MC33363A High Voltage Switching Regulator The MC33363A is a monolithic high voltage switching regulator that is specifically designed to operate from a rectified 240 Vac line source. This integrated circuit features an on--chip 700 V / 1.5 A SENSEFETt power switch, 500 V active off--line startup FET, duty cycle controlled oscillator, current limiting comparator with a programmable threshold and leading edge blanking, latching pulse width modulator for double pulse suppression, high gain error amplifier, and a trimmed internal bandgap reference. Protective features include cycle--by--cycle current limiting, input undervoltage lockout with hysteresis, output overvoltage protection, and thermal shutdown. This device is available in a 16--lead dual--in--line and wide body surface mount packages. http://onsemi.com MARKING DIAGRAMS SO--16W DW SUFFIX CASE 751N 16 MC33363ADW AWLYYWWG 1 Features A WL YY WW G Enhanced Power Capability Over MC33363 On--Chip 700 V, 1.5 A SENSEFET Power Switch Rectified 240 Vac Line Source Operation On--Chip 500 V Active Off--Line Startup FET Latching PWM for Double Pulse Suppression Cycle--By--Cycle Current Limiting Input Undervoltage Lockout with Hysteresis Output Overvoltage Protection Comparator Trimmed Internal Bandgap Reference Internal Thermal Shutdown These are Pb--Free Devices* PIN CONNECTIONS Startup Input 1 VCC 3 AC Input Regulator Output 1 Startup Mirror VCC Reg 8 UVLO 6 OVP RT CT 7 PWM Latch OSC Driver S Q 3 Overvoltage Protection Input DC Output 16 4 13 5 12 RT 6 11 CT 7 10 Regulator Output 8 GND Startup Input = Assembly Location = Wafer Lot = Year = Work Week = Pb--Free Package 9 Power Switch Drain GND Overvoltage Protection Input Voltage Feedback Input Compensation (Top View) ORDERING INFORMATION 11 16 See detailed ordering and shipping information in the package dimensions section on page 7 of this data sheet. Power Switch Drain R PWM Ipk LEB Compensation Thermal 9 EA GND Figure 4, 5, 12, 13 This device contains 221 active 1. Simplified transistors. Application Semiconductor Components Industries, LLC, 2010 November, 2010 -- Rev. 8 10 Voltage Feedback Input *For additional information on our Pb--Free strategy and soldering details, please download the ON Semiconductor Soldering and Mounting Techniques Reference Manual, SOLDERRM/D. 1 Publication Order Number: MC33363A/D MC33363A MAXIMUM RATINGS (Note 1) Symbol Value Unit Power Switch (Pin 16) Drain Voltage Drain Current VDS IDS 700 1.5 V A Startup Input Voltage (Pin 1) Vin 500 V Power Supply Voltage (Pin 3) VCC 40 V Input Voltage Range Voltage Feedback Input (Pin 10) Compensation (Pin 9) Overvoltage Protection Input (Pin 11) RT (Pin 6) CT (Pin 7) VIR --1.0 to Vreg V Rating Thermal Characteristics -- P Suffix, Dual--In--Line Case 648E Thermal Resistance, Junction--to--Air Thermal Resistance, Junction--to--Case (Pins 4, 5, 12, 13) C/W RθJA RθJC 80 15 RθJA RθJC 95 15 Operating Junction Temperature TJ --25 to +150 C Storage Temperature Tstg --55 to +150 C DW Suffix, Surface Mount Case 751N Thermal Resistance, Junction--to--Air Thermal Resistance, Junction--to--Case (Pins 4, 5, 12, 13) Refer to Figures 17 and 18 for additional thermal information. Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability. 