FAN6755 Highly Integrated Green-Mode PWM Controller Features Description Internal High-Voltage Startup This highly integrated PWM controller provides several features to enhance the performance of flyback converters. Frequency Hopping to Reduce EMI Emission Low Operating Current (Maximum: 2mA) Adaptive Decreasing of PWM Frequency to 23KHz at Light-Load condition to Improve Light-Load Efficiency To minimize standby power consumption, a proprietary adaptive green-mode function reduces switching frequency at light-load condition. To avoid acousticnoise problems, the minimum PWM frequency is set above 23kHz. This green-mode function enables the power supply to meet international power conservation ® requirements, such as Energy Star . With the internal high-voltage startup circuitry, the power loss caused by bleeding resistors is also eliminated. To further reduce power consumption, FAN6755 uses the BiCMOS process, which allows an operating current of only 2mA. The standby power consumption can be under 100mW for most of LCD monitor power supply designs. Fixed PWM Frequency: 65KHz Internal Leading-Edge Blanking Built-in Synchronized Slope Compensation Auto-Restart Protection : Feedback Open-Loop Protection (OLP), VDD Over-Voltage Protection (OVP), Over-Temperature Protection (OTP), and Line Over-Voltage Protection FAN6755 integrates a frequency-hopping function that reduces EMI emission of a power supply with minimum line filters. Its built-in synchronized slope compensation achieves a stable peak-current-mode control and improves noise immunity. The proprietary, external line compensation ensures constant output power limit over a wide AC input voltage range from 90VAC to 264VAC. Soft Gate Drive with Clamped Output Voltage: 18V VDD Under-Voltage Lockout (UVLO) Programmable Constant Power Limit (Full AC Input Range) Internal OTP Sensor with Hysteresis Build-in 5ms Soft-Start Function FAN6755 provides many protection functions. The internal feedback open-loop protection circuit protects the power supply from open feedback loop condition or output short condition. It also has line under-voltage protection (brownout protection) and over-voltage protection using an input voltage sensing pin (VIN). Input Voltage Sensing (VIN Pin) for Brown-in/out Protection with Hysteresis and Line Over-Voltage Protection Applications FAN6755 is available in a 7-pin SOP package. General-purpose switched-mode power supplies and flyback power converters, including: FAN6755 — Highly Integrated Green-Mode PWM Controller May 2010 LCD Monitor Power Supply Open-Frame SMPS Ordering Information Part Number Operating Temperature Range FAN6755MY -40 to +105°C Package 7-Lead, Small Outline Integrated Circuit (SOIC), Depopulated JEDEC MS-112, .150 Inch Body Packing Method Reel & Tape ENERGY STAR® is a registered trademark of the U.S. Department of Energy and the U.S. Environmental Protection Agency. © 2009 Fairchild Semiconductor Corporation FAN6755 • Rev. 1.0.1 www.fairchildsemi.com 1 Figure 1. Typical Application Internal Block Diagram Figure 2. © 2009 Fairchild Semiconductor Corporation FAN6755 • Rev. 1.0.1 FAN6755 — Highly Integrated Green-Mode PWM Controller Application Diagram Functional Block Diagram www.fairchildsemi.com 2 FAN6755 — Highly Integrated Green-Mode PWM Controller Marking Information 7 Z: Plant Code X: 1-Digit Year Code Y: 1-Digit Week Code TT: 2-Digit Die Run Code T: Package Type (M:SOP) P: Y=Green Package M: Manufacture Flow Code ZXYTT 6755 TPM 1 Figure 3. Top Mark Pin Configuration SOP-7 VIN 1 FB 2 SENSE GND Figure 4. 