AZ3843 Datasheet | Advanced Analog Technology

Features - Robust VREF Line/Load Regulation Low Line Regulation : 4m V Low Load Regulation : 4m V High Stability of Reference Voltage over a Full Temperature Range: 0.2m V/ o C Operating Frequency up to 500KHz High PWM Frequency Stability over a Full Temperature Range: 2.5% High PWM Frequency Stability under a Full Supply Voltage Range: 0.2% Accurate Over-temperature Protection with Hysteresis UVLO with Hysteresis CURRENT MODE PWM CONTROLLER General Description The AZ3842/3/4/5 are high performance fixed frequency current-mode PWM controller series. These integrated circuits are optimized for off-line and DC-DC converter applications with minimum external ponents. They feature under-voltage lockout (UVLO) circuit for low start-up current, trimmed oscillator for precise duty cycle control, current sense parator providing maximum current limiting and a totem pole output stage for increasing output current. In addition, these ICs also feature accurate protection against over-temperature, over-current and maximal output power. The AZ3842 and AZ3844 have UVLO thresholds of 15.5V(on) and 10V(off); The corresponding thresholds for AZ3843 and AZ3845 are 8.4 V(on) and 7.8V(off). The AZ3842 and AZ3843 can operate approaching 100% duty cycle; AZ3844 and AZ3845 can operate from zero to 50% duty cycle. These ICs are available in 3 packages: SOIC-8, DIP-8 and SOIC-14. - - - - - - Applications - - - - - - Off-line Converter DC-DC Converter Voltage Adapter CRT Monitor Power Supply Desktop Power Supply DVD/STB Power Supply SOIC-8 DIP-8 SOIC-14 Figure 1. Package Types of AZ3842/3/4/5 March 2003 Rev: 1.0 Data Sheet 4 U . .. Advanced Analog Circuits Data Sheet AZ3842/3/4/5 M Package (SOIC-14) P 1 2 3 4 5 6 7 14 13 12 11 10 9 8 VREF N/C VCC PWR VC OUTPUT GND PWR GND CURRENT MODE PWM CONTROLLER Pin Configuration P/M Package (DIP-8/SOIC-8) P VFB ISENSE RT/CT 1 2 3 4 8 7 6 5 VREF VCC OUTPUT GND N/C VFB N/C ISENSE N/C RT/CT Figure 2. Pin Configuration of AZ3842/3/4/5 (Top...