1. This device series contains ESD protection and exceeds the following tests: Human Body Model 2000 V per MIL--STD--883, Method 3015. Machine Model Method 150 V. ELECTRICAL CHARACTERISTICS (VCC = 20 V, RT = 10 k, CT = 390 pF, CPin8 = 1.0 mF, for typical values TJ = 25C, for min/max values TJ is the operating junction temperature range that applies (Note 2), unless otherwise noted) Symbol Min Typ Max Unit Output Voltage (IO = 0 mA, TJ = 25C) Vreg 5.5 6.5 7.5 V Line Regulation (VCC = 20 V to 40 V) Regline -- 30 500 mV Load Regulation (IO = 0 mA to 10 mA) Regload -- 44 200 mV Vreg 5.3 -- 8.0 V Characteristic REGULATOR (Pin 8) Total Output Variation over Line, Load, and Temperature OSCILLATOR (Pin 7) Frequency CT = 390 pF TJ = 25C (VCC = 20 V) TJ = Tlow to Thigh (VCC = 20 V to 40 V) CT = 2.0 nF TJ = 25C (VCC = 20 V) TJ = Tlow to Thigh (VCC = 20 V to 40 V) fOSC Frequency Change with Voltage (VCC = 20 V to 40 V) kHz 260 255 285 -- 310 315 60 59 67.5 -- 75 76 ΔfOSC/ΔV -- 0.1 2.0 kHz VFB 2.52 2.6 2.68 V Regline -- 0.6 5.0 mV IIB -- 20 500 nA AVOL -- 82 -- dB ERROR AMPLIFIER (Pins 9, 10) Voltage Feedback Input Threshold Line Regulation (VCC = 20 V to 40 V, TJ = 25C) Input Bias Current (VFB = 2.6 V) Open Loop Voltage Gain (TJ = 25C) 2. Tested junction temperature range for the MC33363A: Tlow = --25C Thigh = +125C http://onsemi.com 2 MC33363A ELECTRICAL CHARACTERISTICS (VCC = 20 V, RT = 10 k, CT = 390 pF, CPin8 = 1.0 mF, for typical values TJ = 25C, for min/max values TJ is the operating junction temperature range that applies (Note 2), unless otherwise noted) Characteristic Symbol Min Typ Max Unit Gain Bandwidth Product (f = 100 kHz, TJ = 25C) GBW -- 1.0 -- MHz Output Voltage Swing High State (ISource = 100 mA, VFB < 2.0 V) Low State (ISink = 100 mA, VFB > 3.0 V) VOH VOL 4.0 -- 5.3 0.2 -0.35 Input Threshold Voltage Vth 2.47 2.6 2.73 V Input Bias Current (Vin = 2.6 V) IIB -- 100 500 nA DC(max) DC(min) 48 -- 50 0 52 0 --- 7.5 -- 9.0 20 --- 0.25 -- 1.0 50 ERROR AMPLIFIER (Pins 9, 10) V OVERVOLTAGE DETECTION (Pin 11) PWM COMPARATOR (Pins 7, 9) Duty Cycle Maximum (VFB = 0 V) Minimum (VFB = 2.7 V) % POWER SWITCH (Pin 16) Drain--Source On--State Resistance (ID = 200 mA) TJ = 25C TJ = Tlow to Thigh RDS(on) Drain--Source Off--State Leakage Current (VDS = 650 V) TJ = 25C TJ = Tlow to Thigh ID(off) Ω mA Rise Time tr -- 50 -- ns Fall Time tf -- 50 -- ns Ilim 0.7 0.9 1.1 A 2.0 2.0 5.0 5.0 8.0 8.0 OVERCURRENT COMPARATOR (Pin 16) Current Limit Threshold (RT = 13 k) STARTUP CONTROL (Pin 1) Peak Startup Current (Vin = 50 V) (TJ = --25C to 100C) VCC = 0 V VCC = (Vth(on) -- 0.2 V) Istart mA Off--State Leakage Current (Vin = 50 V, VCC = 20 V) ID(off) -- 40 200 mA Vth(on) 11 14.9 18 V VCC(min) 7.5 9.5 11.5 V --- 0.27 3.4 0.5 5.0 UNDERVOLTAGE LOCKOUT (Pin 3) Startup Threshold (VCC Increasing) Minimum Operating Voltage After Turn--On TOTAL DEVICE (Pin 3) Power Supply Current Startup (VCC = 10 V, Pin 1 Open) Operating ICC 2. Tested junction temperature range for the MC33363A: Tlow = --25C Thigh = +125C http://onsemi.com 3 mA f OSC , OSCILLATOR FREQUENCY (Hz) 1.0 M CT = 100 pF I PK, POWER SWITCH PEAK DRAIN CURRENT (A) MC33363A VCC = 20 V TA = 25C 500 k C = 200 pF T 200 k CT = 500 pF 100 k 50 k 20 k CT = 1.0 nF CT = 2.0 nF CT = 5.0 nF CT = 10 nF 10 k 7.0 10 15 20 30 70 50 RT, TIMING RESISTOR (kΩ) 1.5 VCC = 20 V CT = 1.0 mF TA = 25C 1.0 0.8 0.6 0.4 0.3 0.2 0.15 7.0 A VOL, OPEN LOOP VOLTAGE GAIN (dB) Dmax, MAXIMUM OUTPUT DUTY CYCLE (%) 0.2 0.15 0.1 10 15 20 30 70 50 30 40 50 70 60 50 40 RC/RT Ratio Charge Resistor Pin 7 to Vreg 30 1.0 2.0 3.0 5.0 7.0 Figure 4. Oscillator Charge/Discharge Current versus Timing Resistor Figure 5. Maximum Output Duty Cycle versus Timing Resistor Ratio VCC = 20 V VO = 1.0 to 4.0 V RL = 5.0 MΩ CL = 2.0 pF TA = 25C 80 Gain 60 0 30 60 Phase 90 40 0 150 1.0 180 10 M 0 100 k 1.0 M Vref -- 2.0 2.0 10 k Source Saturation (Load to Ground) --1.0 120 1.0 k 10 0 20 100 70 VCC = 20 V CT = 2.0 nF TA = 25C RD/RT Ratio Discharge Resistor Pin 7 to GND TIMING RESISTOR RATIO 100 --20 10 20 RT, TIMING RESISTOR (kΩ) , EXCESS PHASE (DEGREES) Vsat , OUTPUT SATURATION VOLTAGE (V) I chg /I dscg , OSCILLATOR CHARGE/DISCHARGE CURRENT (mA) 0.3 0.08 7.0 15 Figure 3. Power Switch Peak Drain Current versus Timing Resistor VCC = 20 V TA = 25C 0.5 10 RT, TIMING RESISTOR (kΩ) Figure 2. Oscillator Frequency versus Timing Resistor 0.8 Inductor supply voltage and inductance value are adjusted so that Ipk turn--off is achieved at 5.0 ms. Sink Saturation (Load to Vref) VCC = 20 V TA = 25C GND 0 f, FREQUENCY (Hz) 0.2 0.4 0.6 0.8 IO, OUTPUT LOAD CURRENT (mA) Figure 6. Error Amp Open Loop Gain and Phase versus Frequency Figure 7. Error Amp Output Saturation Voltage versus Load Current http://onsemi.com 4 1.0 MC33363A VCC = 20 V AV = --1.0 CL = 10 pF TA = 25C 1.75 V 1.75 V 0.50 V 1.70 V 1.0 ms/DIV 1.0 ms/DIV Figure 8. Error Amplifier Small Signal Transient Response Figure 9. Error Amplifier Large Signal Transient Response 0 8 --20 Istart, STARTUP CURRENT (mA) VCC = 20 V RT = 10 k TA = 25C --40 --60 --80 0 4.0 8.0 12 16 20 VPin1 = 50 V TA = 25C 7 6 5 4 3 2 1 0 0 Ireg, REGULATOR SOURCE CURRENT (mA) 2 4 6 8 10 VCC, SUPPLY VOLTAGE (V) 8 7 VCC = 0 V TA = 25C 6 5 4 VCC = 14 V TA = 25C 3 2 1 0 0 10 12 Figure 11. Peak Startup Current versus Power Supply Voltage Figure 10. Regulator Output Voltage Change versus Source Current Istart, STARTUP CURRENT (mA) V reg, REGULATOR VOLTAGE CHANGE (mV) 0.5 V/DIV 3.00 V 20 mV/DIV 1.80 V VCC = 20 V AV = --1.0 CL = 10 pF TA = 25C 20 30 40 50 VPin1, STARTUP PIN VOLTAGE (V) Figure 12. Peak Startup Current versus Startup Input Voltage http://onsemi.com 5 14 ID = 200 mA 24 16 8.0 4.0 0 --50 Pulse tested at 5.0 ms with < 1.0% duty cycle so that TJ is as close to TA as possible. --25 0 75 100 125 40 0 1.0 COSS measured at 1.0 MHz with 50 mVpp. 10 100 1000 Figure 13. Power Switch Drain--Source On--Resistance versus Temperature Figure 14. Power Switch Drain--Source Capacitance versus Voltage 100 R JA , THERMAL RESISTANCE JUNCTION--TO--AIR ( C/W) CT = 390 pF CT = 2.0 nF 2.4 1.6 RT = 10 k Pin 1 = Open Pin 4, 5, 10, 11, 12, 13 = GND TA = 25C 0.8 10 0 20 30 L = 12.7 mm of 2.0 oz. copper. Refer to Figures 17 and 18. 10 1.0 0.01 40 0.1 1.0 10 100 VCC, SUPPLY VOLTAGE (V) t, TIME (s) Figure 15. Supply Current versus Supply Voltage Figure 16. DW and P Suffix Transient Thermal Resistance 2.8 PD(max) for TA = 50C 90 80 2.4 Printed circuit board heatsink example 70 60 1.6 2.0 oz Copper L L 3.0 mm Graphs represent symmetrical layout 50 RθJA 10 1.2 0.8 0.4 40 0 2.0 20 30 40 0 50 100 R JA, THERMAL RESISTANCE JUNCTION--TO--AIR ( C/W) 100 30 80 VDS, DRAIN--SOURCE VOLTAGE (V) 3.2 0 120 150 PD, MAXIMUM POWER DISSIPATION (W) I CC, SUPPLY CURRENT (mA) 50 VCC = 20 V TA = 25C TA, AMBIENT TEMPERATURE (C) 3.6 R JA , THERMAL RESISTANCE JUNCTION--TO--AIR ( C/W) 25 160 5.0 Printed circuit board heatsink example 80 L RθJA 60 4.0 2.0 oz Copper L 3.0 mm Graphs represent symmetrical layout 3.0 40 2.0 PD(max) for TA = 70C 20 0 P D , MAXIMUM POWER DISSIPATION (W) 32 COSS, DRAIN--SOURCE CAPACITANCE (pF) R DS(on), DRAIN--SOURCE ON--RESISTANCE ( ) MC33363A 0 10 20 1.0 30 40 50 0 L, LENGTH OF COPPER (mm) L, LENGTH OF COPPER (mm) Figure 17. DW Suffix (SOP--16L) Thermal