UC3843M/TR

UC2842/44/45 UC3842/43/45 CURRENT MODE PWM CONTROLLER DESCRIPTION The UC284x and UC384x are fixed frequency current mode PWM controller. They are specially designed for OFF Line and DC to DC converter applications with a minimal external components. Internally implemented circuits include a trimmed oscillator for precise duty cycle control, a temperature compensated reference, high gain error amplifier, current sensing comparator, and a high current totem pole output ideally suited for driving a power MOSFET. Protection circuitry includes built under voltage lockout and current limiting. The UC2842/44, UC3842/44 have UVLO thresholds of 16 V (on) and 10 V (off). The corresponding thresholds for the UC2843/45, UC3843/45 are 8.4V (on) and 7.6V (off). The UC2842/43, UC3842/43 can operate within 100% duty cycle. The UC2844/45, UC3844/45 can operate within 50% duty cycle. The UC2842/44/44/45 is characterized for operation from TA = -40℃ to 85℃. The UC3842/43/44/45 is characterized for operation from TA = 0℃ to 70℃. DIP8 SOP8 FEATURES  Low Start-Up and Operating Current  Under voltage Lockout With Hysteresis  High Current Totem Pole Output  Operating Frequency Up To 500KHz ORDERING INFORMATION DEVICE Package Type MARKING Packing Packing Qty UC2842N DIP8 UC2842 TUBE 2000/box UC2843N DIP8 UC2843 TUBE 2000/box UC2844N DIP8 UC2844 TUBE 2000/box UC2845N DIP8 UC2845 TUBE 2000/box UC2842M/TR SOP8 UC2842 REEL 2500/reel UC2843M/TR SOP8 UC2843 REEL 2500/reel UC2844M/TR SOP8 UC2844 REEL 2500/reel UC2845M/TR SOP8 UC2845 REEL 2500/reel UC3842N DIP8 UC3842 TUBE 2000/box UC3843N DIP8 UC3843 TUBE 2000/box UC3844N DIP8 UC3844 TUBE 2000/box UC3845N DIP8 UC3845 TUBE 2000/box UC3842M/TR SOP8 UC3842 REEL 2500/reel UC3843M/TR SOP8 UC3843 REEL 2500/reel UC3844M/TR SOP8 UC3844 REEL 2500/reel UC3845M/TR SOP8 UC3845 REEL 2500/reel http://www.hgsemi.com.cn 1 / 11 2020 SEP UC2842/44/45 UC3842/43/45 Pin CONNECTION DIP8/SOP8 PIN FUNCTION N FUNCTION 1 COMP 2 VFB 3 ISENSE A voltage proportional to inductor current is connected to this input. The PWM uses this information to terminate the output switch conduction. 4 RT/CT The oscillator frequency and maximum Output duty cycle are programmed by connecting resistor RT to Vref and capacitor CT to ground. 5 GROUND 6 OUTPUT 7 8 VCC Vref DESCRIPTION This pin is the Error Amplifier output and is made for loop compensation. This is the inverting input of the Error Amplifier. It is normally connected to the switching power supply output through a resistor divider. This pin is the combined control circuitry and power ground. This output directly drives the gate of a power MOSFET. Peak currents up to 1A are sourced and sink by this pin. This pin is the positive supply of the integrated circuit. This is the reference output. It provides charging current for capacitor CT through resistor RT . BLOCK DIAGRAM (toggle flip flop used only in UC2844/45, UC3844/45) Absolute Maximum Ratings Characteristic Symbol VCC Supply Voltage (low impedance source) Output Current Input Voltage (Analog Inputs pins 2,3) Error Amp Output Sink Current Power Dissipation (TA=250C) Storage Temperature Range Lead Temperature (soldering 5 sec.) http://www.hgsemi.com.cn IO VI ISINK (E.A) PO Tstg TL 2 / 11 Value 30 1 0.3 to 5.5 10 1 -65 to150 260 Unit V A V mA W ℃ ℃ 2020 SEP UC2842/44/45 UC3842/43/45 Electrical characteristics (*VCC=15V, RT=10k , CT=3.3nF, TA=00C to +700C, unless otherwise specified) Characteristics Reference Section Reference Output Voltage Line Regulation Load Regulation Short Circuit Output Current Oscillator Section Oscillation Frequency Symbol VREF VREF VREF Test Condition TJ = 25°C, IREF = 1 mA 12V  VCC  25 V ISC 1 mA  IREF  20mA TA = 25°C f TJ = 25°C Min Typ Max Unit 4.9 5.0 6.0 5.1 20 V 6.0 -100 25 -180 mA 52 57 KHz Frequency Change with Voltage f/VCC V(OSC) Oscillator Amplitude 12V  VCC  25 V (peak to peak) 0.05 1.6 1.0 % V Error Amplifier Section Input Bias Current VFB=3V -0.1 -2 µA 2.58 V dB Input Voltage Open Loop Voltage Gain Unity Gain Bandwidth Power Supply Rejection Ratio Output Sink