7 HV 3 6 VDD 4 5 GATE Pin Configuration (Top View) Pin Definitions Pin # Name Description 1 VIN Line-voltage detection. The line-voltage detection is used for brownout protection with hysteresis. Constant output power limit over universal AC input range is also achieved using this VIN pin. It is suggested to add a low-pass filter to filter out line ripple on the bulk capacitor. Pulling VIN HIGH also triggers auto-restart protection. 2 FB The signal from the external compensation circuit is fed into this pin. The PWM duty cycle is determined in response to the signal on this pin and the current-sense signal on the SENSE pin. 3 SENSE 4 GND Ground 5 GATE The totem-pole output driver. Soft-driving waveform is implemented for improved EMI. 6 VDD 7 HV Current sense. The sensed voltage is used for peak-current-mode control and cycle-by-cycle current limiting. Power supply. The internal protection circuit disables PWM output as long as VDD exceeds the OVP trigger point. For startup, this pin is pulled HIGH to the line input or bulk capacitor via resistors. © 2009 Fairchild Semiconductor Corporation FAN6755 • Rev. 1.0.1 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 Min. (1, 2) Max. Unit 30 V VVDD DC Supply Voltage VFB FB Pin Input Voltage -0.3 7.0 V SENSE Pin Input Voltage -0.3 7.0 V VVIN VIN Pin Input Voltage -0.3 7.0 V VHV HV Pin Input Voltage 700 V PD Power Dissipation (TA＜50°C) 400 mW ΘJA Thermal Resistance (Junction-to-Air) 150 °C/W TJ Operating Junction Temperature -40 +125 °C Storage Temperature Range -55 +150 °C +260 °C VSENSE TSTG TL ESD Lead Temperature (Wave Soldering or IR, 10 Seconds) Human Body Model, JEDEC: JESD22-A114 All Pins Except HV Pin 4.5 Charged Device Model, JEDEC: JESD22-C101 All Pins Except HV Pin 1.0 kV Notes: 1. All voltage values, except differential voltages, are given with respect to the network ground terminal. 2. Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. 3. ESD with HV pin CDM=1000V and HBM=500V. © 2009 Fairchild Semiconductor Corporation FAN6755 • Rev. 1.0.1 FAN6755 — Highly Integrated Green-Mode PWM Controller Absolute Maximum Ratings www.fairchildsemi.com 4 VDD=15V, TA=25°C, unless otherwise noted. Symbol Parameter Conditions Min. Typ. Max. Units 22 V 17 V VDD Section VOP VDD-ON Continuously Operating Voltage Start Threshold Voltage VDD-OFF Protection Mode UVLO Normal Mode IDD-ST Startup Current IDD-OP 15 16 9 10 11 V 6.8 7.8 8.8 V VDD-ON – 0.16V 30 µA Operating Supply Current VDD=15V, GATE Open 2 mA IDD-OLP Internal Sink Current VTH-OLP+0.1V 30 60 90 µA VDD-OLP Threshold Voltage on VDD for HV JFET Turn-On 6.5 7.5 8.0 V VDD-OVP VDD Over-Voltage Protection 25 26 27 V tD-VDDOVP VDD Over-Voltage Protection Debounce Time 75 125 200 µs FAN6755 — Highly Integrated Green-Mode PWM Controller Electrical Characteristics VDD Behavior Figure 5. Continued on the following page… © 2009 Fairchild Semiconductor Corporation FAN6755 • Rev. 1.0.1 www.fairchildsemi.com 5 VDD=15V, TA=25°C, unless otherwise noted. Symbol Parameter Conditions Min. Typ. Max. Units 2.0 3.5 5.0 mA 1 20 µA 62 65 68 ±4.5 ±5.2 ±5.9 20 23 26 KHz 4.20 5.05 5.90 ms HV Section IHV IHV-LC Supply Current Drawn from HV Pin Leakage Current after Startup VDC=120V, VDD=10µF, VDD=0V HV=700V, VDD=VDD- OFF+1V Oscillator Section fOSC Frequency in Normal Mode fOSC-G Green-Mode Frequency tH-OP Hopping Period Center Frequency Hopping Range KHz fDV Frequency Variation vs. VDD Deviation