FAIRCHILD UC3525A SMPS Controller handbook
Contents
1. RL 210MQ 60 80 dB Common Mode Rejection Ratio CMRR 1 5 to 5 2V 60 90 dB Power Supply Rejection Ratio PSRR Vcc 8 to 3 5V 50 60 dB PWM COMPARATOR SECTION Minimum Duty Cycle D MIN 0 Yo Duty Cycle 45 49 Yo Input Threshold Voltage Note 2 VTH1 Zero Duty Cycle 0 7 09 V Input Threshold Voltage Note 2 VTH2 Max Duty Cycle 3 2 3 6 V SOFT START SECTION Soft Start Current ISOFT VSD OV VSS OV 25 51 80 Start Low Level Voltage VSL VSD 25V 0 3 0 7 V Shutdown Threshold Voltage VTH SD 0 6 0 8 1 V Shutdown Input Current IN SD VSD 2 5 0 3 1 mA OUTPUT SECTION Low Output Voltage VOLI ISINK 20 0 1 0 4 V Low Output Voltage Il VOL Il ISINK 100mA 0 05 2 V High Output Voltage VCH I ISOURCE 20mA 18 19 V High Output Voltage Il VCH II ISOURCE 100mA 17 18 V Under Voltage Lockout VUV V8 and V9 High 6 7 8 V Collector Leakage Current ILKG 35V 80 200 uA Rise Time Note 1 tr CL 1uF Ty 25 C 80 600 ns Fall Time Note 1 1uF Ty 25 C 70 300 ns STANDBY CURRENT Supply Current lec VCC 35V 12 20 mA Notes 1 These parameters although guaranteed over the recommended operating conditions are not 100 tested in production 2 Tested at fosc 40 KHz RT 8 6K CT 0 01uF R 00 UC3525A Test Circuit SHUTDOWN UC3525A Mechan2. specified Parameter Symbol Conditions Min Unit REFERENCE SECTION Reference Output Voltage VREF TJ 25 C 5 0 5 1 5 2 V Line Regulation AVREF 8 to 35V 9 20 mV Load Regulation AVREF IREF 0 to 20mA 20 50 mV Short Circuit Output Current ISC VREF 0 Ty 25 C 80 100 mA Total Output Variation Note 1 AVREF Line Load and Temperature 4 95 5 25 V Temperature Stability Note 1 STT 20 50 mV Long Term Stability Note 1 ST TJ 125 1 KHRs 20 50 mV OSCILLATOR SECTION Initial Accuracy Note 1 2 ACCUR Ty 25 C 3 Frequency Change With Voltage Af AVCC Vcc 8 to 35V Note 1 2 t0 8 Maximum Frequency f MAX RT 2KQ CT 470pF 400 430 KHz Minimum Frequency f MIN RT 200KQ CT 0 1uF 60 120 Hz Clock Amplitude Note 1 2 V CLK 3 4 V Clock Width Note 1 2 tW CLK 25 C 0 3 0 6 1 us Sync Threshold VTH SYNC 12 2 28 V Sync Input Current SYNC Sync 3 5V 1 3 2 5 mA UC3525A Electrical Characteristics 20 TA 0 to 85 C unless otherwise specified Parameter Symbol Conditions Min Typ Max Unit ERROR AMPLIFIER SECTION 5 1V Input Offset Voltage s 1 5 10 mV Input Bias Current IBIAS 1 10 uA Input Offset Current 0 1 1 Open Loop Voltage Gain
3. Q0UC32 00 A FAIRCHILD I SEMICONDUCTOR UC3525A SMPS Controller www fairchildsemi com Features Description e SV 1 Reference UC3525A is monolithic integrated circuit that Included Oscillator Sync terminal all of the control circuit necessary for a pulse width modulat e Internal Soft Start ing regulator There are a voltage reference an error ampli Deadtime Control fier a pulse width modulator an oscillator under voltage e Under Voltage Lockout lockout soft start circuit and output drivers in the chip 16 DIP Internal Block Diagram mC 12 o De EA 2 OUTPUT A EA OUT gt LATCH 8 LA in TT Hl gt sy Q SHUT DOWN 10 vV DISCHARGE QOQ SYNC OSC OUTPUT Rev 5 0 2000 Fairchild Semiconductor International UC3525A Absolute Maximum Ratings Parameter Symbol Value Unit Supply Voltage 40 V Collector Supply Voltage VC 40 V Output Current Sink or Source lo 500 mA Reference Output Current IREF 50 mA Oscillator Charging Current ICHG OSC 5 mA Power Dissipation TA 25 C PD 1000 m W Operating Temperature TOPR 0 70 C Storage Temperature TSTG 65 150 Lead Temperature Soldering 10 sec TLEAD 300 C Electrical Characteristics 20V 30 to 85 C unless otherwise
4. ical Dimensions Package 16 DIP 6 40 0 20 0 252 0 008 19 80 MAX 19 40 0 20 0 764 0 008 0 780 3 25 0 20 0 128 0 008 _ 0 46 0 10 0 018 0 004 1 50 0 10 0 059 0 004 la 0 38 0 014 MIN 5 08 0 200 3 30 0 30 E 0 130 0 012 0 10 0 25 1005 A an a 0 004 0 19 0 010 9002 UC3525A Ordering Information Product Number Package Operating Temperature UC3525AN 16 DIP 30 85 C UC3525A UC3525A LIFE SUPPORT POLICY FAIRCHILD S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EKPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR INTERNATIONAL As used herein 1 Life support devices or systems are devices or systems 2 critical component in any component of a life support which a are intended for surgical implant into the body device or system whose failure to perform can be or b support or sustain life and c whose failure to reasonably expected to cause the failure of the life support perform when properly used in accordance with device or system or to affect its safety or effectiveness instructions for use provided in the labeling can be reasonably expected to result in a significant injury of the user www fairchildsemi com 7 12 00 0 0m 001 Stock DSxxxxxxxx 2000 Fairchi
5. ld Semiconductor International
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FAIRCHILD UC3525A SMPS Controller handbook