KA3842AC/KA3842AE SMPS Controller Features Description Low start current 0.2mA (Typ.) The KA3842AC/KA3842AE are fixed PWM controllers for Off Line and DC to DC converter applications. The internal circuits include UVLO, low start up current, temperature compensated reference, high gain error amplifier, current sensing comparator, and high current totem pole output for driving a POWER MOSFET. Also KA3842AC/KA3842AE provides low start up current below 0.3mA and short shutdown delay time, typically 100ns. The KA3842AC/KA3842AE has a UVLO threshold of 16V(on) and 10V(off). The KA3842AC/KA3842AE can operate within a 100% duty cycle. Operating range up to 500kHz Cycle by cycle current limiting Under Voltage Lock Out (UVLO) with hysteresis Short shutdown delay time: Typ.100ns High current totem-pole output Output swing limiting: 22V 1 8-DIP Ordering Information Part Number Operating Temp. Range Pb-Free Package Packing Method KA3842AC -0 to +70°C Yes 8-DIP Tube KA3842AE ©2006 Fairchild Semiconductor Corporation KA3842AC/KA3842AE Rev. 1.0.1 1 www.fairchildsemi.com KA3842AC/KA3842AE SMPS Controller March 2006 7 VCC 29V SET/ RESET 5V VREF VREF 8 5 GND UVLO Internal Bias Good LOGIC 7 PWR VC 1/2 VREF VFB 2 Error Amp + - C.S PWM Comp. LATCH 1/3 R 22V 1V 6 OUTPUT S COMP 1 T C.S 3 RT/CT 4 KA3842AC/KA3842AE Rev. 1.0.1 5 PWR GND OSCILLATOR 2 www.fairchildsemi.com KA3842AC/KA3842AE SMPS Controller Internal Block Diagram The “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. The device should not be operated at these limits. The parametric values defined in the Electrical Characteristics tables are not guaranteed at the absolute maximum ratings. The “Recommended Operating Conditions” table will define the conditions for actual device operation. Symbol Parameter Value Unit VCC Supply Voltage 30 V IO Output Current ±1 A -0.3 to 6.3 V Error Amp. Output Sink Current 10 mA Power Dissipation 1 W 95 °C/W VI(ANA) ISINK(EA) PD Rθja Analog Inputs (Pins 2, 3) Thermal Resistance, Junction-to-Air (4) Electrical Characteristics (VCC = 15V, RT = 10k¾, CT = 3.3nF, TA = 0°C to +70°C, unless otherwise specified) Symbol Parameter Conditions Min. Typ. Max. Unit REFERENCE SECTION VREF Output Voltage TJ = 25°C, IO = 1mA 4.9 5.0 5.1 V ΔVREF Line Regulation VCC = 12V to 25V – 6 20 mV Load Regulation IO = 1mA to 20mA – 6 25 mV Output Short Circuit TA = 25°C – -100 -180 mA ISC OSILLATOR SECTION FOSC Initial Accuracy TJ = 25°C 47 52 57 kHz STV Voltage Stability VCC = 12V to 25V – 0.2 1 % VOSC Amplitude VPIN4, Peak to Peak – 1.7 – V IDISCHG Discharge Current TJ = 25°C, Pin 4 = 2V 7.8 8.3 8.8 mA 2.85 3 3.15 V/V 0.9 1.0 1.1 V – 70 – dB CURRENT SENSE SECTION GV Gain(2)(3) Signal(2) VI(MAX) Maximum Input PSRR PSRR(1)(2) IBIAS Input Bias Current TD Delay to Output(1) VPIN1 = 5V VCC = 12V to 25V VPIN3 = 0 V to 2V – -2 -10 µA – 100 200 ns 2.42 2.50 2.58 V ERROR AMPLIFIER SECTION VI Input Voltage IBIAS Input Bias Current GVO Open Loop Gain(1) TPIN1 = 2.5V (1) – -0.3 -2 µA VO = 2V to 4V 65 90 – dB – MHz GBW Unity Gain Bandwidth TJ = 25°C 0.7 1 PSRR PSRR(1) VCC = 12V to 25V 60 70 – dB ISINK Output Sink Current VPIN2 = 2.7V VPIN1 = 1.1V 2 6 – mA ISOURCE Output Source Current VPIN2 = 2.3V VPIN1 = 5.0V -0.5 -0.8 – mA VOH Output High Voltage