Resistance and Maximum Power Dissipation versus P.C.B. Copper Length Figure 18. P Suffix (DIP--16) Thermal Resistance and Maximum Power Dissipation versus P.C.B. Copper Length http://onsemi.com 6 MC33363A PIN FUNCTION DESCRIPTION Pin Function Description 1 Startup Input This pin connects directly to the rectified ac line voltage source. Internally Pin 1 is tied to the drain of a high voltage startup MOSFET. During startup, the MOSFET supplies internal bias, and charges an external capacitor that connects from the VCC pin to ground. 2 -- This pin has been omitted for increased spacing between the rectified ac line voltage on Pin 1 and the VCC potential on Pin 3. 3 VCCCC This is the positive supply voltage input. During startup, power is supplied to this input from Pin 1. When VCC reaches the UVLO upper threshold, the startup MOSFET turns off and power is supplied from an auxiliary transformer winding. 4, 5, 12, 13 GND 6 RT Resistor RT connects from this pin to ground. The value selected will program the Current Limit Comparator threshold and affect the Oscillator frequency. 7 CT Capacitor CT connects from this pin to ground. The value selected, in conjunction with resistor RT, programs the Oscillator frequency. 8 Regulator Output This 6.5 V output is available for biasing external circuitry. It requires an external bypass capacitor of at least 1.0 mF for stability. 9 Compensation This pin is the Error Amplifier output and is made available for loop compensation. It can be used as an input to directly control the PWM Comparator. 10 Voltage Feedback Input 11 Overvoltage Protection Input This input provides runaway output voltage protection due to an external component or connection failure in the control loop feedback signal path. It has a 2.6 V threshold and normally connects through a resistor divider to the converter output, or to a voltage that represents the converter output. 14, 15 -- These pins have been omitted for increased spacing between the high voltages present on the Power Switch Drain, and the ground potential on Pins 12 and 13. 16 Power Switch Drain These pins are the control circuit grounds. They are part of the IC lead frame and provide a thermal path from the die to the printed circuit board. This is the inverting input of the Error Amplifier. It has a 2.6 V threshold and normally connects through a resistor divider to the converter output, or to a voltage that represents the converter output. This pin is designed to directly drive the converter transformer and is capable of switching a maximum of 700 V and 1.0 A. ORDERING INFORMATION Package Shipping† MC33363ADWG SOIC--16WB (Pb--Free) 47 Units / Rail MC33363ADWR2G SOIC--16WB (Pb--Free) 1000 / Tape & Reel Device †For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specifications Brochure, BRD8011/D. http://onsemi.com 7 MC33363A AC Input Startup Input Current Mirror Regulator Output 6.5 V 8 Startup Control Band Gap Regulator I VCC 2.25 I CT 7 OVP Oscillator Overvoltage Protection Input 14.5 V/ 9.5 V 4I DC Output 3 UVLO 6 RT 1 11 2.6 V 16 PWM Latch Power Switch Drain Driver S Q R PWM Comparator Thermal Shutdown Leading Edge Blanking Current Limit Comparator Compensation 450 270 A Gnd 6.0 9 Error Amplifier 2.6 V 4, 5, 12, 13 10 Voltage Feedback Input Figure 19. Representative Block Diagram 2.6 V Capacitor C T 0.6 V Compensation Oscillator Output PWM Comparator Output PWM Latch Q Output Current Limit Propagation Delay Power Switch Gate Drive Current Limit Threshold