques 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 44. Bottom and ASB Layers Figure 43. Top, SST and AST Layers (MLP 3x3mm and SO8) Figure 45. Zoom-In to Top Layer Releated Resources FPF2300/02/03 Evaluation Board User Guide; Power Switch for USB Applications © 2009 Fairchild Semiconductor Corporation FPF2300/02/03 • Rev. 1.1.3 www.fairchildsemi.com 16 FPF2300/02/03 — Dual-Output Current Limit Switch FPF230X Evaluation Board FPF2300/02/03 — Dual-Output Current Limit Switch Dimensional Outline and Pad Layout Figure 46. 8-Lead SO8 Package 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 FPF2300/02/03 • Rev. 1.1.3 www.fairchildsemi.com 17 FPF2300/02/03 — Dual-Output Current Limit Switch Dimensional Outline and Pad Layout Figure 47. 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 FPF2300/02/03 • Rev. 1.1.3 www.fairchildsemi.com 18 The following includes registered and unregistered trademarks and service marks, owned by Fairchild Semiconductor and/or its global subsidianries, and is not intended to be an exhaustive list of all such trademarks. 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Customers who inadvertently purchase counterfeit parts experience many problems such as loss of brand reputation, substandard performance, failed applications, and increased cost of production and manufacturing delays. Fairchild is taking strong measures to protect ourselves and our customers from the proliferation of counterfeit parts. Fairchild strongly encourages customers to purchase Fairchild parts either directly from Fairchild or from Authorized Fairchild Distributors who are listed by country on our web page cited above. Products customers buy either from Fairchild directly or from Authorized Fairchild Distributors are genuine parts, have full traceability, meet Fairchild's quality standards for handling and storage and provide access to Fairchild's full range of up-to-date technical and product information. Fairchild and our Authorized Distributors will stand behind all warranties and will appropriately address any warranty issues that may arise. Fairchild will not provide any warranty coverage or other assistance for parts bought from Unauthorized Sources. Fairchild is committed to combat this global problem and encourage our customers to do their part in stopping this practice by buying direct or from authorized distributors. PRODUCT STATUS DEFINITIONS Definition of Terms Datasheet Identification Product Status Definition Advance Information Formative / In Design Datasheet contains the design specifications for product development. Specifications may change in any manner without notice. Preliminary First Production Datasheet contains preliminary data; supplementary data will be published at a later date. Fairchild Semiconductor reserves the right to make changes at any time without notice to improve design. No Identification Needed Full Production Datasheet contains final specifications. Fairchild Semiconductor reserves the right to make changes at any time without notice to improve the design. Obsolete Not In Production Datasheet contains specifications on a product that is discontinued by Fairchild Semiconductor. The datasheet is for reference information only. Rev. I40 © 2009 Fairchild Semiconductor Corporation FPF2300/02/03 • Rev. 1.1.3 www.fairchildsemi.com 19 FPF2300/02/03 — Dual-Output Current Limit Switch TRADEMARKS