VPIN2 = 2.3V, R1 = 15k¾ to GND 5 6 – V VOL Output Low Voltage VPIN2 = 2.7V R1 = 15k¾ to Pin 8 – 0.8 1.1 V KA3842AC/KA3842AE Rev. 1.0.1 3 www.fairchildsemi.com KA3842AC/KA3842AE SMPS Controller Absolute Maximum Ratings (VCC = 15V, RT = 10k¾, CT = 3.3nF, TA = 0°C to +70°C, unless otherwise specified) Symbol Parameter Conditions Min. Typ. Max. Unit – 0.1 0.4 V OUTPUT SECTION VOL Output Low Level VOH Output High Level tR Rise Time(1) tF VOLIM ISINK = 20mA ISINK = 200mA – 1.5 2.2 V ISOURCE = 20mA 13 13.5 – V ISOURCE = 200mA 12 13.5 – V TJ = 25°C, C1 = 1nF – 40 100 ns Fall Time(1) TJ = 25°C, C1 = 1nF – 40 100 ns Output Voltage Swing Limit VCC = 27V, C1 = 1nF – 22 – V UNDER VOLTAGE LOCKOUT SECTION VTH Start Threshold 15 16 17 V VTL Min. Operating Voltage (After turn on) 9 10 11 V PWM SECTION DMAX Maximum Duty Cycle 94 96 100 % DMIN Minimum Duty Cycle – – 0 % – 0.2 0.4 mA TOTAL STANDBY CURRENT IST Start-Up Current ICC Operating Supply Current VPIN2 = VPIN3 = 0V – 11 17 mA VZ VCC Zener Voltage ICC = 25mA – 29 – V * Adjust VCC above the start threshold before setting at 15V Notes: 1. 2. 3. 4. These parameters, although guaranteed, are not 100% tested in production. Parameter measured at trip point of latch with V2 = 0V. Gain defined as: GV = ΔVPIN1ΔVPIN3(VPIN3 = 0 to 0.8V) Junction-to-air thermal resistance test environments PCB information: Board thickness; 1.6mm, Board dimension: 76.2 X 114.3mm2, Ref.: EIA/JSED51-3 and EIA/JSED51-7 Board structure; Using the single layer PCB. KA3842AC/KA3842AE Rev. 1.0.1 4 www.fairchildsemi.com KA3842AC/KA3842AE SMPS Controller Electrical Characteristics (Continued) 8-Pin DIP Dimensions in millimeters KA3842AC/KA3842AE Rev. 1.0.1 5 www.fairchildsemi.com KA3842AC/KA3842AE SMPS Controller Package Dimensions The following are registered and unregistered trademarks Fairchild Semiconductor owns or is authorized to use and is not intended to be an exhaustive list of all such trademarks. ACEx™ FAST® ActiveArray™ FASTr™ Bottomless™ FPS™ Build it Now™ FRFET™ CoolFET™ GlobalOptoisolator™ CROSSVOLT™ GTO™ DOME™ HiSeC™ EcoSPARK™ I2C™ E2CMOS™ i-Lo™ EnSigna™ ImpliedDisconnect™ FACT™ IntelliMAX™ FACT Quiet Series™ Across the board. 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PRODUCT STATUS DEFINITIONS Definition of Terms Datasheet Identification Product Status Definition Advance Information Formative or In Design This datasheet contains the design specifications for product development. Specifications may change in any manner without notice. Preliminary First Production This datasheet contains preliminary data, and supplementary data will be published at a later date. Fairchild Semiconductor reserves the right to make changes at any time without notice in order to improve design. No Identification Needed Full Production This datasheet contains final specifications. Fairchild Semiconductor reserves the right to make changes at any time without notice in order to improve design. Obsolete Not In Production This datasheet contains specifications on a product that has been discontinued by Fairchild semiconductor. The datasheet is printed for reference information only. Rev. I18 KA3842AC/KA3842AE Rev. 1.0.1 6 www.fairchildsemi.com KA3842AC/KA3842AE SMPS Controller TRADEMARKS