Leading Edge Blanking Input (Power Switch Drain Current) Normal PWM Operating Range Figure 20. Timing Diagram http://onsemi.com 8 Output Overload MC33363A OPERATING DESCRIPTION Introduction The formula for the charge/discharge current along with the oscillator frequency are given below. The frequency formula is a first order approximation and is accurate for CT values greater than 500 pF. For smaller values of CT, refer to Figure 2. Note that resistor RT also programs the Current Limit Comparator threshold. The MC33363A represents a new higher level of integration by providing all the active high voltage power, control, and protection circuitry required for implementation of a flyback or forward converter on a single monolithic chip. This device is designed for direct operation from a rectified 240 Vac line source and requires a minimum number of external components to implement a complete converter. A description of each of the functional blocks is given below, and the representative block and timing diagrams are shown in Figures 19 and 20. I The MC33363A uses cycle--by--cycle current limiting as a means of protecting the output switch transistor from overstress. Each on--cycle is treated as a separate situation. Current limiting is implemented by monitoring the output switch current buildup during conduction, and upon sensing an overcurrent condition, immediately turning off the switch for the duration of the oscillator ramp--up period. The Power Switch is constructed as a SENSEFET allowing a virtually lossless method of monitoring the drain current. It consists of a total of 2819 cells, of which 65 are connected to a 6.0 Ω ground--referenced sense resistor. The Current Sense Comparator detects if the voltage across the sense resistor exceeds the reference level that is present at the inverting input. If exceeded, the comparator quickly resets the PWM Latch, thus protecting the Power Switch. The current limit reference level is generated by the 2.25 I output of the Current Mirror. This current causes a reference voltage to appear across the 450 Ω resistor. This voltage level, as well as the Oscillator charge/discharge current are both set by resistor RT. Therefore when selecting the values for RT and CT, RT must be chosen first to set the Power Switch peak drain current, while CT is chosen second to set the desired Oscillator frequency. A graph of the Power Switch peak drain current versus RT is shown in Figure 3 with the related formula below. 2.25 I I RC Current Limit Reference 6 RT RD Current Limit Comparator and Power Switch Current Mirror 8 CT 4I 7 Oscillator chg∕dscg 4C T The pulse width modulator consists of a comparator with the oscillator ramp voltage applied to the non--inverting input, while the error amplifier output is applied into the inverting input. The Oscillator applies a set pulse to the PWM Latch while CT is discharging, and upon reaching the valley voltage, Power Switch conduction is initiated. When CT charges to a voltage that exceeds the error amplifier output, the PWM Latch is reset, thus terminating Power Switch conduction for the duration of the oscillator ramp--up period. This PWM Comparator/Latch combination prevents multiple output pulses during a given oscillator clock cycle. The timing diagram shown in Figure 20 illustrates the Power Switch duty cycle behavior versus the Compensation voltage. The oscillator frequency is controlled by the values selected for the timing components RT and CT. Resistor RT