VDD=11V to 22V 5 % fDT Frequency Variation vs. Temperature Deviation TA=-40 to 85°C 5 % VIN Section VIN-OFF PWM Turn-Off Threshold Voltage 0.66 0.70 0.74 V VIN-ON PWM Turn-On Threshold Voltage VIN-OFF+ 0.17 VIN-OFF+ 0.20 VIN-OFF+ 0.23 V VIN-Protect PWM Protect Threshold Voltage 5.1 5.3 5.5 V tVIN-Protect PWM Protect Debounce Time 60 100 140 µs FAN6755 — Highly Integrated Green-Mode PWM Controller Electrical Characteristics Current-Sense Section VTH-P at VIN=1V Threshold Voltage for Current Limit VIN=1V 0.80 0.83 0.86 V VTH-P at VIN=3V Threshold Voltage for Current Limit VIN=3V 0.67 0.70 0.73 V 100 200 ns 240 290 340 ns 4.0 5.5 7.0 ms tPD Delay to Output tLEB Leading-Edge Blanking Time tSS Period During Soft-Start Time Startup Time VIN vs. VSENSE Figure 6. Continued on the following page… © 2009 Fairchild Semiconductor Corporation FAN6755 • Rev. 1.0.1 www.fairchildsemi.com 6 VDD=15V, TA=25°C, unless otherwise noted. Symbol Parameter Conditions Min. Typ. Max. Units 1/4.5 1/4.0 1/3.5 V/V Feedback Input Section AV Input Voltage to Current-Sense Attenuation ZFB Input Impedance VFB =4V 11 15 18 kΩ Output High Voltage FB Pin Open 5.1 5.3 5.5 V VFB-OPEN VFB-OLP FB Open-Loop Trigger Level 4.4 4.6 4.8 V tD-OLP Delay Time of FB Pin Open-loop Protection 45.0 62.5 70.0 ms VFB-N Green-Mode Entry FB Voltage 2.8 3.0 3.2 V VFB-G Green-Mode Ending FB Voltage VFB-N - 0.6 V VFB-ZDCR FB Threshold Voltage for Zero-Duty Recovery 1.6 1.8 2.0 V VFB-ZDC FB Threshold Voltage for Zero-Duty 1.4 1.6 1.8 V ZDC Hysterisis 0.12 0.15 0.19 V VFB-ZDCR VFB-ZDC PWM Frequency FAN6755 — Highly Integrated Green-Mode PWM Controller Electrical Characteristics fOSC fOSC-G VFB-ZDC VFB-ZDCR VFB-G Figure 7. VFB-N VFB VFB vs. PWM Frequency Continued on the following page… © 2009 Fairchild Semiconductor Corporation FAN6755 • Rev. 1.0.1 www.fairchildsemi.com 7 VDD=15V, TA=25°C, unless otherwise noted. Symbol Parameter Conditions Min. Typ. Max. Units 60 75 90 % 1.5 V GATE Section DCYMAX Maximum Duty Cycle VGATE-L Gate Low Voltage VDD=15V, IO=50mA VGATE-H Gate High Voltage VDD=12V, IO=50mA tr Gate Rising Time VDD=15V, CL=1nF 100 ns tf Gate Falling Time VDD=15V, CL=1nF 30 ns Gate Source Current VDD=15V, GATE=6V 700 mA Gate Output Clamping Voltage VDD=22V IGATESOURCE VGATECLAMP_1 8 V V 18 Over-Temperature Protection Section (OTP) TOTP TRestart Protection Junction Temperature Restart Junction Temperature (4) (5) 135 °C TOTP-25 °C Notes: 4. When activated, the output is disabled and the latch is turned off. 5. The threshold temperature for enabling the output again and resetting the latch after over-temperature protection has been activated. © 2009 Fairchild Semiconductor Corporation FAN6755 • Rev. 1.0.1 FAN6755 — Highly Integrated Green-Mode PWM Controller Electrical Characteristics www.fairchildsemi.com 8 Figure 8. Startup Current (IDD-ST) vs. Temperature Figure 9. Operation Supply Current (IDD-OP) vs. Temperature Figure 10. Start Threshold Voltage (VDD-ON) vs. Temperature Figure 11. Minimum Operating Voltage (VDD-OFF) vs. Temperature Figure 12. Supply Current Drawn from HV Pin (IHV) vs. Temperature Figure 13. HV Pin Leakage Current After Startup (IHV-LC) vs. Temperature Figure 14. Frequency in Normal Mode (fOSC) vs. Temperature Figure 15. Maximum Duty Cycle (DCYMAX) vs. Temperature © 2009 Fairchild Semiconductor Corporation FAN6755 • Rev. 1.0.1 FAN6755 — Highly Integrated Green-Mode PWM Controller Typical Performance Characteristics www.fairchildsemi.com 9 Figure 16. FB Open-Loop