UC3842 Fairchild Semiconductor, UC3842 Datasheet
UC3842
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UC3842 Summary of contents
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... Power MOSFET. The UC3842 and UC3844 have UVLO thresholds of 16V (on) and 10V (off). The UC3843 and UC3845 are 8.5V(on) and 7.9V (off). The UC3842 and UC3843 can operate within 100% duty cycle. The UC3844 and UC3845 can operate with 50% duty cycle. ...
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... UC3842/UC3843/UC3844/UC3845 Absolute Maximum Ratings Parameter Supply Voltage Output Current Analog Inputs (Pin 2.3) Error Amp Output Sink Current Power Dissipation (8DIP) A Power Dissipation (8SOP) A Power Dissipation (14SOP) A Storage Temperature Range Lead Temperature (Soldering, 10sec) Note: 1. Board Thickness 1.6mm, Board Dimension 76.2mm 114.3mm, (Reference EIA / JSED51-3, 51-7) 2 ...
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... I(MAX) pin1 PSRR 12V V 25V (Note 1, BIAS I = 20mA V SINK 200mA SINK I = 20mA SOURCE 200mA SOURCE 1nF (Note 1nF (Note UC3842/UC3844 TH(ST) UC3843/UC3845 UC3842/UC3844 OPR(MIN) UC3843/UC3844 UC3842/UC3843/UC3844/UC3845 Min. Typ. Max. 4.90 5.00 5. -100 -180 0. 1 -0.1 -2 2.42 2.50 2. -0.6 -1 GND Pin ...
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... The transistor and 5k potentiometer are used to sample the oscillator waveform and apply an adjustable ramp to pin 3. 4 (Continued +70 C, unless otherwise specified) A Symbol Conditions D UC3842/UC3843 (Max) D UC3844/UC3845 (Max (MIN =ON CC(OPR) pin3 pin2 25mA Z CC UC3842 Figure 1. Open Loop Test Circuit Min. Typ. Max. Unit 95 97 100 % 0. ...
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... During Under-Voltage Lock-Out, the output driver is biased to a high impedance state. Pin 6 should be shunted to ground with a bleeder resistor to prevent activating the power switch with output leakage current. Peak current ( determined by the formula: S 1.0V I MAX = ----------- - small RC filter may be required to suppress switch transients. UC3842/44 UC3843/45 Figure 2. Under Voltage Lockout Figure 3. Error Amp Configuration Figure 4. Current Sense Circuit UC3842/UC3843/UC3844/UC3845 5 ...
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... UC3842/UC3843/UC3844/UC3845 Figure 5. Oscillator Waveforms and Maximum Duty Cycle Oscillator timing capacitor charged discharge time, the internal clock signal blanks the output to the low state. Selection of R oscillator frequency and maximum duty cycle. Charge and discharge times are determined by the formulas 0.55 R ...
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... Shutdown of the UC3842 can be accomplished by two methods; either raise pin 3 above 1V or pull pin 1 below a voltage two diode drops above ground. Either method causes the output of the PWM comparator to be high (refer to block diagram). The PWM latch is reset dominant so that the output will remain low until the next clock cycle after the shutdown condition at pins 1 and/ removed ...
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... UC3842/UC3843/UC3844/UC3845 Mechanical Dimensions Package 6.40 0.20 0.252 0.008 # 7.62 0.300 8 8-DIP 5.08 MAX 0.200 3.40 0.33 0.20 0.013 0.134 0.008 3.30 0.30 0.130 0.012 MIN ...
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... Mechanical Dimensions Package #1 #4 6.00 0.236 3.95 0.156 5.72 0.225 0.50 0.20 0.020 0.008 (Continued) 8-SOP 1.55 0.20 0.061 0.008 #8 #5 0.30 1.80 MAX 0.012 0.071 0.20 0.008 UC3842/UC3843/UC3844/UC3845 0.1~0.25 MIN 0.004~0.001 9 ...
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... UC3842/UC3843/UC3844/UC3845 Mechanical Dimensions Package #1 #7 6.00 0.236 3.95 0.156 5.72 0.225 0.60 0.20 0.024 0.008 10 (Continued) 14-SOP 1.55 0.10 0.061 0.004 #14 #8 0.30 1.80 MAX 0.071 0.012 0.20 0.008 0.05 MIN 0.002 ...
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... Ordering Information Product Number UC3842N UC3843N UC3844N UC3845N UC3842D1 UC3843D1 UC3844D1 UC3845D1 UC3842D UC3843D UC3844D UC3845D Package Operating Temperature 8-DIP 8-SOP 14-SOP UC3842/UC3843/UC3844/UC3845 11 ...
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... UC3842/UC3843/UC3844/UC3845 DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. ...