programs the oscillator charge/discharge current via the Current Mirror 4 I output, Figure 4. Capacitor CT is charged and discharged by an equal magnitude internal current source and sink. This generates a symmetrical 50% duty cycle waveform at Pin 7, with a peak and valley threshold of 2.6 V and 0.6 V respectively. During the discharge of CT, the oscillator generates an internal blanking pulse that holds the inverting input of the AND gate driver high. This causes the Power Switch gate drive to be held in a low state, thus producing a well controlled amount of output deadtime. The amount of deadtime is relatively constant with respect to the oscillator frequency when operating below 1.0 MHz. The maximum Power Switch duty cycle at Pin 16 can be modified from the internal 50% limit by providing an additional charge or discharge current path to CT, Figure 21. In order to increase the maximum duty cycle, a discharge current resistor RD is connected from Pin 7 to ground. To decrease the maximum duty cycle, a charge current resistor RC is connected from Pin 7 to the Regulator Output. Figure 5 shows an obtainable range of maximum output duty cycle versus the ratio of either RC or RD with respect to RT. 1.0 f ≈ PWM Comparator and Latch Oscillator and Current Mirror Regulator Output I 5.4 = R chg∕dscg T Blanking Pulse I PWM Comparator pk = 15.95 RT -- 1.14 1000 The Power Switch is designed to directly drive the converter transformer and is capable of switching a Figure 21. Maximum Duty Cycle Modification http://onsemi.com 9 MC33363A Startup Control maximum of 700 V and 1.0 A. Proper device voltage snubbing and heatsinking are required for reliable operation. A Leading Edge Blanking circuit was placed in the current sensing signal path. This circuit prevents a premature reset of the PWM Latch. The premature reset is generated each time the Power Switch is driven into conduction. It appears as a narrow voltage spike across the current sense resistor, and is due to the MOSFET gate to source capacitance, transformer interwinding capacitance, and output rectifier recovery time. The Leading Edge Blanking circuit has a dynamic behavior in that it masks the current signal until the Power Switch turn--on transition is completed. The current limit propagation delay time is typically 300 ns. This time is measured from when an overcurrent appears at the Power Switch drain, to the beginning of turn--off. An internal Startup Control circuit with a high voltage enhancement mode MOSFET is included within the MC33363A. This circuitry allows for increased converter efficiency by eliminating the external startup resistor, and its associated power dissipation, commonly used in most off--line converters that utilize a UC3842 type of controller. Rectified ac line voltage is applied to the Startup Input, Pin 1. This causes the MOSFET to enhance and supply internal bias as well as charge current to the VCC bypass capacitor that connects from Pin 3 to ground. When VCC reaches the UVLO upper threshold of 15.2 V, the IC commences operation and the startup MOSFET is turned off. Operating bias is now derived from the auxiliary transformer winding, and all of the device power is efficiently converted down from the rectified ac line. Error Amplifier Regulator An fully compensated Error Amplifier with access to the inverting input and output is provided for primary side voltage sensing, Figure 19. It features a typical dc voltage gain of 82 dB, and a unity gain bandwidth of 