Trigger Level (VFB-OLP) vs. Temperature Figure 17. Delay Time of FB Pin Open-Loop Protection (tD-OLP) vs. Temperature VIN-ON VIN-OFF Figure 18. PWM Turn-Off Threshold Voltage (VIN-OFF & VIN-ON) vs. Temperature Figure 19. VDD Over-Voltage Protection (VDD-OVP) vs. Temperature FAN6755 — Highly Integrated Green-Mode PWM Controller Typical Performance Characteristics Figure 20. VIN vs. VLIMIT © 2009 Fairchild Semiconductor Corporation FAN6755 • Rev. 1.0.1 www.fairchildsemi.com 10 Startup Current Gate Output / Soft Driving For startup, the HV pin is connected to the line input (1N4007 / 100KΩ recommended) or bulk capacitor through a resistor, RHV. Startup current drawn from pin HV (typically 3.5mA) charges the hold-up capacitor through the diode and resistor. When the VDD capacitor level reaches VDD-ON, the startup current switches off. At this moment, the VDD capacitor only supplies the FAN6755 to maintain VDD before the auxiliary winding of the main transformer to provide the operating current. The BiCMOS output stage is a fast totem-pole gate driver. Cross conduction has been avoided to minimize heat dissipation, increase efficiency, and enhance reliability. The output driver is clamped by an internal 18V Zener diode to protect power MOSFET transistors against undesirable gate over voltage. A soft driving waveform is implemented to minimize EMI. Soft-Start For many applications, it is necessary to minimize the inrush current at startup. The built-in 5.5ms soft-start circuit significantly reduces the startup current spike and output voltage overshoot. Operating Current Operating current is around 2mA. The low operating current enables better efficiency and reduces the requirement of VDD hold-up capacitance. Slope Compensation Green-Mode Operation The sensed voltage across the current-sense resistor is used for peak-current-mode control and pulse-by-pulse current limiting. Built-in slope compensation improves stability and prevents sub-harmonic oscillation. FAN6755 inserts a synchronized positive-going ramp at every switching cycle. The proprietary green-mode function provides an offtime modulation to reduce the switching frequency in light-load and no-load conditions. The on time is limited for better abnormal or brownout protection. VFB, which is derived from the voltage feedback loop, is taken as the reference. Once VFB is lower than the threshold voltage, switching frequency is continuously decreased to the minimum green-mode frequency of around 23KHz. Constant Output Power Limit For constant output power limit over universal inputvoltage range, the peak-current threshold is adjusted by the voltage of the VIN pin. Since the VIN pin is connected to the rectified AC input line voltage through the resistive divider, a higher line voltage generates a higher VIN voltage. The threshold voltage decreases as VIN increases, making the maximum output power at high-line input voltage equal to that at low-line input. The value of R-C network should not be so large that it affects the power limit (shown in Figure 21). Usually, R and C should be less than 100Ω and 470pF, respectively. Current Sensing / PWM Current Limiting Peak-current-mode control is utilized to regulate output voltage and provide pulse-by-pulse current limiting. The switch current is detected by a sense resistor into the SENSE pin. The PWM duty cycle is determined by this current sense signal and VFB, the feedback voltage. When the voltage on the SENSE pin reaches around VCOMP=(VFB–0.6)/4, a