Current Output Source Current High Output Voltage Low Output Voltage Current Sense Section Gain Maximum Input Signal Supply Voltage Rejection Input Bias Current Output Section IBIAS VI(E.A) AVOL UGBW PSRR ISINK ISOURCE VOH VOL GV VI(MAX) SVR IBIAS 47 mV Vpin1 = 2.5V 2V  V0  4V 2.42 65 2.5 90 Tj=250C, Note 3 12V  VCC  25 V 0.5 60 0.6 70 MHz dB Vpin2 = 2.7V, Vpin1 = 1.1V Vpin2 = 2.3V, Vpin1 = 5V 2 -0.5 7 -1.0 mA mA Vpin2 = 2.3V, RL = 15K to GND Vpin2 = 2.7V, RL = 15K to PIN 8 5.0 6.0 0.8 1.1 (Note 1 & 2) 2.85 3.0 3.15 V/V V pin1 = 5V (Note1) 12V  VCC  25 V (Note 1) 0.9 1.0 70 1.1 V dB Vpin3 = 3V -3.0 -10 µA 0.08 1.4 0.4 2.2 Low Output Voltage VOL ISINK = 20 mA ISINK = 200 mA High Output Voltage VOH ISINK = 20 mA ISINK = 200 mA Rise Time Fall Time tR tF TJ = 25℃, CL = 1nF (Note 3) TJ = 25℃, CL = 1nF (Note 3) 13 12 13.5 13.0 45 35 150 150 V V nS Undervoltage Lockout Section Start Theshold VTH(ST) Min. Operating Voltage (After Turn On) VOPR(min) UC2842/44,UC3842/44 14.5 16.0 17.5 UC2843/45,UC3843/45 UC2842/44,UC3842/44 7.8 8.5 8.4 10 9.0 11.5 UC2843/45,UC3843/45 7.0 7.6 8.2 UC2842/43,UC3842/43 UC2844/45,UC3844/45 95 47 97 48 100 50 V V PWM Section Max. Duty Cycle D(MAX) Min. Duty Cycle Total Standby Current D(MAX) Start Up Current Operating Supply Current IST ICC (OPR) UC3842/43/44/45 Vpin3 = Vpin2 = 0V Zener Voltage VZ ICC=25 mA % 0 0.17 13 30 38 0.3 17 mA V * Adjust VCC above the start threshold before setting it to 15V. Note 1: Parameter measured at trip point of latch with Vpin2=0. Note 2: Gain defined as A=∆Vpin1/∆Vpin3 ; 0 ≤ Vpin3 ≤ 0.8V. Note 3: These parameters, although guaranteed, are not 100% tested in production. http://www.hgsemi.com.cn 3 / 11 2020 SEP UC2842/44/45 UC3842/43/45 APPLICATION INFORMATION Figure 1. Error Amp Configuration Figure 2. Under voltage Lockout http://www.hgsemi.com.cn 4 / 11 2020 SEP UC2842/44/45 UC3842/43/45 Figure 3. Current Sense Circuit Figure 4. Slope Compensation Techniques http://www.hgsemi.com.cn 5 / 11 2020 SEP UC2842/44/45 UC3842/43/45 Figure 5. Latched Shutdown Figure 6. Error Amplifier Compensation http://www.hgsemi.com.cn 6 / 11 2020 SEP UC2842/44/45 UC3842/43/45 Figure 7. External Clock Synchronization Figure 8. Soft-Start Circuit http://www.hgsemi.com.cn 7 / 11 2020 SEP UC2842/44/45 UC3842/43/45 TYPICAL PERFORMANCE CHARACTERISTICS Figure 1. Timing Resistor vs. Oscillator Frequency Figure 2. Output Dead-Time vs. Oscillator Frequency Figure 3. Maximum Output Duty Cycle vs.Timing Figure 4. Error Amp Open-Loop Gain vs. Frequency Resistor (UC3842/43) Figure 5. Current Sense Input Threshold vs. Error Figure 6. Reference Short Circuit Current vs. Amp Output Voltage Temperature http://www.hgsemi.com.cn 8 / 11 2020 SEP UC2842/44/45 UC3842/43/45 Figure 7. Output Saturation Voltage vs. Load Current Figure 8. Supply Current vs. Supply Voltage TA = 25°C Figure 9. Oscillator and Output Waveforms http://www.hgsemi.com.cn 9 / 11 2020 SEP UC2842/44/45 UC3842/43/45 Physical Dimensions SOP8 Q A C C1 B D A1 a 0.25 b Dimensions In Millimeters(SOP8) A A1 B C C1 D Min： 1.35 0.05 4.90 5.80 3.80 0.40 0° 0.35 Max： 1.55 0.20 5.10 6.20 4.00 0.80 8° 0.45 Symbol： Q a b 1.27 BSC DIP8 D1 L1 L E B d D A c a b Dimensions In Millimeters(DIP8) A B D D1 E L L1 a b c Min： 6.10 9.00 8.40 7.42 3.10 0.50 3.00 1.50 0.85 0.40 Max： 6.68 9.50 9.00 7.82 3.55 0.70 3.60 1.55 0.90 0.50 Symbol： http://www.hgsemi.com.cn 10 / 11 d 2.54 BSC 2020 SEP UC2842/44/45 UC3842/43/45 IMPORTANT STATEMENT: Huaguan Semiconductor reserves the right to change its products and services without notice. Before ordering, the customer shall obtain the latest relevant information and verify whether the information is up to date and complete. Huaguan Semiconductor does not assume any responsibility or obligation for the altered documents. 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You should fully compensate Huaguan Semiconductor and its agents for any claims, damages, costs, losses and debts caused by the use of these resources. Huaguan Semiconductor is not responsible for this. http://www.hgsemi.com.cn 11 / 11 2020 SEP