1.0 MHz with 78 degrees of phase margin, Figure 6. The noninverting input is internally biased at 2.6 V 3.1% and is not pinned out. The Error Amplifier output is pinned out for external loop compensation and as a means for directly driving the PWM Comparator. The output was designed with a limited sink current capability of 270 mA, allowing it to be easily overridden with a pull--up resistor. This is desirable in applications that require secondary side voltage sensing, Figure 22. In this application, the Voltage Feedback Input is connected to the Regulator Output. This disables the Error Amplifier by placing its output into the sink state, allowing the optocoupler transistor to directly control the PWM Comparator. A low current 6.5 V regulated output is available for biasing the Error Amplifier and any additional control system circuitry. It is capable of up to 10 mA and has short--circuit protection. This output requires an external bypass capacitor of at least 1.0 mF for stability. Thermal Shutdown and Package Internal thermal circuitry is provided to protect the Power Switch in the event that the maximum junction temperature is exceeded. When activated, typically at 155C, the Latch is forced into a ‘reset’ state, disabling the Power Switch. The Latch is allowed to ‘set’ when the Power Switch temperature falls below 145C. This feature is provided to prevent catastrophic failures from accidental device overheating. It is not intended to be used as a substitute for proper heatsinking. The MC33363A is contained in a heatsinkable plastic dual--in--line package in which the die is mounted on a special heat tab copper alloy lead frame. This tab consists of the four center ground pins that are specifically designed to improve thermal conduction from the die to the circuit board. Figures 17 and 18 show a simple and effective method of utilizing the printed circuit board medium as a heat dissipater by soldering these pins to an adequate area of copper foil. This permits the use of standard layout and mounting practices while having the ability to halve the junction to air thermal resistance. The examples are for a symmetrical layout on a single--sided board with two ounce per square foot of copper. Figure 23 shows a practical example of a printed circuit board layout that utilizes the copper foil as a heat dissipater. Note that a jumper was added to the layout from Pins 8 to 10 in order to enhance the copper area near the device for improved thermal conductivity. The application circuit requires two ounce copper foil in order to obtain 8.0 W of continuous output power at room temperature. Overvoltage Protection An Overvoltage Protection Comparator is included to eliminate the possibility of runaway output voltage. This condition can occur if the control loop feedback signal path is broken due to an external component or connection failure. The comparator is normally used to monitor the primary side VCC voltage. When the 2.6 V threshold is exceeded, it will immediately turn off the Power Switch, and protect the load from a severe overvoltage condition. This input can also be driven from external circuitry to inhibit converter operation. Undervoltage Lockout An Undervoltage Lockout (UVLO) comparator has been incorporated to guarantee that the integrated circuit has sufficient voltage to be fully functional before the output stage is enabled. The UVLO comparator monitors the VCC voltage at Pin 3 and when it exceeds 14.5 V, the reset signal