switch cycle is terminated immediately. VCOMP is internally clamped to a variable voltage around 0.83V for output power limit. FAN6755 — Highly Integrated Green-Mode PWM Controller Functional Description Leading-Edge Blanking (LEB) Each time the power MOSFET is switched on, a turn-on spike occurs on the sense resistor. To avoid premature termination of the switching pulse, a leading-edge blanking time is built in. During this blanking period, the current-limit comparator is disabled and cannot switch off the gate driver. Under-Voltage Lockout (UVLO) The turn-on and turn-off thresholds are fixed internally at 16V and 7.8V in normal mode. During startup, the hold-up capacitor must be charged to 16V through the startup resistor to enable the IC. The hold-up capacitor continues to supply VDD before the energy can be delivered from auxiliary winding of the main transformer. VDD must not drop below 7.8V during startup. This UVLO hysteresis window ensures that the hold-up capacitor is adequate to supply VDD during startup. © 2009 Fairchild Semiconductor Corporation FAN6755 • Rev. 1.0.1 Figure 21. Current-Sense R-C Filter www.fairchildsemi.com 11 Limited Power Control VDD over-voltage protection prevents damage due to abnormal conditions. Once the VDD voltage is over the over-voltage protection voltage (VDD-OVP), and lasts for tD-VDDOVP, the PWM pulses are disabled. When the VDD voltage drops below the UVLO, PWM pulses start again. Over-voltage conditions are usually caused by open feedback loops. The FB voltage is saturated HIGH when the power supply output voltage drops below its nominal value and shut regulator (KA431) does not draw current through the opto-coupler. This occurs when the output feedback loop is open or output is short circuited. If the FB voltage is higher than a built-in threshold for longer than tD-OLP, PWM output is turned off. As PWM output is turned off, VDD begins decreasing since no more energy is delivered from the auxiliary winding. Brownout Protection Since the VIN pin is connected through a resistive divider to the rectified AC input line voltage, it can also be used for brownout protection. If VIN is less than 0.7V, the PWM output is shut off. When VIN reaches over 0.9V, the PWM output is turned on again. The hysteresis window for ON/OFF is around 0.2V. The brownout voltage setting is determined by the potential divider formed with RUpper and RLower. Equations to calculate the resistors are shown below: When VDD goes below the turn-off threshold (~7.8V), the controller is totally shut down. VDD is charged up to the turn-on threshold voltage of 16V through the startup resistor until PWM output is restarted. This protection feature continues as long as the over loading condition persists. This prevents the power supply from overheating due to overloading conditions. RLower × V AC 2 , (unit = V ) RLower + RUpper Noise on the current sense or control signal may cause significant pulse-width jitter, particularly in continuousconduction mode. Slope compensation helps alleviate this problem. Good placement and layout practices should be followed. Avoiding long PCB traces and component leads, locating compensation and filter components near the FAN6755, and increasing the power MOS gate resistance improve performance. VIN = Noise Immunity (1) Thermal Overload Protection Thermal overload protection limits total power dissipation. When the junction temperature exceeds TJ= +135°C, the thermal sensor signals the