is removed from the PWM Latch allowing operation of the Power Switch. To prevent erratic switching as the threshold is crossed, 5.0 V of hysteresis is provided. http://onsemi.com 10 MC33363A F1 1.0 A D4 92 to 276 Vac Input D2 C1 47 D3 1N4006 C5 4.0 nF D1 C4 1.0 R1 13 k C3 1200 pF 3 UVLO 14.5 V/ 9.5 V 6 Osc 7 D6 R5 MUR 39 120 Startup Reg 8 11 D7 T1 MBR 1635 C2 10 R4 5.1 k 1 2 IC2 3 MOC 8103 IC3 TL431B 2 16 Driver S C9 C10 330 330 C8 330 R3 1.0 k OVP 2.6 V PWM Latch R7 2.2 k 1.0 W D5 MUR 1100E 1 Mirror C6 47 pF R6 180 k 1.0 W Q L1 5.0 H 5.05 V/3.0 A DC Output + R8 220 R9 2.80 k C7 100 nF R PWM ILimit 4 Thermal 9 270 A 2.6 V EA R2 2.7 k 10 IC1 MC33363A 4, 5, 12, 13 Figure 22. 15 W Off--Line Converter Table 1. CONVERTER TEST DATA Test Conditions Results Line Regulation Vin = 92 Vac to 276 Vac, IO 3.0 A Δ = 1.0 mV Load Regulation Vin = 115 Vac, IO = 0.75 A to 3.0 A Δ = 5.0 mV Vin = 230 Vac, IO = 0.75 A to 3.0 A Δ = 5.0 mV Vin = 115 Vac, IO = 3.0 A Triangular = 2.0 mVpp, Spike = 32 mVpp Vin = 230 Vac, IO = 3.0 A Triangular = 2.0 mVpp, Spike = 34 mVpp Vin = 115 Vac, IO = 3.0 A 76.8%* Vin = 230 Vac, IO = 3.0 A 76.8% Output Ripple Efficiency This data was taken with the components listed below mounted on the printed circuit board shown in Figure 23. *With MBR2535CTL, 78.8% efficiency. PCB layout modification is required to use this rectifier. For high efficiency and small circuit board size, the Sanyo Os--Con capacitors are recommended for C8, C9, C10 and C11. C8, C9, C10 = Sanyo Os--Con #6SA330M, 330 mF 6.3 V. C11 = Sanyo Os--Con #10SA220M, 220 mF 10 V. L1 = Coilcraft S5088--A, 5.0 mH, 0.11 Ω. T1 = Coilcraft U6875--A Primary: 77 turns of # 28 AWG, Pin 1 = start, Pin 8 = finish. Two layers 0.002 Mylar tape. Secondary: 5 turns of # 22 AWG, 2 strands bifiliar wound, Pin 5 = start, Pin 4 = finish. Two layers 0.002 Mylar tape. Auxiliary: 13 turns of # 28 AWG wound in center of bobbin, Pin 2 = start, Pin 7 = finish. Two layers 0.002 Mylar tape. Gap: 0.011 total for a primary inductance (LP) of 620 mH. Core and Bobbin: Coilcraft PT1950, E187, 3F3 material. http://onsemi.com 11 220 C12 1.0 R10 2.74 k 5 LEB 1 C11 -- MC33363A Caution! High Voltages DC Output C4 R3 R3 R2 R9 J1 R1 D1 IC3 IC2 D2 R10 C3 C7 C12 C11 IC1 F1 AC Line Input R8 R4 C2 L1 R5 D6 C10 D3 D4 D5 C9 R7 T1 C1 R6 D7 C5 C8 C6 1 (Top View) 2.75” 2.25” MC33363A (Bottom View) Figure 23. Printed Circuit Board and Component Layout (Circuit of Figure 22) http://onsemi.com 12 MC33363A PACKAGE DIMENSIONS SO--16W DW SUFFIX CASE 751N--01 ISSUE O --A-T 16 9 --B-1 0.010 (0.25) P M B NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: MILLIMETER. 3. DIMENSIONS A AND B DO NOT INCLUDE MOLD PROTRUSION. 4. MAXIMUM MOLD PROTRUSION 0.15 (0.006) PER SIDE. 5. DIMENSION D DOES NOT INCLUDE DAMBAR PROTRUSION. ALLOWABLE DAMBAR PROTRUSION SHALL BE 0.13 (0.005) TOTAL IN EXCESS OF D DIMENSION AT MAXIMUM MATERIAL CONDITION. M 8 13X J D 0.010 (0.25) M T A S B S F R X 45 _ C --T-- S K 9X SEATING PLANE M G DIM A B C D F G J K M P R S T MILLIMETERS MIN MAX 10.15 10.45 7.40 7.60 2.35 2.65 0.35 0.49 0.50 0.90 1.27 BSC 0.25 0.32 0.10 0.25 0_ 7_ 10.05 10.55 0.25 0.75 2.54 BSC 3.81 BSC INCHES MIN MAX 0.400 0.411 0.292 0.299 0.093 0.104 0.014 0.019 0.020 0.035 0.050 BSC 0.010 0.012 0.004 0.009 0_ 7_ 0.395 0.415 0.010 0.029 0.100 BSC 0.150 BSC SENSEFET is a trademark of Semiconductor Components Industries, LLC (SCILLC) ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. 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