shutdown logic and turns off most of the internal circuitry. The thermal sensor turns internal circuitry on again after the IC’s junction temperature drops by 25°C. Thermal overload protection is designed to protect the FAN6755 in the event of a fault condition. For continual operation, do not exceed the absolute maximum junction temperature of TJ = +150°C. © 2009 Fairchild Semiconductor Corporation FAN6755 • Rev. 1.0.1 FAN6755 — Highly Integrated Green-Mode PWM Controller VDD Over-Voltage Protection www.fairchildsemi.com 12 R6 12V1 1 C7 N18 R7 12V L2 P1 2 12V C5 1 N1 N1A N2 3 C1 L1 4 2 M1 2 R1 L 1 ZD1 TX1 12 11 C2 C11 + R14 D3 VIN N5 N6 6 1 2 N3 11 N N17 D1 R4 N21 8 R5 N20 7 1 3 R2 4 C4 4 R3 AC IN N4 C3 N28 1 1 2 3 + C9 3 BD1 CN1 + C8 2 2 F1 R8 C10 N7 C6 5V1 1 P2 2 5V 2 10 9 3 2 D4 5V L3 R17 C15 + C14 2 + C13 C12 2 D5 1 R13 R9 N8 Q1 R10 N10 D2 1 N9 R11 3 2 N30 SGND N29 R15 R12 1 HV P3 R16 VIN U1 4 C16 HV 7 SENSE GND R20 VDD FB VDD GATE R19 6 1 3 VIN N12 5V1 N13 U2 5 R22 GATE FAN6755 R28 C17 C18 + 12V C19 K 3 SENSE 2 2 4 1 FB U3 N14 R21 N15 C20 R A R18 Figure 22. © 2009 Fairchild Semiconductor Corporation FAN6755 • Rev. 1.0.1 44W Flyback 12V/2A, 5V/4A Application Circuit 5V R23 R24 R26 R27 N16 R25 FAN6755 — Highly Integrated Green-Mode PWM Controller Applications Information www.fairchildsemi.com 13 Designator Part Type Designator Part Type BD1 BD 4A/600V Q1 MOS 9A/600V C1 YC 2200pF/Y1 R1 R 1.5MΩ 1/4W C2 YC 2200pF/Y1 R2 R 1.5MΩ 1/4W C3 XC 0.33µF/300V R3 R 10MΩ 1/4W C4 NC R4, R5, R6, R7 R 47Ω 1/4W C5 YC 2200pF/Y1 R8, R17, R25, R27 NC C6 CC 2200pF/100V R9 R 50KΩ 1/4W C7 CC 1000pF/100V R10 R 50KΩ 1/4W C8 EC 1000µF/25V R11 R 0Ω 1/8W C9 EC 470µF/25V R12 R 47Ω 1/8W C10 CC 100pF/50V R13 R 100KΩ 1/8W C11 EC 100µF/400V R14 R 0Ω 1/4W C12 C 1µF/50V R15 R 10KΩ 1/8W C13 EC 1000µF/10V R16 R 1Ω 1/8W C14 EC 470µF/10V R18 R 0Ω 1/8W C15 CC 100pF/50V R19 R 100Ω 1/8W C16 C 1nF/50V R20 R 1KΩ 1/8W C17 C 470pF/50V R21 R 4.7KΩ 1/8W C18 EC 47µF/50V R22 R 7.5KΩ 1/8W C19 C 0.01µF/50V R23 R 120KΩ 1/8W C20 C 0.1µF/50V R24 R 15KΩ 1/8W D1 FYP1010 R26 R 10KΩ 1/8W D2 1N4148 R28 R 0.43Ω 2W D3 FR107 TX1 800µH(ERL-28) D4 FR103 U1 IC FAN6755 D5 FYP1010 U2 IC PC817 ZD1 P6KE150A U3 IC TL431 F1 FUSE 4A/250V M1 VZ 9G L1 13mH L2 Inductor (2µH) L3 Inductor (2µH) © 2009 Fairchild Semiconductor Corporation FAN6755 • Rev. 1.0.1 FAN6755 — Highly Integrated Green-Mode PWM Controller Build of Materials www.fairchildsemi.com 14 3.81 5.00 4.80 A 0.65TYP 3.81 78 5 B 6.20 5.80 PIN ONE INDICATOR 1.75TYP 4.00 3.80 1 3.85 7.35 4 1.27 (0.33) 0.25 M 1.27 C B A LAND PATTERN RECOMMENDATION 0.25 0.10 SEE DETAIL A 1.75 MAX 0.25 0.19 C 0.10 0.51 0.33 0.50 x 45¢X 0.25 R0.10 FAN6755 — Highly Integrated Green-Mode PWM Controller Physical Dimensions C OPTION A - BEVEL EDGE GAGE PLANE R0.10 OPTION B - NO BEVEL EDGE 0.36 8¢X 0¢X 0.90 0.406 NOTES: UNLESS OTHERWISE SPECIFIED A) THIS PACKAGE CONFORMS TO JEDEC MS-012, VARIATION AA, ISSUE C, DATED MAY 1990 EXCEPT PIN# 7 IS REMOVED. B) ALL DIMENSIONS ARE IN MILLIMETERS. C) DIMENSIONS DO NOT INCLUDE MOLD FLASH OR BURRS. D) STANDARD LEAD FINISH: 200 MICROINCHES / 5.08 MICRONS MIN. LEAD/TIN (SOLDER) ON COPPER. E) DRAWING FILENAME : M07AREV2 SEATING PLANE (1.04) DETAIL A SCALE: 2:1 Figure 23. 7-Lead, Small Outline Package (SOP) 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 FAN6755 • Rev. 1.0.1 www.fairchildsemi.com 15 FAN6755 — Highly Integrated Green-Mode PWM Controller © 2009 Fairchild Semiconductor Corporation FAN6755 • Rev. 1.0.1 www.fairchildsemi.com 16